Create a Message

client.Beta.Messages.New(ctx, params) (*BetaMessage, error)

POST/v1/messages

Send a structured list of input messages with text and/or image content, and the model will generate the next message in the conversation.

The Messages API can be used for either single queries or stateless multi-turn conversations.

Learn more about the Messages API in our user guide

ParametersExpand Collapse

params BetaMessageNewParams

MaxTokens param.Field[int64]

Body param: The maximum number of tokens to generate before stopping.

Note that our models may stop before reaching this maximum. This parameter only specifies the absolute maximum number of tokens to generate.

Different models have different maximum values for this parameter. See models for details.

minimum1

Messages param.Field[[]BetaMessageParamResp]

Body param: Input messages.

Our models are trained to operate on alternating user and assistant conversational turns. When creating a new Message, you specify the prior conversational turns with the messages parameter, and the model then generates the next Message in the conversation. Consecutive user or assistant turns in your request will be combined into a single turn.

Each input message must be an object with a role and content. You can specify a single user-role message, or you can include multiple user and assistant messages.

If the final message uses the assistant role, the response content will continue immediately from the content in that message. This can be used to constrain part of the model's response.

Example with a single user message:

[{"role": "user", "content": "Hello, Claude"}]

Example with multiple conversational turns:

[
  {"role": "user", "content": "Hello there."},
  {"role": "assistant", "content": "Hi, I'm Claude. How can I help you?"},
  {"role": "user", "content": "Can you explain LLMs in plain English?"},
]

Example with a partially-filled response from Claude:

[
  {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
  {"role": "assistant", "content": "The best answer is ("},
]

Each input message content may be either a single string or an array of content blocks, where each block has a specific type. Using a string for content is shorthand for an array of one content block of type "text". The following input messages are equivalent:

{"role": "user", "content": "Hello, Claude"}

{"role": "user", "content": [{"type": "text", "text": "Hello, Claude"}]}

See input examples.

Note that if you want to include a system prompt, you can use the top-level system parameter — there is no "system" role for input messages in the Messages API.

There is a limit of 100,000 messages in a single request.

Content []BetaContentBlockParamUnionResp

Accepts one of the following:

[]BetaContentBlockParamUnionResp

Accepts one of the following:

type BetaTextBlockParamResp struct{…}

Text string

Type Text

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations []BetaTextCitationParamUnionRespoptional

Accepts one of the following:

type BetaCitationCharLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationWebSearchResultLocationParamResp struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocationParamResp struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

type BetaImageBlockParamResp struct{…}

Source BetaImageBlockParamSourceUnionResp

Accepts one of the following:

type BetaBase64ImageSource struct{…}

Data string

MediaType BetaBase64ImageSourceMediaType

Accepts one of the following:

const BetaBase64ImageSourceMediaTypeImageJPEG BetaBase64ImageSourceMediaType = "image/jpeg"

const BetaBase64ImageSourceMediaTypeImagePNG BetaBase64ImageSourceMediaType = "image/png"

const BetaBase64ImageSourceMediaTypeImageGIF BetaBase64ImageSourceMediaType = "image/gif"

const BetaBase64ImageSourceMediaTypeImageWebP BetaBase64ImageSourceMediaType = "image/webp"

Type Base64

type BetaURLImageSource struct{…}

Type URL

URL string

type BetaFileImageSource struct{…}

FileID string

Type File

Type Image

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

type BetaRequestDocumentBlock struct{…}

Source BetaRequestDocumentBlockSourceUnion

Accepts one of the following:

type BetaBase64PDFSource struct{…}

Data string

MediaType ApplicationPDF

Type Base64

type BetaPlainTextSource struct{…}

Data string

MediaType TextPlain

Type Text

type BetaContentBlockSource struct{…}

Content BetaContentBlockSourceContentUnion

Accepts one of the following:

string

[]BetaContentBlockSourceContentUnion

Accepts one of the following:

type BetaTextBlockParamResp struct{…}

Text string

Type Text

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations []BetaTextCitationParamUnionRespoptional

Accepts one of the following:

type BetaCitationCharLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationWebSearchResultLocationParamResp struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocationParamResp struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

type BetaImageBlockParamResp struct{…}

Source BetaImageBlockParamSourceUnionResp

Accepts one of the following:

type BetaBase64ImageSource struct{…}

Data string

MediaType BetaBase64ImageSourceMediaType

Accepts one of the following:

const BetaBase64ImageSourceMediaTypeImageJPEG BetaBase64ImageSourceMediaType = "image/jpeg"

const BetaBase64ImageSourceMediaTypeImagePNG BetaBase64ImageSourceMediaType = "image/png"

const BetaBase64ImageSourceMediaTypeImageGIF BetaBase64ImageSourceMediaType = "image/gif"

const BetaBase64ImageSourceMediaTypeImageWebP BetaBase64ImageSourceMediaType = "image/webp"

Type Base64

type BetaURLImageSource struct{…}

Type URL

URL string

type BetaFileImageSource struct{…}

FileID string

Type File

Type Image

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Type Content

type BetaURLPDFSource struct{…}

Type URL

URL string

type BetaFileDocumentSource struct{…}

FileID string

Type File

Type Document

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations BetaCitationsConfigParamRespoptional

Enabled booloptional

Context stringoptional

Title stringoptional

type BetaSearchResultBlockParamResp struct{…}

Content []BetaTextBlockParamResp

Text string

Type Text

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations []BetaTextCitationParamUnionRespoptional

Accepts one of the following:

type BetaCitationCharLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationWebSearchResultLocationParamResp struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocationParamResp struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Source string

Title string

Type SearchResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations BetaCitationsConfigParamRespoptional

Enabled booloptional

type BetaThinkingBlockParamResp struct{…}

Signature string

Thinking string

Type Thinking

type BetaRedactedThinkingBlockParamResp struct{…}

Data string

Type RedactedThinking

type BetaToolUseBlockParamResp struct{…}

ID string

Input map[string, any]

Name string

Type ToolUse

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Caller BetaToolUseBlockParamCallerUnionRespoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaToolResultBlockParamResp struct{…}

ToolUseID string

Type ToolResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Content []BetaToolResultBlockParamContentUnionRespoptional

Accepts one of the following:

[]BetaToolResultBlockParamContentUnionResp

Accepts one of the following:

type BetaTextBlockParamResp struct{…}

Text string

Type Text

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations []BetaTextCitationParamUnionRespoptional

Accepts one of the following:

type BetaCitationCharLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationWebSearchResultLocationParamResp struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocationParamResp struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

type BetaImageBlockParamResp struct{…}

Source BetaImageBlockParamSourceUnionResp

Accepts one of the following:

type BetaBase64ImageSource struct{…}

Data string

MediaType BetaBase64ImageSourceMediaType

Accepts one of the following:

const BetaBase64ImageSourceMediaTypeImageJPEG BetaBase64ImageSourceMediaType = "image/jpeg"

const BetaBase64ImageSourceMediaTypeImagePNG BetaBase64ImageSourceMediaType = "image/png"

const BetaBase64ImageSourceMediaTypeImageGIF BetaBase64ImageSourceMediaType = "image/gif"

const BetaBase64ImageSourceMediaTypeImageWebP BetaBase64ImageSourceMediaType = "image/webp"

Type Base64

type BetaURLImageSource struct{…}

Type URL

URL string

type BetaFileImageSource struct{…}

FileID string

Type File

Type Image

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

type BetaSearchResultBlockParamResp struct{…}

Content []BetaTextBlockParamResp

Text string

Type Text

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations []BetaTextCitationParamUnionRespoptional

Accepts one of the following:

type BetaCitationCharLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationWebSearchResultLocationParamResp struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocationParamResp struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Source string

Title string

Type SearchResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations BetaCitationsConfigParamRespoptional

Enabled booloptional

type BetaRequestDocumentBlock struct{…}

Source BetaRequestDocumentBlockSourceUnion

Accepts one of the following:

type BetaBase64PDFSource struct{…}

Data string

MediaType ApplicationPDF

Type Base64

type BetaPlainTextSource struct{…}

Data string

MediaType TextPlain

Type Text

type BetaContentBlockSource struct{…}

Content BetaContentBlockSourceContentUnion

Accepts one of the following:

string

[]BetaContentBlockSourceContentUnion

Accepts one of the following:

type BetaTextBlockParamResp struct{…}

Text string

Type Text

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations []BetaTextCitationParamUnionRespoptional

Accepts one of the following:

type BetaCitationCharLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationWebSearchResultLocationParamResp struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocationParamResp struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

type BetaImageBlockParamResp struct{…}

Source BetaImageBlockParamSourceUnionResp

Accepts one of the following:

type BetaBase64ImageSource struct{…}

Data string

MediaType BetaBase64ImageSourceMediaType

Accepts one of the following:

const BetaBase64ImageSourceMediaTypeImageJPEG BetaBase64ImageSourceMediaType = "image/jpeg"

const BetaBase64ImageSourceMediaTypeImagePNG BetaBase64ImageSourceMediaType = "image/png"

const BetaBase64ImageSourceMediaTypeImageGIF BetaBase64ImageSourceMediaType = "image/gif"

const BetaBase64ImageSourceMediaTypeImageWebP BetaBase64ImageSourceMediaType = "image/webp"

Type Base64

type BetaURLImageSource struct{…}

Type URL

URL string

type BetaFileImageSource struct{…}

FileID string

Type File

Type Image

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Type Content

type BetaURLPDFSource struct{…}

Type URL

URL string

type BetaFileDocumentSource struct{…}

FileID string

Type File

Type Document

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations BetaCitationsConfigParamRespoptional

Enabled booloptional

Context stringoptional

Title stringoptional

type BetaToolReferenceBlockParamResp struct{…}

Tool reference block that can be included in tool_result content.

ToolName string

Type ToolReference

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

IsError booloptional

type BetaServerToolUseBlockParamResp struct{…}

ID string

Input map[string, any]

Name BetaServerToolUseBlockParamName

Accepts one of the following:

const BetaServerToolUseBlockParamNameWebSearch BetaServerToolUseBlockParamName = "web_search"

const BetaServerToolUseBlockParamNameWebFetch BetaServerToolUseBlockParamName = "web_fetch"

const BetaServerToolUseBlockParamNameCodeExecution BetaServerToolUseBlockParamName = "code_execution"

const BetaServerToolUseBlockParamNameBashCodeExecution BetaServerToolUseBlockParamName = "bash_code_execution"

const BetaServerToolUseBlockParamNameTextEditorCodeExecution BetaServerToolUseBlockParamName = "text_editor_code_execution"

const BetaServerToolUseBlockParamNameToolSearchToolRegex BetaServerToolUseBlockParamName = "tool_search_tool_regex"

const BetaServerToolUseBlockParamNameToolSearchToolBm25 BetaServerToolUseBlockParamName = "tool_search_tool_bm25"

Type ServerToolUse

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Caller BetaServerToolUseBlockParamCallerUnionRespoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaWebSearchToolResultBlockParamResp struct{…}

Content BetaWebSearchToolResultBlockParamContentUnionResp

Accepts one of the following:

[]BetaWebSearchResultBlockParamResp

EncryptedContent string

Title string

Type WebSearchResult

URL string

PageAge stringoptional

type BetaWebSearchToolRequestError struct{…}

ErrorCode BetaWebSearchToolResultErrorCode

Accepts one of the following:

const BetaWebSearchToolResultErrorCodeInvalidToolInput BetaWebSearchToolResultErrorCode = "invalid_tool_input"

const BetaWebSearchToolResultErrorCodeUnavailable BetaWebSearchToolResultErrorCode = "unavailable"

const BetaWebSearchToolResultErrorCodeMaxUsesExceeded BetaWebSearchToolResultErrorCode = "max_uses_exceeded"

const BetaWebSearchToolResultErrorCodeTooManyRequests BetaWebSearchToolResultErrorCode = "too_many_requests"

const BetaWebSearchToolResultErrorCodeQueryTooLong BetaWebSearchToolResultErrorCode = "query_too_long"

const BetaWebSearchToolResultErrorCodeRequestTooLarge BetaWebSearchToolResultErrorCode = "request_too_large"

Type WebSearchToolResultError

ToolUseID string

Type WebSearchToolResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Caller BetaWebSearchToolResultBlockParamCallerUnionRespoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaWebFetchToolResultBlockParamResp struct{…}

Content BetaWebFetchToolResultBlockParamContentUnionResp

Accepts one of the following:

type BetaWebFetchToolResultErrorBlockParamResp struct{…}

ErrorCode BetaWebFetchToolResultErrorCode

Accepts one of the following:

const BetaWebFetchToolResultErrorCodeInvalidToolInput BetaWebFetchToolResultErrorCode = "invalid_tool_input"

const BetaWebFetchToolResultErrorCodeURLTooLong BetaWebFetchToolResultErrorCode = "url_too_long"

const BetaWebFetchToolResultErrorCodeURLNotAllowed BetaWebFetchToolResultErrorCode = "url_not_allowed"

const BetaWebFetchToolResultErrorCodeURLNotAccessible BetaWebFetchToolResultErrorCode = "url_not_accessible"

const BetaWebFetchToolResultErrorCodeUnsupportedContentType BetaWebFetchToolResultErrorCode = "unsupported_content_type"

const BetaWebFetchToolResultErrorCodeTooManyRequests BetaWebFetchToolResultErrorCode = "too_many_requests"

const BetaWebFetchToolResultErrorCodeMaxUsesExceeded BetaWebFetchToolResultErrorCode = "max_uses_exceeded"

const BetaWebFetchToolResultErrorCodeUnavailable BetaWebFetchToolResultErrorCode = "unavailable"

Type WebFetchToolResultError

type BetaWebFetchBlockParamResp struct{…}

Content BetaRequestDocumentBlock

Source BetaRequestDocumentBlockSourceUnion

Accepts one of the following:

type BetaBase64PDFSource struct{…}

Data string

MediaType ApplicationPDF

Type Base64

type BetaPlainTextSource struct{…}

Data string

MediaType TextPlain

Type Text

type BetaContentBlockSource struct{…}

Content BetaContentBlockSourceContentUnion

Accepts one of the following:

string

[]BetaContentBlockSourceContentUnion

Accepts one of the following:

type BetaTextBlockParamResp struct{…}

Text string

Type Text

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations []BetaTextCitationParamUnionRespoptional

Accepts one of the following:

type BetaCitationCharLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationWebSearchResultLocationParamResp struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocationParamResp struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

type BetaImageBlockParamResp struct{…}

Source BetaImageBlockParamSourceUnionResp

Accepts one of the following:

type BetaBase64ImageSource struct{…}

Data string

MediaType BetaBase64ImageSourceMediaType

Accepts one of the following:

const BetaBase64ImageSourceMediaTypeImageJPEG BetaBase64ImageSourceMediaType = "image/jpeg"

const BetaBase64ImageSourceMediaTypeImagePNG BetaBase64ImageSourceMediaType = "image/png"

const BetaBase64ImageSourceMediaTypeImageGIF BetaBase64ImageSourceMediaType = "image/gif"

const BetaBase64ImageSourceMediaTypeImageWebP BetaBase64ImageSourceMediaType = "image/webp"

Type Base64

type BetaURLImageSource struct{…}

Type URL

URL string

type BetaFileImageSource struct{…}

FileID string

Type File

Type Image

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Type Content

type BetaURLPDFSource struct{…}

Type URL

URL string

type BetaFileDocumentSource struct{…}

FileID string

Type File

Type Document

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations BetaCitationsConfigParamRespoptional

Enabled booloptional

Context stringoptional

Title stringoptional

Type WebFetchResult

URL string

Fetched content URL

RetrievedAt stringoptional

ISO 8601 timestamp when the content was retrieved

ToolUseID string

Type WebFetchToolResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Caller BetaWebFetchToolResultBlockParamCallerUnionRespoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaCodeExecutionToolResultBlockParamResp struct{…}

Content BetaCodeExecutionToolResultBlockParamContentUnionResp

Code execution result with encrypted stdout for PFC + web_search results.

Accepts one of the following:

type BetaCodeExecutionToolResultErrorParamResp struct{…}

ErrorCode BetaCodeExecutionToolResultErrorCode

Accepts one of the following:

const BetaCodeExecutionToolResultErrorCodeInvalidToolInput BetaCodeExecutionToolResultErrorCode = "invalid_tool_input"

const BetaCodeExecutionToolResultErrorCodeUnavailable BetaCodeExecutionToolResultErrorCode = "unavailable"

const BetaCodeExecutionToolResultErrorCodeTooManyRequests BetaCodeExecutionToolResultErrorCode = "too_many_requests"

const BetaCodeExecutionToolResultErrorCodeExecutionTimeExceeded BetaCodeExecutionToolResultErrorCode = "execution_time_exceeded"

Type CodeExecutionToolResultError

type BetaCodeExecutionResultBlockParamResp struct{…}

Content []BetaCodeExecutionOutputBlockParamResp

FileID string

Type CodeExecutionOutput

ReturnCode int64

Stderr string

Stdout string

Type CodeExecutionResult

type BetaEncryptedCodeExecutionResultBlockParamResp struct{…}

Code execution result with encrypted stdout for PFC + web_search results.

Content []BetaCodeExecutionOutputBlockParamResp

FileID string

Type CodeExecutionOutput

EncryptedStdout string

ReturnCode int64

Stderr string

Type EncryptedCodeExecutionResult

ToolUseID string

Type CodeExecutionToolResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

type BetaBashCodeExecutionToolResultBlockParamResp struct{…}

Content BetaBashCodeExecutionToolResultBlockParamContentUnionResp

Accepts one of the following:

type BetaBashCodeExecutionToolResultErrorParamResp struct{…}

ErrorCode BetaBashCodeExecutionToolResultErrorParamErrorCode

Accepts one of the following:

const BetaBashCodeExecutionToolResultErrorParamErrorCodeInvalidToolInput BetaBashCodeExecutionToolResultErrorParamErrorCode = "invalid_tool_input"

const BetaBashCodeExecutionToolResultErrorParamErrorCodeUnavailable BetaBashCodeExecutionToolResultErrorParamErrorCode = "unavailable"

const BetaBashCodeExecutionToolResultErrorParamErrorCodeTooManyRequests BetaBashCodeExecutionToolResultErrorParamErrorCode = "too_many_requests"

const BetaBashCodeExecutionToolResultErrorParamErrorCodeExecutionTimeExceeded BetaBashCodeExecutionToolResultErrorParamErrorCode = "execution_time_exceeded"

const BetaBashCodeExecutionToolResultErrorParamErrorCodeOutputFileTooLarge BetaBashCodeExecutionToolResultErrorParamErrorCode = "output_file_too_large"

Type BashCodeExecutionToolResultError

type BetaBashCodeExecutionResultBlockParamResp struct{…}

Content []BetaBashCodeExecutionOutputBlockParamResp

FileID string

Type BashCodeExecutionOutput

ReturnCode int64

Stderr string

Stdout string

Type BashCodeExecutionResult

ToolUseID string

Type BashCodeExecutionToolResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

type BetaTextEditorCodeExecutionToolResultBlockParamResp struct{…}

Content BetaTextEditorCodeExecutionToolResultBlockParamContentUnionResp

Accepts one of the following:

type BetaTextEditorCodeExecutionToolResultErrorParamResp struct{…}

ErrorCode BetaTextEditorCodeExecutionToolResultErrorParamErrorCode

Accepts one of the following:

const BetaTextEditorCodeExecutionToolResultErrorParamErrorCodeInvalidToolInput BetaTextEditorCodeExecutionToolResultErrorParamErrorCode = "invalid_tool_input"

const BetaTextEditorCodeExecutionToolResultErrorParamErrorCodeUnavailable BetaTextEditorCodeExecutionToolResultErrorParamErrorCode = "unavailable"

const BetaTextEditorCodeExecutionToolResultErrorParamErrorCodeTooManyRequests BetaTextEditorCodeExecutionToolResultErrorParamErrorCode = "too_many_requests"

const BetaTextEditorCodeExecutionToolResultErrorParamErrorCodeExecutionTimeExceeded BetaTextEditorCodeExecutionToolResultErrorParamErrorCode = "execution_time_exceeded"

const BetaTextEditorCodeExecutionToolResultErrorParamErrorCodeFileNotFound BetaTextEditorCodeExecutionToolResultErrorParamErrorCode = "file_not_found"

Type TextEditorCodeExecutionToolResultError

ErrorMessage stringoptional

type BetaTextEditorCodeExecutionViewResultBlockParamResp struct{…}

Content string

FileType BetaTextEditorCodeExecutionViewResultBlockParamFileType

Accepts one of the following:

const BetaTextEditorCodeExecutionViewResultBlockParamFileTypeText BetaTextEditorCodeExecutionViewResultBlockParamFileType = "text"

const BetaTextEditorCodeExecutionViewResultBlockParamFileTypeImage BetaTextEditorCodeExecutionViewResultBlockParamFileType = "image"

const BetaTextEditorCodeExecutionViewResultBlockParamFileTypePDF BetaTextEditorCodeExecutionViewResultBlockParamFileType = "pdf"

Type TextEditorCodeExecutionViewResult

NumLines int64optional

StartLine int64optional

TotalLines int64optional

type BetaTextEditorCodeExecutionCreateResultBlockParamResp struct{…}

IsFileUpdate bool

Type TextEditorCodeExecutionCreateResult

type BetaTextEditorCodeExecutionStrReplaceResultBlockParamResp struct{…}

Type TextEditorCodeExecutionStrReplaceResult

Lines []stringoptional

NewLines int64optional

NewStart int64optional

OldLines int64optional

OldStart int64optional

ToolUseID string

Type TextEditorCodeExecutionToolResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

type BetaToolSearchToolResultBlockParamResp struct{…}

Content BetaToolSearchToolResultBlockParamContentUnionResp

Accepts one of the following:

type BetaToolSearchToolResultErrorParamResp struct{…}

ErrorCode BetaToolSearchToolResultErrorParamErrorCode

Accepts one of the following:

const BetaToolSearchToolResultErrorParamErrorCodeInvalidToolInput BetaToolSearchToolResultErrorParamErrorCode = "invalid_tool_input"

const BetaToolSearchToolResultErrorParamErrorCodeUnavailable BetaToolSearchToolResultErrorParamErrorCode = "unavailable"

const BetaToolSearchToolResultErrorParamErrorCodeTooManyRequests BetaToolSearchToolResultErrorParamErrorCode = "too_many_requests"

const BetaToolSearchToolResultErrorParamErrorCodeExecutionTimeExceeded BetaToolSearchToolResultErrorParamErrorCode = "execution_time_exceeded"

Type ToolSearchToolResultError

type BetaToolSearchToolSearchResultBlockParamResp struct{…}

ToolReferences []BetaToolReferenceBlockParamResp

ToolName string

Type ToolReference

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Type ToolSearchToolSearchResult

ToolUseID string

Type ToolSearchToolResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

type BetaMCPToolUseBlockParamResp struct{…}

ID string

Input map[string, any]

Name string

ServerName string

The name of the MCP server

Type MCPToolUse

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

type BetaRequestMCPToolResultBlockParamResp struct{…}

ToolUseID string

Type MCPToolResult

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Content BetaRequestMCPToolResultBlockParamContentUnionRespoptional

Accepts one of the following:

string

[]BetaTextBlockParamResp

Text string

Type Text

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations []BetaTextCitationParamUnionRespoptional

Accepts one of the following:

type BetaCitationCharLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationWebSearchResultLocationParamResp struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocationParamResp struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

IsError booloptional

type BetaContainerUploadBlockParamResp struct{…}

A content block that represents a file to be uploaded to the container Files uploaded via this block will be available in the container's input directory.

FileID string

Type ContainerUpload

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

type BetaCompactionBlockParamResp struct{…}

A compaction block containing summary of previous context.

Users should round-trip these blocks from responses to subsequent requests to maintain context across compaction boundaries.

When content is None, the block represents a failed compaction. The server treats these as no-ops. Empty string content is not allowed.

Content string

Summary of previously compacted content, or null if compaction failed

Type Compaction

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Role BetaMessageParamRole

Accepts one of the following:

const BetaMessageParamRoleUser BetaMessageParamRole = "user"

const BetaMessageParamRoleAssistant BetaMessageParamRole = "assistant"

Model param.Field[Model]

Body param: The model that will complete your prompt.

See models for additional details and options.

CacheControl param.Field[BetaCacheControlEphemeral]optional

Body param: Top-level cache control automatically applies a cache_control marker to the last cacheable block in the request.

Container param.Field[BetaMessageNewParamsContainerUnion]optional

Body param: Container identifier for reuse across requests.

type BetaContainerParamsResp struct{…}

Container parameters with skills to be loaded.

ID stringoptional

Container id

Skills []BetaSkillParamsRespoptional

List of skills to load in the container

SkillID string

Skill ID

Type BetaSkillParamsType

Type of skill - either 'anthropic' (built-in) or 'custom' (user-defined)

Accepts one of the following:

const BetaSkillParamsTypeAnthropic BetaSkillParamsType = "anthropic"

const BetaSkillParamsTypeCustom BetaSkillParamsType = "custom"

Version stringoptional

Skill version or 'latest' for most recent version

string

ContextManagement param.Field[BetaContextManagementConfig]optional

Body param: Context management configuration.

This allows you to control how Claude manages context across multiple requests, such as whether to clear function results or not.

InferenceGeo param.Field[string]optional

Body param: Specifies the geographic region for inference processing. If not specified, the workspace's default_inference_geo is used.

MCPServers param.Field[[]BetaRequestMCPServerURLDefinition]optional

Body param: MCP servers to be utilized in this request

Name string

Type URL

URL string

AuthorizationToken stringoptional

ToolConfiguration BetaRequestMCPServerToolConfigurationoptional

AllowedTools []stringoptional

Enabled booloptional

Metadata param.Field[BetaMetadata]optional

Body param: An object describing metadata about the request.

OutputConfig param.Field[BetaOutputConfig]optional

Body param: Configuration options for the model's output, such as the output format.

DeprecatedOutputFormat param.Field[BetaJSONOutputFormat]optional

Body param: Deprecated: Use output_config.format instead. See structured outputs

A schema to specify Claude's output format in responses. This parameter will be removed in a future release.

ServiceTier param.Field[BetaMessageNewParamsServiceTier]optional

Body param: Determines whether to use priority capacity (if available) or standard capacity for this request.

Anthropic offers different levels of service for your API requests. See service-tiers for details.

const BetaMessageNewParamsServiceTierAuto BetaMessageNewParamsServiceTier = "auto"

const BetaMessageNewParamsServiceTierStandardOnly BetaMessageNewParamsServiceTier = "standard_only"

Speed param.Field[BetaMessageNewParamsSpeed]optional

Body param: The inference speed mode for this request. "fast" enables high output-tokens-per-second inference.

const BetaMessageNewParamsSpeedStandard BetaMessageNewParamsSpeed = "standard"

const BetaMessageNewParamsSpeedFast BetaMessageNewParamsSpeed = "fast"

StopSequences param.Field[[]string]optional

Body param: Custom text sequences that will cause the model to stop generating.

Our models will normally stop when they have naturally completed their turn, which will result in a response stop_reason of "end_turn".

If you want the model to stop generating when it encounters custom strings of text, you can use the stop_sequences parameter. If the model encounters one of the custom sequences, the response stop_reason value will be "stop_sequence" and the response stop_sequence value will contain the matched stop sequence.

System param.Field[[]BetaTextBlockParamResp]optional

Body param: System prompt.

A system prompt is a way of providing context and instructions to Claude, such as specifying a particular goal or role. See our guide to system prompts.

[]BetaTextBlockParam

Text string

Type Text

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations []BetaTextCitationParamUnionRespoptional

Accepts one of the following:

type BetaCitationCharLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocationParamResp struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationWebSearchResultLocationParamResp struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocationParamResp struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Temperature param.Field[float64]optional

Body param: Amount of randomness injected into the response.

Defaults to 1.0. Ranges from 0.0 to 1.0. Use temperature closer to 0.0 for analytical / multiple choice, and closer to 1.0 for creative and generative tasks.

Note that even with temperature of 0.0, the results will not be fully deterministic.

maximum1

minimum0

Thinking param.Field[BetaThinkingConfigParamUnionResp]optional

Body param: Configuration for enabling Claude's extended thinking.

When enabled, responses include thinking content blocks showing Claude's thinking process before the final answer. Requires a minimum budget of 1,024 tokens and counts towards your max_tokens limit.

See extended thinking for details.

ToolChoice param.Field[BetaToolChoiceUnion]optional

Body param: How the model should use the provided tools. The model can use a specific tool, any available tool, decide by itself, or not use tools at all.

Tools param.Field[[]BetaToolUnion]optional

Body param: Definitions of tools that the model may use.

If you include tools in your API request, the model may return tool_use content blocks that represent the model's use of those tools. You can then run those tools using the tool input generated by the model and then optionally return results back to the model using tool_result content blocks.

There are two types of tools: client tools and server tools. The behavior described below applies to client tools. For server tools, see their individual documentation as each has its own behavior (e.g., the web search tool).

Each tool definition includes:

name: Name of the tool.
description: Optional, but strongly-recommended description of the tool.
input_schema: JSON schema for the tool input shape that the model will produce in tool_use output content blocks.

For example, if you defined tools as:

[
  {
    "name": "get_stock_price",
    "description": "Get the current stock price for a given ticker symbol.",
    "input_schema": {
      "type": "object",
      "properties": {
        "ticker": {
          "type": "string",
          "description": "The stock ticker symbol, e.g. AAPL for Apple Inc."
        }
      },
      "required": ["ticker"]
    }
  }
]

And then asked the model "What's the S&P 500 at today?", the model might produce tool_use content blocks in the response like this:

[
  {
    "type": "tool_use",
    "id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
    "name": "get_stock_price",
    "input": { "ticker": "^GSPC" }
  }
]

You might then run your get_stock_price tool with {"ticker": "^GSPC"} as an input, and return the following back to the model in a subsequent user message:

[
  {
    "type": "tool_result",
    "tool_use_id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
    "content": "259.75 USD"
  }
]

Tools can be used for workflows that include running client-side tools and functions, or more generally whenever you want the model to produce a particular JSON structure of output.

See our guide for more details.

type BetaTool struct{…}

InputSchema BetaToolInputSchema

JSON schema for this tool's input.

This defines the shape of the input that your tool accepts and that the model will produce.

Type Object

Properties map[string, any]optional

Required []stringoptional

Name string

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

maxLength128

minLength1

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolAllowedCallerDirect BetaToolAllowedCaller = "direct"

const BetaToolAllowedCallerCodeExecution20250825 BetaToolAllowedCaller = "code_execution_20250825"

const BetaToolAllowedCallerCodeExecution20260120 BetaToolAllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

Description stringoptional

Description of what this tool does.

Tool descriptions should be as detailed as possible. The more information that the model has about what the tool is and how to use it, the better it will perform. You can use natural language descriptions to reinforce important aspects of the tool input JSON schema.

EagerInputStreaming booloptional

Enable eager input streaming for this tool. When true, tool input parameters will be streamed incrementally as they are generated, and types will be inferred on-the-fly rather than buffering the full JSON output. When false, streaming is disabled for this tool even if the fine-grained-tool-streaming beta is active. When null (default), uses the default behavior based on beta headers.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

Type BetaToolTypeoptional

type BetaToolBash20241022 struct{…}

Name Bash

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type Bash20241022

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolBash20241022AllowedCallerDirect BetaToolBash20241022AllowedCaller = "direct"

const BetaToolBash20241022AllowedCallerCodeExecution20250825 BetaToolBash20241022AllowedCaller = "code_execution_20250825"

const BetaToolBash20241022AllowedCallerCodeExecution20260120 BetaToolBash20241022AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolBash20250124 struct{…}

Name Bash

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type Bash20250124

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolBash20250124AllowedCallerDirect BetaToolBash20250124AllowedCaller = "direct"

const BetaToolBash20250124AllowedCallerCodeExecution20250825 BetaToolBash20250124AllowedCaller = "code_execution_20250825"

const BetaToolBash20250124AllowedCallerCodeExecution20260120 BetaToolBash20250124AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaCodeExecutionTool20250522 struct{…}

Name CodeExecution

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type CodeExecution20250522

AllowedCallers []stringoptional

Accepts one of the following:

const BetaCodeExecutionTool20250522AllowedCallerDirect BetaCodeExecutionTool20250522AllowedCaller = "direct"

const BetaCodeExecutionTool20250522AllowedCallerCodeExecution20250825 BetaCodeExecutionTool20250522AllowedCaller = "code_execution_20250825"

const BetaCodeExecutionTool20250522AllowedCallerCodeExecution20260120 BetaCodeExecutionTool20250522AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaCodeExecutionTool20250825 struct{…}

Name CodeExecution

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type CodeExecution20250825

AllowedCallers []stringoptional

Accepts one of the following:

const BetaCodeExecutionTool20250825AllowedCallerDirect BetaCodeExecutionTool20250825AllowedCaller = "direct"

const BetaCodeExecutionTool20250825AllowedCallerCodeExecution20250825 BetaCodeExecutionTool20250825AllowedCaller = "code_execution_20250825"

const BetaCodeExecutionTool20250825AllowedCallerCodeExecution20260120 BetaCodeExecutionTool20250825AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaCodeExecutionTool20260120 struct{…}

Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

Name CodeExecution

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type CodeExecution20260120

AllowedCallers []stringoptional

Accepts one of the following:

const BetaCodeExecutionTool20260120AllowedCallerDirect BetaCodeExecutionTool20260120AllowedCaller = "direct"

const BetaCodeExecutionTool20260120AllowedCallerCodeExecution20250825 BetaCodeExecutionTool20260120AllowedCaller = "code_execution_20250825"

const BetaCodeExecutionTool20260120AllowedCallerCodeExecution20260120 BetaCodeExecutionTool20260120AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolComputerUse20241022 struct{…}

DisplayHeightPx int64

The height of the display in pixels.

DisplayWidthPx int64

The width of the display in pixels.

Name Computer

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type Computer20241022

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolComputerUse20241022AllowedCallerDirect BetaToolComputerUse20241022AllowedCaller = "direct"

const BetaToolComputerUse20241022AllowedCallerCodeExecution20250825 BetaToolComputerUse20241022AllowedCaller = "code_execution_20250825"

const BetaToolComputerUse20241022AllowedCallerCodeExecution20260120 BetaToolComputerUse20241022AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

DisplayNumber int64optional

The X11 display number (e.g. 0, 1) for the display.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaMemoryTool20250818 struct{…}

Name Memory

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type Memory20250818

AllowedCallers []stringoptional

Accepts one of the following:

const BetaMemoryTool20250818AllowedCallerDirect BetaMemoryTool20250818AllowedCaller = "direct"

const BetaMemoryTool20250818AllowedCallerCodeExecution20250825 BetaMemoryTool20250818AllowedCaller = "code_execution_20250825"

const BetaMemoryTool20250818AllowedCallerCodeExecution20260120 BetaMemoryTool20250818AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolComputerUse20250124 struct{…}

DisplayHeightPx int64

The height of the display in pixels.

DisplayWidthPx int64

The width of the display in pixels.

Name Computer

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type Computer20250124

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolComputerUse20250124AllowedCallerDirect BetaToolComputerUse20250124AllowedCaller = "direct"

const BetaToolComputerUse20250124AllowedCallerCodeExecution20250825 BetaToolComputerUse20250124AllowedCaller = "code_execution_20250825"

const BetaToolComputerUse20250124AllowedCallerCodeExecution20260120 BetaToolComputerUse20250124AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

DisplayNumber int64optional

The X11 display number (e.g. 0, 1) for the display.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolTextEditor20241022 struct{…}

Name StrReplaceEditor

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type TextEditor20241022

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolTextEditor20241022AllowedCallerDirect BetaToolTextEditor20241022AllowedCaller = "direct"

const BetaToolTextEditor20241022AllowedCallerCodeExecution20250825 BetaToolTextEditor20241022AllowedCaller = "code_execution_20250825"

const BetaToolTextEditor20241022AllowedCallerCodeExecution20260120 BetaToolTextEditor20241022AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolComputerUse20251124 struct{…}

DisplayHeightPx int64

The height of the display in pixels.

DisplayWidthPx int64

The width of the display in pixels.

Name Computer

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type Computer20251124

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolComputerUse20251124AllowedCallerDirect BetaToolComputerUse20251124AllowedCaller = "direct"

const BetaToolComputerUse20251124AllowedCallerCodeExecution20250825 BetaToolComputerUse20251124AllowedCaller = "code_execution_20250825"

const BetaToolComputerUse20251124AllowedCallerCodeExecution20260120 BetaToolComputerUse20251124AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

DisplayNumber int64optional

The X11 display number (e.g. 0, 1) for the display.

EnableZoom booloptional

Whether to enable an action to take a zoomed-in screenshot of the screen.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolTextEditor20250124 struct{…}

Name StrReplaceEditor

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type TextEditor20250124

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolTextEditor20250124AllowedCallerDirect BetaToolTextEditor20250124AllowedCaller = "direct"

const BetaToolTextEditor20250124AllowedCallerCodeExecution20250825 BetaToolTextEditor20250124AllowedCaller = "code_execution_20250825"

const BetaToolTextEditor20250124AllowedCallerCodeExecution20260120 BetaToolTextEditor20250124AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolTextEditor20250429 struct{…}

Name StrReplaceBasedEditTool

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type TextEditor20250429

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolTextEditor20250429AllowedCallerDirect BetaToolTextEditor20250429AllowedCaller = "direct"

const BetaToolTextEditor20250429AllowedCallerCodeExecution20250825 BetaToolTextEditor20250429AllowedCaller = "code_execution_20250825"

const BetaToolTextEditor20250429AllowedCallerCodeExecution20260120 BetaToolTextEditor20250429AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

InputExamples []map[string, any]optional

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolTextEditor20250728 struct{…}

Name StrReplaceBasedEditTool

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type TextEditor20250728

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolTextEditor20250728AllowedCallerDirect BetaToolTextEditor20250728AllowedCaller = "direct"

const BetaToolTextEditor20250728AllowedCallerCodeExecution20250825 BetaToolTextEditor20250728AllowedCaller = "code_execution_20250825"

const BetaToolTextEditor20250728AllowedCallerCodeExecution20260120 BetaToolTextEditor20250728AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

InputExamples []map[string, any]optional

MaxCharacters int64optional

Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaWebSearchTool20250305 struct{…}

Name WebSearch

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type WebSearch20250305

AllowedCallers []stringoptional

Accepts one of the following:

const BetaWebSearchTool20250305AllowedCallerDirect BetaWebSearchTool20250305AllowedCaller = "direct"

const BetaWebSearchTool20250305AllowedCallerCodeExecution20250825 BetaWebSearchTool20250305AllowedCaller = "code_execution_20250825"

const BetaWebSearchTool20250305AllowedCallerCodeExecution20260120 BetaWebSearchTool20250305AllowedCaller = "code_execution_20260120"

AllowedDomains []stringoptional

If provided, only these domains will be included in results. Cannot be used alongside blocked_domains.

BlockedDomains []stringoptional

If provided, these domains will never appear in results. Cannot be used alongside allowed_domains.

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

MaxUses int64optional

Maximum number of times the tool can be used in the API request.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

UserLocation BetaUserLocationoptional

Parameters for the user's location. Used to provide more relevant search results.

Type Approximate

City stringoptional

The city of the user.

Country stringoptional

The two letter ISO country code of the user.

Region stringoptional

The region of the user.

Timezone stringoptional

The IANA timezone of the user.

type BetaWebFetchTool20250910 struct{…}

Name WebFetch

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type WebFetch20250910

AllowedCallers []stringoptional

Accepts one of the following:

const BetaWebFetchTool20250910AllowedCallerDirect BetaWebFetchTool20250910AllowedCaller = "direct"

const BetaWebFetchTool20250910AllowedCallerCodeExecution20250825 BetaWebFetchTool20250910AllowedCaller = "code_execution_20250825"

const BetaWebFetchTool20250910AllowedCallerCodeExecution20260120 BetaWebFetchTool20250910AllowedCaller = "code_execution_20260120"

AllowedDomains []stringoptional

List of domains to allow fetching from

BlockedDomains []stringoptional

List of domains to block fetching from

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations BetaCitationsConfigParamRespoptional

Citations configuration for fetched documents. Citations are disabled by default.

Enabled booloptional

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

MaxContentTokens int64optional

Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

MaxUses int64optional

Maximum number of times the tool can be used in the API request.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaWebSearchTool20260209 struct{…}

Name WebSearch

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type WebSearch20260209

AllowedCallers []stringoptional

Accepts one of the following:

const BetaWebSearchTool20260209AllowedCallerDirect BetaWebSearchTool20260209AllowedCaller = "direct"

const BetaWebSearchTool20260209AllowedCallerCodeExecution20250825 BetaWebSearchTool20260209AllowedCaller = "code_execution_20250825"

const BetaWebSearchTool20260209AllowedCallerCodeExecution20260120 BetaWebSearchTool20260209AllowedCaller = "code_execution_20260120"

AllowedDomains []stringoptional

If provided, only these domains will be included in results. Cannot be used alongside blocked_domains.

BlockedDomains []stringoptional

If provided, these domains will never appear in results. Cannot be used alongside allowed_domains.

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

MaxUses int64optional

Maximum number of times the tool can be used in the API request.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

UserLocation BetaUserLocationoptional

Parameters for the user's location. Used to provide more relevant search results.

Type Approximate

City stringoptional

The city of the user.

Country stringoptional

The two letter ISO country code of the user.

Region stringoptional

The region of the user.

Timezone stringoptional

The IANA timezone of the user.

type BetaWebFetchTool20260209 struct{…}

Name WebFetch

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type WebFetch20260209

AllowedCallers []stringoptional

Accepts one of the following:

const BetaWebFetchTool20260209AllowedCallerDirect BetaWebFetchTool20260209AllowedCaller = "direct"

const BetaWebFetchTool20260209AllowedCallerCodeExecution20250825 BetaWebFetchTool20260209AllowedCaller = "code_execution_20250825"

const BetaWebFetchTool20260209AllowedCallerCodeExecution20260120 BetaWebFetchTool20260209AllowedCaller = "code_execution_20260120"

AllowedDomains []stringoptional

List of domains to allow fetching from

BlockedDomains []stringoptional

List of domains to block fetching from

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Citations BetaCitationsConfigParamRespoptional

Citations configuration for fetched documents. Citations are disabled by default.

Enabled booloptional

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

MaxContentTokens int64optional

Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

MaxUses int64optional

Maximum number of times the tool can be used in the API request.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolSearchToolBm25_20251119 struct{…}

Name ToolSearchToolBm25

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type BetaToolSearchToolBm25_20251119Type

Accepts one of the following:

const BetaToolSearchToolBm25_20251119TypeToolSearchToolBm25_20251119 BetaToolSearchToolBm25_20251119Type = "tool_search_tool_bm25_20251119"

const BetaToolSearchToolBm25_20251119TypeToolSearchToolBm25 BetaToolSearchToolBm25_20251119Type = "tool_search_tool_bm25"

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolSearchToolBm25_20251119AllowedCallerDirect BetaToolSearchToolBm25_20251119AllowedCaller = "direct"

const BetaToolSearchToolBm25_20251119AllowedCallerCodeExecution20250825 BetaToolSearchToolBm25_20251119AllowedCaller = "code_execution_20250825"

const BetaToolSearchToolBm25_20251119AllowedCallerCodeExecution20260120 BetaToolSearchToolBm25_20251119AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaToolSearchToolRegex20251119 struct{…}

Name ToolSearchToolRegex

Name of the tool.

This is how the tool will be called by the model and in tool_use blocks.

Type BetaToolSearchToolRegex20251119Type

Accepts one of the following:

const BetaToolSearchToolRegex20251119TypeToolSearchToolRegex20251119 BetaToolSearchToolRegex20251119Type = "tool_search_tool_regex_20251119"

const BetaToolSearchToolRegex20251119TypeToolSearchToolRegex BetaToolSearchToolRegex20251119Type = "tool_search_tool_regex"

AllowedCallers []stringoptional

Accepts one of the following:

const BetaToolSearchToolRegex20251119AllowedCallerDirect BetaToolSearchToolRegex20251119AllowedCaller = "direct"

const BetaToolSearchToolRegex20251119AllowedCallerCodeExecution20250825 BetaToolSearchToolRegex20251119AllowedCaller = "code_execution_20250825"

const BetaToolSearchToolRegex20251119AllowedCallerCodeExecution20260120 BetaToolSearchToolRegex20251119AllowedCaller = "code_execution_20260120"

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

DeferLoading booloptional

If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

Strict booloptional

When true, guarantees schema validation on tool names and inputs

type BetaMCPToolset struct{…}

Configuration for a group of tools from an MCP server.

Allows configuring enabled status and defer_loading for all tools from an MCP server, with optional per-tool overrides.

MCPServerName string

Name of the MCP server to configure tools for

Type MCPToolset

CacheControl BetaCacheControlEphemeraloptional

Create a cache control breakpoint at this content block.

Type Ephemeral

TTL BetaCacheControlEphemeralTTLoptional

The time-to-live for the cache control breakpoint.

This may be one the following values:

5m: 5 minutes
1h: 1 hour

Defaults to 5m.

Accepts one of the following:

const BetaCacheControlEphemeralTTLTTL5m BetaCacheControlEphemeralTTL = "5m"

const BetaCacheControlEphemeralTTLTTL1h BetaCacheControlEphemeralTTL = "1h"

Configs map[string, BetaMCPToolConfig]optional

Configuration overrides for specific tools, keyed by tool name

DeferLoading booloptional

Enabled booloptional

DefaultConfig BetaMCPToolDefaultConfigoptional

Default configuration applied to all tools from this server

DeferLoading booloptional

Enabled booloptional

TopK param.Field[int64]optional

Body param: Only sample from the top K options for each subsequent token.

Used to remove "long tail" low probability responses. Learn more technical details here.

Recommended for advanced use cases only. You usually only need to use temperature.

minimum0

TopP param.Field[float64]optional

Body param: Use nucleus sampling.

In nucleus sampling, we compute the cumulative distribution over all the options for each subsequent token in decreasing probability order and cut it off once it reaches a particular probability specified by top_p. You should either alter temperature or top_p, but not both.

Recommended for advanced use cases only. You usually only need to use temperature.

maximum1

minimum0

Betas param.Field[[]AnthropicBeta]optional

Header param: Optional header to specify the beta version(s) you want to use.

string

type AnthropicBeta string

Accepts one of the following:

const AnthropicBetaMessageBatches2024_09_24 AnthropicBeta = "message-batches-2024-09-24"

const AnthropicBetaPromptCaching2024_07_31 AnthropicBeta = "prompt-caching-2024-07-31"

const AnthropicBetaComputerUse2024_10_22 AnthropicBeta = "computer-use-2024-10-22"

const AnthropicBetaComputerUse2025_01_24 AnthropicBeta = "computer-use-2025-01-24"

const AnthropicBetaPDFs2024_09_25 AnthropicBeta = "pdfs-2024-09-25"

const AnthropicBetaTokenCounting2024_11_01 AnthropicBeta = "token-counting-2024-11-01"

const AnthropicBetaTokenEfficientTools2025_02_19 AnthropicBeta = "token-efficient-tools-2025-02-19"

const AnthropicBetaOutput128k2025_02_19 AnthropicBeta = "output-128k-2025-02-19"

const AnthropicBetaFilesAPI2025_04_14 AnthropicBeta = "files-api-2025-04-14"

const AnthropicBetaMCPClient2025_04_04 AnthropicBeta = "mcp-client-2025-04-04"

const AnthropicBetaMCPClient2025_11_20 AnthropicBeta = "mcp-client-2025-11-20"

const AnthropicBetaDevFullThinking2025_05_14 AnthropicBeta = "dev-full-thinking-2025-05-14"

const AnthropicBetaInterleavedThinking2025_05_14 AnthropicBeta = "interleaved-thinking-2025-05-14"

const AnthropicBetaCodeExecution2025_05_22 AnthropicBeta = "code-execution-2025-05-22"

const AnthropicBetaExtendedCacheTTL2025_04_11 AnthropicBeta = "extended-cache-ttl-2025-04-11"

const AnthropicBetaContext1m2025_08_07 AnthropicBeta = "context-1m-2025-08-07"

const AnthropicBetaContextManagement2025_06_27 AnthropicBeta = "context-management-2025-06-27"

const AnthropicBetaModelContextWindowExceeded2025_08_26 AnthropicBeta = "model-context-window-exceeded-2025-08-26"

const AnthropicBetaSkills2025_10_02 AnthropicBeta = "skills-2025-10-02"

const AnthropicBetaFastMode2026_02_01 AnthropicBeta = "fast-mode-2026-02-01"

ReturnsExpand Collapse

type BetaMessage struct{…}

ID string

Unique object identifier.

The format and length of IDs may change over time.

Container BetaContainer

Information about the container used in the request (for the code execution tool)

ID string

Identifier for the container used in this request

ExpiresAt Time

The time at which the container will expire.

Skills []BetaSkill

Skills loaded in the container

SkillID string

Skill ID

Type BetaSkillType

Type of skill - either 'anthropic' (built-in) or 'custom' (user-defined)

Accepts one of the following:

const BetaSkillTypeAnthropic BetaSkillType = "anthropic"

const BetaSkillTypeCustom BetaSkillType = "custom"

Version string

Skill version or 'latest' for most recent version

Content []BetaContentBlockUnion

Content generated by the model.

This is an array of content blocks, each of which has a type that determines its shape.

Example:

[{"type": "text", "text": "Hi, I'm Claude."}]

If the request input messages ended with an assistant turn, then the response content will continue directly from that last turn. You can use this to constrain the model's output.

For example, if the input messages were:

[
  {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
  {"role": "assistant", "content": "The best answer is ("}
]

Then the response content might be:

[{"type": "text", "text": "B)"}]

Accepts one of the following:

type BetaTextBlock struct{…}

Citations []BetaTextCitationUnion

Citations supporting the text block.

The type of citation returned will depend on the type of document being cited. Citing a PDF results in page_location, plain text results in char_location, and content document results in content_block_location.

Accepts one of the following:

type BetaCitationCharLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

FileID string

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

FileID string

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

FileID string

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationsWebSearchResultLocation struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocation struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Text string

Type Text

type BetaThinkingBlock struct{…}

Signature string

Thinking string

Type Thinking

type BetaRedactedThinkingBlock struct{…}

Data string

Type RedactedThinking

type BetaToolUseBlock struct{…}

ID string

Input map[string, any]

Name string

Type ToolUse

Caller BetaToolUseBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaServerToolUseBlock struct{…}

ID string

Input map[string, any]

Name BetaServerToolUseBlockName

Accepts one of the following:

const BetaServerToolUseBlockNameWebSearch BetaServerToolUseBlockName = "web_search"

const BetaServerToolUseBlockNameWebFetch BetaServerToolUseBlockName = "web_fetch"

const BetaServerToolUseBlockNameCodeExecution BetaServerToolUseBlockName = "code_execution"

const BetaServerToolUseBlockNameBashCodeExecution BetaServerToolUseBlockName = "bash_code_execution"

const BetaServerToolUseBlockNameTextEditorCodeExecution BetaServerToolUseBlockName = "text_editor_code_execution"

const BetaServerToolUseBlockNameToolSearchToolRegex BetaServerToolUseBlockName = "tool_search_tool_regex"

const BetaServerToolUseBlockNameToolSearchToolBm25 BetaServerToolUseBlockName = "tool_search_tool_bm25"

Type ServerToolUse

Caller BetaServerToolUseBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaWebSearchToolResultBlock struct{…}

Content BetaWebSearchToolResultBlockContentUnion

Accepts one of the following:

type BetaWebSearchToolResultError struct{…}

ErrorCode BetaWebSearchToolResultErrorCode

Accepts one of the following:

const BetaWebSearchToolResultErrorCodeInvalidToolInput BetaWebSearchToolResultErrorCode = "invalid_tool_input"

const BetaWebSearchToolResultErrorCodeUnavailable BetaWebSearchToolResultErrorCode = "unavailable"

const BetaWebSearchToolResultErrorCodeMaxUsesExceeded BetaWebSearchToolResultErrorCode = "max_uses_exceeded"

const BetaWebSearchToolResultErrorCodeTooManyRequests BetaWebSearchToolResultErrorCode = "too_many_requests"

const BetaWebSearchToolResultErrorCodeQueryTooLong BetaWebSearchToolResultErrorCode = "query_too_long"

const BetaWebSearchToolResultErrorCodeRequestTooLarge BetaWebSearchToolResultErrorCode = "request_too_large"

Type WebSearchToolResultError

type BetaWebSearchToolResultBlockContentArray []BetaWebSearchResultBlock

EncryptedContent string

PageAge string

Title string

Type WebSearchResult

URL string

ToolUseID string

Type WebSearchToolResult

Caller BetaWebSearchToolResultBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaWebFetchToolResultBlock struct{…}

Content BetaWebFetchToolResultBlockContentUnion

Accepts one of the following:

type BetaWebFetchToolResultErrorBlock struct{…}

ErrorCode BetaWebFetchToolResultErrorCode

Accepts one of the following:

const BetaWebFetchToolResultErrorCodeInvalidToolInput BetaWebFetchToolResultErrorCode = "invalid_tool_input"

const BetaWebFetchToolResultErrorCodeURLTooLong BetaWebFetchToolResultErrorCode = "url_too_long"

const BetaWebFetchToolResultErrorCodeURLNotAllowed BetaWebFetchToolResultErrorCode = "url_not_allowed"

const BetaWebFetchToolResultErrorCodeURLNotAccessible BetaWebFetchToolResultErrorCode = "url_not_accessible"

const BetaWebFetchToolResultErrorCodeUnsupportedContentType BetaWebFetchToolResultErrorCode = "unsupported_content_type"

const BetaWebFetchToolResultErrorCodeTooManyRequests BetaWebFetchToolResultErrorCode = "too_many_requests"

const BetaWebFetchToolResultErrorCodeMaxUsesExceeded BetaWebFetchToolResultErrorCode = "max_uses_exceeded"

const BetaWebFetchToolResultErrorCodeUnavailable BetaWebFetchToolResultErrorCode = "unavailable"

Type WebFetchToolResultError

type BetaWebFetchBlock struct{…}

Content BetaDocumentBlock

Citations BetaCitationConfig

Citation configuration for the document

Enabled bool

Source BetaDocumentBlockSourceUnion

Accepts one of the following:

type BetaBase64PDFSource struct{…}

Data string

MediaType ApplicationPDF

Type Base64

type BetaPlainTextSource struct{…}

Data string

MediaType TextPlain

Type Text

Title string

The title of the document

Type Document

RetrievedAt string

ISO 8601 timestamp when the content was retrieved

Type WebFetchResult

URL string

Fetched content URL

ToolUseID string

Type WebFetchToolResult

Caller BetaWebFetchToolResultBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaCodeExecutionToolResultBlock struct{…}

Content BetaCodeExecutionToolResultBlockContentUnion

Code execution result with encrypted stdout for PFC + web_search results.

Accepts one of the following:

type BetaCodeExecutionToolResultError struct{…}

ErrorCode BetaCodeExecutionToolResultErrorCode

Accepts one of the following:

const BetaCodeExecutionToolResultErrorCodeInvalidToolInput BetaCodeExecutionToolResultErrorCode = "invalid_tool_input"

const BetaCodeExecutionToolResultErrorCodeUnavailable BetaCodeExecutionToolResultErrorCode = "unavailable"

const BetaCodeExecutionToolResultErrorCodeTooManyRequests BetaCodeExecutionToolResultErrorCode = "too_many_requests"

const BetaCodeExecutionToolResultErrorCodeExecutionTimeExceeded BetaCodeExecutionToolResultErrorCode = "execution_time_exceeded"

Type CodeExecutionToolResultError

type BetaCodeExecutionResultBlock struct{…}

Content []BetaCodeExecutionOutputBlock

FileID string

Type CodeExecutionOutput

ReturnCode int64

Stderr string

Stdout string

Type CodeExecutionResult

type BetaEncryptedCodeExecutionResultBlock struct{…}

Code execution result with encrypted stdout for PFC + web_search results.

Content []BetaCodeExecutionOutputBlock

FileID string

Type CodeExecutionOutput

EncryptedStdout string

ReturnCode int64

Stderr string

Type EncryptedCodeExecutionResult

ToolUseID string

Type CodeExecutionToolResult

type BetaBashCodeExecutionToolResultBlock struct{…}

Content BetaBashCodeExecutionToolResultBlockContentUnion

Accepts one of the following:

type BetaBashCodeExecutionToolResultError struct{…}

ErrorCode BetaBashCodeExecutionToolResultErrorErrorCode

Accepts one of the following:

const BetaBashCodeExecutionToolResultErrorErrorCodeInvalidToolInput BetaBashCodeExecutionToolResultErrorErrorCode = "invalid_tool_input"

const BetaBashCodeExecutionToolResultErrorErrorCodeUnavailable BetaBashCodeExecutionToolResultErrorErrorCode = "unavailable"

const BetaBashCodeExecutionToolResultErrorErrorCodeTooManyRequests BetaBashCodeExecutionToolResultErrorErrorCode = "too_many_requests"

const BetaBashCodeExecutionToolResultErrorErrorCodeExecutionTimeExceeded BetaBashCodeExecutionToolResultErrorErrorCode = "execution_time_exceeded"

const BetaBashCodeExecutionToolResultErrorErrorCodeOutputFileTooLarge BetaBashCodeExecutionToolResultErrorErrorCode = "output_file_too_large"

Type BashCodeExecutionToolResultError

type BetaBashCodeExecutionResultBlock struct{…}

Content []BetaBashCodeExecutionOutputBlock

FileID string

Type BashCodeExecutionOutput

ReturnCode int64

Stderr string

Stdout string

Type BashCodeExecutionResult

ToolUseID string

Type BashCodeExecutionToolResult

type BetaTextEditorCodeExecutionToolResultBlock struct{…}

Content BetaTextEditorCodeExecutionToolResultBlockContentUnion

Accepts one of the following:

type BetaTextEditorCodeExecutionToolResultError struct{…}

ErrorCode BetaTextEditorCodeExecutionToolResultErrorErrorCode

Accepts one of the following:

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeInvalidToolInput BetaTextEditorCodeExecutionToolResultErrorErrorCode = "invalid_tool_input"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeUnavailable BetaTextEditorCodeExecutionToolResultErrorErrorCode = "unavailable"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeTooManyRequests BetaTextEditorCodeExecutionToolResultErrorErrorCode = "too_many_requests"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeExecutionTimeExceeded BetaTextEditorCodeExecutionToolResultErrorErrorCode = "execution_time_exceeded"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeFileNotFound BetaTextEditorCodeExecutionToolResultErrorErrorCode = "file_not_found"

ErrorMessage string

Type TextEditorCodeExecutionToolResultError

type BetaTextEditorCodeExecutionViewResultBlock struct{…}

Content string

FileType BetaTextEditorCodeExecutionViewResultBlockFileType

Accepts one of the following:

const BetaTextEditorCodeExecutionViewResultBlockFileTypeText BetaTextEditorCodeExecutionViewResultBlockFileType = "text"

const BetaTextEditorCodeExecutionViewResultBlockFileTypeImage BetaTextEditorCodeExecutionViewResultBlockFileType = "image"

const BetaTextEditorCodeExecutionViewResultBlockFileTypePDF BetaTextEditorCodeExecutionViewResultBlockFileType = "pdf"

NumLines int64

StartLine int64

TotalLines int64

Type TextEditorCodeExecutionViewResult

type BetaTextEditorCodeExecutionCreateResultBlock struct{…}

IsFileUpdate bool

Type TextEditorCodeExecutionCreateResult

type BetaTextEditorCodeExecutionStrReplaceResultBlock struct{…}

Lines []string

NewLines int64

NewStart int64

OldLines int64

OldStart int64

Type TextEditorCodeExecutionStrReplaceResult

ToolUseID string

Type TextEditorCodeExecutionToolResult

type BetaToolSearchToolResultBlock struct{…}

Content BetaToolSearchToolResultBlockContentUnion

Accepts one of the following:

type BetaToolSearchToolResultError struct{…}

ErrorCode BetaToolSearchToolResultErrorErrorCode

Accepts one of the following:

const BetaToolSearchToolResultErrorErrorCodeInvalidToolInput BetaToolSearchToolResultErrorErrorCode = "invalid_tool_input"

const BetaToolSearchToolResultErrorErrorCodeUnavailable BetaToolSearchToolResultErrorErrorCode = "unavailable"

const BetaToolSearchToolResultErrorErrorCodeTooManyRequests BetaToolSearchToolResultErrorErrorCode = "too_many_requests"

const BetaToolSearchToolResultErrorErrorCodeExecutionTimeExceeded BetaToolSearchToolResultErrorErrorCode = "execution_time_exceeded"

ErrorMessage string

Type ToolSearchToolResultError

type BetaToolSearchToolSearchResultBlock struct{…}

ToolReferences []BetaToolReferenceBlock

ToolName string

Type ToolReference

Type ToolSearchToolSearchResult

ToolUseID string

Type ToolSearchToolResult

type BetaMCPToolUseBlock struct{…}

ID string

Input map[string, any]

Name string

The name of the MCP tool

ServerName string

The name of the MCP server

Type MCPToolUse

type BetaMCPToolResultBlock struct{…}

Content BetaMCPToolResultBlockContentUnion

Accepts one of the following:

string

type BetaMCPToolResultBlockContentBetaMCPToolResultBlockContent []BetaTextBlock

Citations []BetaTextCitationUnion

Citations supporting the text block.

Accepts one of the following:

type BetaCitationCharLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

FileID string

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

FileID string

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

FileID string

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationsWebSearchResultLocation struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocation struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Text string

Type Text

IsError bool

ToolUseID string

Type MCPToolResult

type BetaContainerUploadBlock struct{…}

Response model for a file uploaded to the container.

FileID string

Type ContainerUpload

type BetaCompactionBlock struct{…}

A compaction block returned when autocompact is triggered.

When content is None, it indicates the compaction failed to produce a valid summary (e.g., malformed output from the model). Clients may round-trip compaction blocks with null content; the server treats them as no-ops.

Content string

Summary of compacted content, or null if compaction failed

Type Compaction

ContextManagement BetaContextManagementResponse

Context management response.

Information about context management strategies applied during the request.

AppliedEdits []BetaContextManagementResponseAppliedEditUnion

List of context management edits that were applied.

Accepts one of the following:

type BetaClearToolUses20250919EditResponse struct{…}

ClearedInputTokens int64

Number of input tokens cleared by this edit.

ClearedToolUses int64

Number of tool uses that were cleared.

Type ClearToolUses20250919

The type of context management edit applied.

type BetaClearThinking20251015EditResponse struct{…}

ClearedInputTokens int64

Number of input tokens cleared by this edit.

ClearedThinkingTurns int64

Number of thinking turns that were cleared.

Type ClearThinking20251015

The type of context management edit applied.

Model Model

The model that will complete your prompt.

See models for additional details and options.

Accepts one of the following:

type Model string

The model that will complete your prompt.

See models for additional details and options.

Accepts one of the following:

const ModelClaudeOpus4_6 Model = "claude-opus-4-6"

Most intelligent model for building agents and coding

const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"

Frontier intelligence at scale — built for coding, agents, and enterprise workflows

const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"

Premium model combining maximum intelligence with practical performance

const ModelClaudeOpus4_5 Model = "claude-opus-4-5"

Premium model combining maximum intelligence with practical performance

const ModelClaude3_7SonnetLatest Model = "claude-3-7-sonnet-latest"

High-performance model with early extended thinking

const ModelClaude3_7Sonnet20250219 Model = "claude-3-7-sonnet-20250219"

High-performance model with early extended thinking

const ModelClaude3_5HaikuLatest Model = "claude-3-5-haiku-latest"

Fastest and most compact model for near-instant responsiveness

const ModelClaude3_5Haiku20241022 Model = "claude-3-5-haiku-20241022"

Our fastest model

const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"

Hybrid model, capable of near-instant responses and extended thinking

const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"

Hybrid model, capable of near-instant responses and extended thinking

const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"

High-performance model with extended thinking

const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"

High-performance model with extended thinking

const ModelClaude4Sonnet20250514 Model = "claude-4-sonnet-20250514"

High-performance model with extended thinking

const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"

Our best model for real-world agents and coding

const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"

Our best model for real-world agents and coding

const ModelClaudeOpus4_0 Model = "claude-opus-4-0"

Our most capable model

const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"

Our most capable model

const ModelClaude4Opus20250514 Model = "claude-4-opus-20250514"

Our most capable model

const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"

Our most capable model

const ModelClaude3OpusLatest Model = "claude-3-opus-latest"

Excels at writing and complex tasks

const ModelClaude_3_Opus_20240229 Model = "claude-3-opus-20240229"

Excels at writing and complex tasks

const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"

Our previous most fast and cost-effective

string

Role Assistant

Conversational role of the generated message.

This will always be "assistant".

StopReason BetaStopReason

The reason that we stopped.

This may be one the following values:

"end_turn": the model reached a natural stopping point
"max_tokens": we exceeded the requested max_tokens or the model's maximum
"stop_sequence": one of your provided custom stop_sequences was generated
"tool_use": the model invoked one or more tools
"pause_turn": we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
"refusal": when streaming classifiers intervene to handle potential policy violations

In non-streaming mode this value is always non-null. In streaming mode, it is null in the message_start event and non-null otherwise.

Accepts one of the following:

const BetaStopReasonEndTurn BetaStopReason = "end_turn"

const BetaStopReasonMaxTokens BetaStopReason = "max_tokens"

const BetaStopReasonStopSequence BetaStopReason = "stop_sequence"

const BetaStopReasonToolUse BetaStopReason = "tool_use"

const BetaStopReasonPauseTurn BetaStopReason = "pause_turn"

const BetaStopReasonCompaction BetaStopReason = "compaction"

const BetaStopReasonRefusal BetaStopReason = "refusal"

const BetaStopReasonModelContextWindowExceeded BetaStopReason = "model_context_window_exceeded"

StopSequence string

Which custom stop sequence was generated, if any.

This value will be a non-null string if one of your custom stop sequences was generated.

Type Message

Object type.

For Messages, this is always "message".

Usage BetaUsage

Billing and rate-limit usage.

Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in usage will not match one-to-one with the exact visible content of an API request or response.

For example, output_tokens will be non-zero, even for an empty string response from Claude.

Total input tokens in a request is the summation of input_tokens, cache_creation_input_tokens, and cache_read_input_tokens.

CacheCreation BetaCacheCreation

Breakdown of cached tokens by TTL

Ephemeral1hInputTokens int64

The number of input tokens used to create the 1 hour cache entry.

Ephemeral5mInputTokens int64

The number of input tokens used to create the 5 minute cache entry.

CacheCreationInputTokens int64

The number of input tokens used to create the cache entry.

CacheReadInputTokens int64

The number of input tokens read from the cache.

InferenceGeo string

The geographic region where inference was performed for this request.

InputTokens int64

The number of input tokens which were used.

Iterations BetaIterationsUsage

Per-iteration token usage breakdown.

Each entry represents one sampling iteration, with its own input/output token counts and cache statistics. This allows you to:

Determine which iterations exceeded long context thresholds (>=200k tokens)
Calculate the true context window size from the last iteration
Understand token accumulation across server-side tool use loops

Accepts one of the following:

type BetaMessageIterationUsage struct{…}

Token usage for a sampling iteration.

CacheCreation BetaCacheCreation

Breakdown of cached tokens by TTL

Ephemeral1hInputTokens int64

The number of input tokens used to create the 1 hour cache entry.

Ephemeral5mInputTokens int64

The number of input tokens used to create the 5 minute cache entry.

CacheCreationInputTokens int64

The number of input tokens used to create the cache entry.

CacheReadInputTokens int64

The number of input tokens read from the cache.

InputTokens int64

The number of input tokens which were used.

OutputTokens int64

The number of output tokens which were used.

Type Message

Usage for a sampling iteration

type BetaCompactionIterationUsage struct{…}

Token usage for a compaction iteration.

CacheCreation BetaCacheCreation

Breakdown of cached tokens by TTL

Ephemeral1hInputTokens int64

The number of input tokens used to create the 1 hour cache entry.

Ephemeral5mInputTokens int64

The number of input tokens used to create the 5 minute cache entry.

CacheCreationInputTokens int64

The number of input tokens used to create the cache entry.

CacheReadInputTokens int64

The number of input tokens read from the cache.

InputTokens int64

The number of input tokens which were used.

OutputTokens int64

The number of output tokens which were used.

Type Compaction

Usage for a compaction iteration

OutputTokens int64

The number of output tokens which were used.

ServerToolUse BetaServerToolUsage

The number of server tool requests.

WebFetchRequests int64

The number of web fetch tool requests.

WebSearchRequests int64

The number of web search tool requests.

ServiceTier BetaUsageServiceTier

If the request used the priority, standard, or batch tier.

Accepts one of the following:

const BetaUsageServiceTierStandard BetaUsageServiceTier = "standard"

const BetaUsageServiceTierPriority BetaUsageServiceTier = "priority"

const BetaUsageServiceTierBatch BetaUsageServiceTier = "batch"

Speed BetaUsageSpeed

The inference speed mode used for this request.

Accepts one of the following:

const BetaUsageSpeedStandard BetaUsageSpeed = "standard"

const BetaUsageSpeedFast BetaUsageSpeed = "fast"

type BetaRawMessageStreamEventUnion interface{…}

Accepts one of the following:

type BetaRawMessageStartEvent struct{…}

Message BetaMessage

ID string

Unique object identifier.

The format and length of IDs may change over time.

Container BetaContainer

Information about the container used in the request (for the code execution tool)

ID string

Identifier for the container used in this request

ExpiresAt Time

The time at which the container will expire.

Skills []BetaSkill

Skills loaded in the container

SkillID string

Skill ID

Type BetaSkillType

Type of skill - either 'anthropic' (built-in) or 'custom' (user-defined)

Accepts one of the following:

const BetaSkillTypeAnthropic BetaSkillType = "anthropic"

const BetaSkillTypeCustom BetaSkillType = "custom"

Version string

Skill version or 'latest' for most recent version

Content []BetaContentBlockUnion

Content generated by the model.

This is an array of content blocks, each of which has a type that determines its shape.

Example:

[{"type": "text", "text": "Hi, I'm Claude."}]

If the request input messages ended with an assistant turn, then the response content will continue directly from that last turn. You can use this to constrain the model's output.

For example, if the input messages were:

[
  {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
  {"role": "assistant", "content": "The best answer is ("}
]

Then the response content might be:

[{"type": "text", "text": "B)"}]

Accepts one of the following:

type BetaTextBlock struct{…}

Citations []BetaTextCitationUnion

Citations supporting the text block.

Accepts one of the following:

type BetaCitationCharLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

FileID string

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

FileID string

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

FileID string

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationsWebSearchResultLocation struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocation struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Text string

Type Text

type BetaThinkingBlock struct{…}

Signature string

Thinking string

Type Thinking

type BetaRedactedThinkingBlock struct{…}

Data string

Type RedactedThinking

type BetaToolUseBlock struct{…}

ID string

Input map[string, any]

Name string

Type ToolUse

Caller BetaToolUseBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaServerToolUseBlock struct{…}

ID string

Input map[string, any]

Name BetaServerToolUseBlockName

Accepts one of the following:

const BetaServerToolUseBlockNameWebSearch BetaServerToolUseBlockName = "web_search"

const BetaServerToolUseBlockNameWebFetch BetaServerToolUseBlockName = "web_fetch"

const BetaServerToolUseBlockNameCodeExecution BetaServerToolUseBlockName = "code_execution"

const BetaServerToolUseBlockNameBashCodeExecution BetaServerToolUseBlockName = "bash_code_execution"

const BetaServerToolUseBlockNameTextEditorCodeExecution BetaServerToolUseBlockName = "text_editor_code_execution"

const BetaServerToolUseBlockNameToolSearchToolRegex BetaServerToolUseBlockName = "tool_search_tool_regex"

const BetaServerToolUseBlockNameToolSearchToolBm25 BetaServerToolUseBlockName = "tool_search_tool_bm25"

Type ServerToolUse

Caller BetaServerToolUseBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaWebSearchToolResultBlock struct{…}

Content BetaWebSearchToolResultBlockContentUnion

Accepts one of the following:

type BetaWebSearchToolResultError struct{…}

ErrorCode BetaWebSearchToolResultErrorCode

Accepts one of the following:

const BetaWebSearchToolResultErrorCodeInvalidToolInput BetaWebSearchToolResultErrorCode = "invalid_tool_input"

const BetaWebSearchToolResultErrorCodeUnavailable BetaWebSearchToolResultErrorCode = "unavailable"

const BetaWebSearchToolResultErrorCodeMaxUsesExceeded BetaWebSearchToolResultErrorCode = "max_uses_exceeded"

const BetaWebSearchToolResultErrorCodeTooManyRequests BetaWebSearchToolResultErrorCode = "too_many_requests"

const BetaWebSearchToolResultErrorCodeQueryTooLong BetaWebSearchToolResultErrorCode = "query_too_long"

const BetaWebSearchToolResultErrorCodeRequestTooLarge BetaWebSearchToolResultErrorCode = "request_too_large"

Type WebSearchToolResultError

type BetaWebSearchToolResultBlockContentArray []BetaWebSearchResultBlock

EncryptedContent string

PageAge string

Title string

Type WebSearchResult

URL string

ToolUseID string

Type WebSearchToolResult

Caller BetaWebSearchToolResultBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaWebFetchToolResultBlock struct{…}

Content BetaWebFetchToolResultBlockContentUnion

Accepts one of the following:

type BetaWebFetchToolResultErrorBlock struct{…}

ErrorCode BetaWebFetchToolResultErrorCode

Accepts one of the following:

const BetaWebFetchToolResultErrorCodeInvalidToolInput BetaWebFetchToolResultErrorCode = "invalid_tool_input"

const BetaWebFetchToolResultErrorCodeURLTooLong BetaWebFetchToolResultErrorCode = "url_too_long"

const BetaWebFetchToolResultErrorCodeURLNotAllowed BetaWebFetchToolResultErrorCode = "url_not_allowed"

const BetaWebFetchToolResultErrorCodeURLNotAccessible BetaWebFetchToolResultErrorCode = "url_not_accessible"

const BetaWebFetchToolResultErrorCodeUnsupportedContentType BetaWebFetchToolResultErrorCode = "unsupported_content_type"

const BetaWebFetchToolResultErrorCodeTooManyRequests BetaWebFetchToolResultErrorCode = "too_many_requests"

const BetaWebFetchToolResultErrorCodeMaxUsesExceeded BetaWebFetchToolResultErrorCode = "max_uses_exceeded"

const BetaWebFetchToolResultErrorCodeUnavailable BetaWebFetchToolResultErrorCode = "unavailable"

Type WebFetchToolResultError

type BetaWebFetchBlock struct{…}

Content BetaDocumentBlock

Citations BetaCitationConfig

Citation configuration for the document

Enabled bool

Source BetaDocumentBlockSourceUnion

Accepts one of the following:

type BetaBase64PDFSource struct{…}

Data string

MediaType ApplicationPDF

Type Base64

type BetaPlainTextSource struct{…}

Data string

MediaType TextPlain

Type Text

Title string

The title of the document

Type Document

RetrievedAt string

ISO 8601 timestamp when the content was retrieved

Type WebFetchResult

URL string

Fetched content URL

ToolUseID string

Type WebFetchToolResult

Caller BetaWebFetchToolResultBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaCodeExecutionToolResultBlock struct{…}

Content BetaCodeExecutionToolResultBlockContentUnion

Code execution result with encrypted stdout for PFC + web_search results.

Accepts one of the following:

type BetaCodeExecutionToolResultError struct{…}

ErrorCode BetaCodeExecutionToolResultErrorCode

Accepts one of the following:

const BetaCodeExecutionToolResultErrorCodeInvalidToolInput BetaCodeExecutionToolResultErrorCode = "invalid_tool_input"

const BetaCodeExecutionToolResultErrorCodeUnavailable BetaCodeExecutionToolResultErrorCode = "unavailable"

const BetaCodeExecutionToolResultErrorCodeTooManyRequests BetaCodeExecutionToolResultErrorCode = "too_many_requests"

const BetaCodeExecutionToolResultErrorCodeExecutionTimeExceeded BetaCodeExecutionToolResultErrorCode = "execution_time_exceeded"

Type CodeExecutionToolResultError

type BetaCodeExecutionResultBlock struct{…}

Content []BetaCodeExecutionOutputBlock

FileID string

Type CodeExecutionOutput

ReturnCode int64

Stderr string

Stdout string

Type CodeExecutionResult

type BetaEncryptedCodeExecutionResultBlock struct{…}

Code execution result with encrypted stdout for PFC + web_search results.

Content []BetaCodeExecutionOutputBlock

FileID string

Type CodeExecutionOutput

EncryptedStdout string

ReturnCode int64

Stderr string

Type EncryptedCodeExecutionResult

ToolUseID string

Type CodeExecutionToolResult

type BetaBashCodeExecutionToolResultBlock struct{…}

Content BetaBashCodeExecutionToolResultBlockContentUnion

Accepts one of the following:

type BetaBashCodeExecutionToolResultError struct{…}

ErrorCode BetaBashCodeExecutionToolResultErrorErrorCode

Accepts one of the following:

const BetaBashCodeExecutionToolResultErrorErrorCodeInvalidToolInput BetaBashCodeExecutionToolResultErrorErrorCode = "invalid_tool_input"

const BetaBashCodeExecutionToolResultErrorErrorCodeUnavailable BetaBashCodeExecutionToolResultErrorErrorCode = "unavailable"

const BetaBashCodeExecutionToolResultErrorErrorCodeTooManyRequests BetaBashCodeExecutionToolResultErrorErrorCode = "too_many_requests"

const BetaBashCodeExecutionToolResultErrorErrorCodeExecutionTimeExceeded BetaBashCodeExecutionToolResultErrorErrorCode = "execution_time_exceeded"

const BetaBashCodeExecutionToolResultErrorErrorCodeOutputFileTooLarge BetaBashCodeExecutionToolResultErrorErrorCode = "output_file_too_large"

Type BashCodeExecutionToolResultError

type BetaBashCodeExecutionResultBlock struct{…}

Content []BetaBashCodeExecutionOutputBlock

FileID string

Type BashCodeExecutionOutput

ReturnCode int64

Stderr string

Stdout string

Type BashCodeExecutionResult

ToolUseID string

Type BashCodeExecutionToolResult

type BetaTextEditorCodeExecutionToolResultBlock struct{…}

Content BetaTextEditorCodeExecutionToolResultBlockContentUnion

Accepts one of the following:

type BetaTextEditorCodeExecutionToolResultError struct{…}

ErrorCode BetaTextEditorCodeExecutionToolResultErrorErrorCode

Accepts one of the following:

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeInvalidToolInput BetaTextEditorCodeExecutionToolResultErrorErrorCode = "invalid_tool_input"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeUnavailable BetaTextEditorCodeExecutionToolResultErrorErrorCode = "unavailable"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeTooManyRequests BetaTextEditorCodeExecutionToolResultErrorErrorCode = "too_many_requests"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeExecutionTimeExceeded BetaTextEditorCodeExecutionToolResultErrorErrorCode = "execution_time_exceeded"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeFileNotFound BetaTextEditorCodeExecutionToolResultErrorErrorCode = "file_not_found"

ErrorMessage string

Type TextEditorCodeExecutionToolResultError

type BetaTextEditorCodeExecutionViewResultBlock struct{…}

Content string

FileType BetaTextEditorCodeExecutionViewResultBlockFileType

Accepts one of the following:

const BetaTextEditorCodeExecutionViewResultBlockFileTypeText BetaTextEditorCodeExecutionViewResultBlockFileType = "text"

const BetaTextEditorCodeExecutionViewResultBlockFileTypeImage BetaTextEditorCodeExecutionViewResultBlockFileType = "image"

const BetaTextEditorCodeExecutionViewResultBlockFileTypePDF BetaTextEditorCodeExecutionViewResultBlockFileType = "pdf"

NumLines int64

StartLine int64

TotalLines int64

Type TextEditorCodeExecutionViewResult

type BetaTextEditorCodeExecutionCreateResultBlock struct{…}

IsFileUpdate bool

Type TextEditorCodeExecutionCreateResult

type BetaTextEditorCodeExecutionStrReplaceResultBlock struct{…}

Lines []string

NewLines int64

NewStart int64

OldLines int64

OldStart int64

Type TextEditorCodeExecutionStrReplaceResult

ToolUseID string

Type TextEditorCodeExecutionToolResult

type BetaToolSearchToolResultBlock struct{…}

Content BetaToolSearchToolResultBlockContentUnion

Accepts one of the following:

type BetaToolSearchToolResultError struct{…}

ErrorCode BetaToolSearchToolResultErrorErrorCode

Accepts one of the following:

const BetaToolSearchToolResultErrorErrorCodeInvalidToolInput BetaToolSearchToolResultErrorErrorCode = "invalid_tool_input"

const BetaToolSearchToolResultErrorErrorCodeUnavailable BetaToolSearchToolResultErrorErrorCode = "unavailable"

const BetaToolSearchToolResultErrorErrorCodeTooManyRequests BetaToolSearchToolResultErrorErrorCode = "too_many_requests"

const BetaToolSearchToolResultErrorErrorCodeExecutionTimeExceeded BetaToolSearchToolResultErrorErrorCode = "execution_time_exceeded"

ErrorMessage string

Type ToolSearchToolResultError

type BetaToolSearchToolSearchResultBlock struct{…}

ToolReferences []BetaToolReferenceBlock

ToolName string

Type ToolReference

Type ToolSearchToolSearchResult

ToolUseID string

Type ToolSearchToolResult

type BetaMCPToolUseBlock struct{…}

ID string

Input map[string, any]

Name string

The name of the MCP tool

ServerName string

The name of the MCP server

Type MCPToolUse

type BetaMCPToolResultBlock struct{…}

Content BetaMCPToolResultBlockContentUnion

Accepts one of the following:

string

type BetaMCPToolResultBlockContentBetaMCPToolResultBlockContent []BetaTextBlock

Citations []BetaTextCitationUnion

Citations supporting the text block.

Accepts one of the following:

type BetaCitationCharLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

FileID string

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

FileID string

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

FileID string

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationsWebSearchResultLocation struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocation struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Text string

Type Text

IsError bool

ToolUseID string

Type MCPToolResult

type BetaContainerUploadBlock struct{…}

Response model for a file uploaded to the container.

FileID string

Type ContainerUpload

type BetaCompactionBlock struct{…}

A compaction block returned when autocompact is triggered.

Content string

Summary of compacted content, or null if compaction failed

Type Compaction

ContextManagement BetaContextManagementResponse

Context management response.

Information about context management strategies applied during the request.

AppliedEdits []BetaContextManagementResponseAppliedEditUnion

List of context management edits that were applied.

Accepts one of the following:

type BetaClearToolUses20250919EditResponse struct{…}

ClearedInputTokens int64

Number of input tokens cleared by this edit.

ClearedToolUses int64

Number of tool uses that were cleared.

Type ClearToolUses20250919

The type of context management edit applied.

type BetaClearThinking20251015EditResponse struct{…}

ClearedInputTokens int64

Number of input tokens cleared by this edit.

ClearedThinkingTurns int64

Number of thinking turns that were cleared.

Type ClearThinking20251015

The type of context management edit applied.

Model Model

The model that will complete your prompt.

See models for additional details and options.

Accepts one of the following:

type Model string

The model that will complete your prompt.

See models for additional details and options.

Accepts one of the following:

const ModelClaudeOpus4_6 Model = "claude-opus-4-6"

Most intelligent model for building agents and coding

const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"

Frontier intelligence at scale — built for coding, agents, and enterprise workflows

const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"

Premium model combining maximum intelligence with practical performance

const ModelClaudeOpus4_5 Model = "claude-opus-4-5"

Premium model combining maximum intelligence with practical performance

const ModelClaude3_7SonnetLatest Model = "claude-3-7-sonnet-latest"

High-performance model with early extended thinking

const ModelClaude3_7Sonnet20250219 Model = "claude-3-7-sonnet-20250219"

High-performance model with early extended thinking

const ModelClaude3_5HaikuLatest Model = "claude-3-5-haiku-latest"

Fastest and most compact model for near-instant responsiveness

const ModelClaude3_5Haiku20241022 Model = "claude-3-5-haiku-20241022"

Our fastest model

const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"

Hybrid model, capable of near-instant responses and extended thinking

const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"

Hybrid model, capable of near-instant responses and extended thinking

const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"

High-performance model with extended thinking

const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"

High-performance model with extended thinking

const ModelClaude4Sonnet20250514 Model = "claude-4-sonnet-20250514"

High-performance model with extended thinking

const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"

Our best model for real-world agents and coding

const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"

Our best model for real-world agents and coding

const ModelClaudeOpus4_0 Model = "claude-opus-4-0"

Our most capable model

const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"

Our most capable model

const ModelClaude4Opus20250514 Model = "claude-4-opus-20250514"

Our most capable model

const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"

Our most capable model

const ModelClaude3OpusLatest Model = "claude-3-opus-latest"

Excels at writing and complex tasks

const ModelClaude_3_Opus_20240229 Model = "claude-3-opus-20240229"

Excels at writing and complex tasks

const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"

Our previous most fast and cost-effective

string

Role Assistant

Conversational role of the generated message.

This will always be "assistant".

StopReason BetaStopReason

The reason that we stopped.

This may be one the following values:

"end_turn": the model reached a natural stopping point
"max_tokens": we exceeded the requested max_tokens or the model's maximum
"stop_sequence": one of your provided custom stop_sequences was generated
"tool_use": the model invoked one or more tools
"pause_turn": we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
"refusal": when streaming classifiers intervene to handle potential policy violations

In non-streaming mode this value is always non-null. In streaming mode, it is null in the message_start event and non-null otherwise.

Accepts one of the following:

const BetaStopReasonEndTurn BetaStopReason = "end_turn"

const BetaStopReasonMaxTokens BetaStopReason = "max_tokens"

const BetaStopReasonStopSequence BetaStopReason = "stop_sequence"

const BetaStopReasonToolUse BetaStopReason = "tool_use"

const BetaStopReasonPauseTurn BetaStopReason = "pause_turn"

const BetaStopReasonCompaction BetaStopReason = "compaction"

const BetaStopReasonRefusal BetaStopReason = "refusal"

const BetaStopReasonModelContextWindowExceeded BetaStopReason = "model_context_window_exceeded"

StopSequence string

Which custom stop sequence was generated, if any.

This value will be a non-null string if one of your custom stop sequences was generated.

Type Message

Object type.

For Messages, this is always "message".

Usage BetaUsage

Billing and rate-limit usage.

Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

For example, output_tokens will be non-zero, even for an empty string response from Claude.

Total input tokens in a request is the summation of input_tokens, cache_creation_input_tokens, and cache_read_input_tokens.

CacheCreation BetaCacheCreation

Breakdown of cached tokens by TTL

Ephemeral1hInputTokens int64

The number of input tokens used to create the 1 hour cache entry.

Ephemeral5mInputTokens int64

The number of input tokens used to create the 5 minute cache entry.

CacheCreationInputTokens int64

The number of input tokens used to create the cache entry.

CacheReadInputTokens int64

The number of input tokens read from the cache.

InferenceGeo string

The geographic region where inference was performed for this request.

InputTokens int64

The number of input tokens which were used.

Iterations BetaIterationsUsage

Per-iteration token usage breakdown.

Each entry represents one sampling iteration, with its own input/output token counts and cache statistics. This allows you to:

Determine which iterations exceeded long context thresholds (>=200k tokens)
Calculate the true context window size from the last iteration
Understand token accumulation across server-side tool use loops

Accepts one of the following:

type BetaMessageIterationUsage struct{…}

Token usage for a sampling iteration.

CacheCreation BetaCacheCreation

Breakdown of cached tokens by TTL

Ephemeral1hInputTokens int64

The number of input tokens used to create the 1 hour cache entry.

Ephemeral5mInputTokens int64

The number of input tokens used to create the 5 minute cache entry.

CacheCreationInputTokens int64

The number of input tokens used to create the cache entry.

CacheReadInputTokens int64

The number of input tokens read from the cache.

InputTokens int64

The number of input tokens which were used.

OutputTokens int64

The number of output tokens which were used.

Type Message

Usage for a sampling iteration

type BetaCompactionIterationUsage struct{…}

Token usage for a compaction iteration.

CacheCreation BetaCacheCreation

Breakdown of cached tokens by TTL

Ephemeral1hInputTokens int64

The number of input tokens used to create the 1 hour cache entry.

Ephemeral5mInputTokens int64

The number of input tokens used to create the 5 minute cache entry.

CacheCreationInputTokens int64

The number of input tokens used to create the cache entry.

CacheReadInputTokens int64

The number of input tokens read from the cache.

InputTokens int64

The number of input tokens which were used.

OutputTokens int64

The number of output tokens which were used.

Type Compaction

Usage for a compaction iteration

OutputTokens int64

The number of output tokens which were used.

ServerToolUse BetaServerToolUsage

The number of server tool requests.

WebFetchRequests int64

The number of web fetch tool requests.

WebSearchRequests int64

The number of web search tool requests.

ServiceTier BetaUsageServiceTier

If the request used the priority, standard, or batch tier.

Accepts one of the following:

const BetaUsageServiceTierStandard BetaUsageServiceTier = "standard"

const BetaUsageServiceTierPriority BetaUsageServiceTier = "priority"

const BetaUsageServiceTierBatch BetaUsageServiceTier = "batch"

Speed BetaUsageSpeed

The inference speed mode used for this request.

Accepts one of the following:

const BetaUsageSpeedStandard BetaUsageSpeed = "standard"

const BetaUsageSpeedFast BetaUsageSpeed = "fast"

Type MessageStart

type BetaRawMessageDeltaEvent struct{…}

ContextManagement BetaContextManagementResponse

Information about context management strategies applied during the request

AppliedEdits []BetaContextManagementResponseAppliedEditUnion

List of context management edits that were applied.

Accepts one of the following:

type BetaClearToolUses20250919EditResponse struct{…}

ClearedInputTokens int64

Number of input tokens cleared by this edit.

ClearedToolUses int64

Number of tool uses that were cleared.

Type ClearToolUses20250919

The type of context management edit applied.

type BetaClearThinking20251015EditResponse struct{…}

ClearedInputTokens int64

Number of input tokens cleared by this edit.

ClearedThinkingTurns int64

Number of thinking turns that were cleared.

Type ClearThinking20251015

The type of context management edit applied.

Delta BetaRawMessageDeltaEventDelta

Container BetaContainer

Information about the container used in the request (for the code execution tool)

ID string

Identifier for the container used in this request

ExpiresAt Time

The time at which the container will expire.

Skills []BetaSkill

Skills loaded in the container

SkillID string

Skill ID

Type BetaSkillType

Type of skill - either 'anthropic' (built-in) or 'custom' (user-defined)

Accepts one of the following:

const BetaSkillTypeAnthropic BetaSkillType = "anthropic"

const BetaSkillTypeCustom BetaSkillType = "custom"

Version string

Skill version or 'latest' for most recent version

StopReason BetaStopReason

Accepts one of the following:

const BetaStopReasonEndTurn BetaStopReason = "end_turn"

const BetaStopReasonMaxTokens BetaStopReason = "max_tokens"

const BetaStopReasonStopSequence BetaStopReason = "stop_sequence"

const BetaStopReasonToolUse BetaStopReason = "tool_use"

const BetaStopReasonPauseTurn BetaStopReason = "pause_turn"

const BetaStopReasonCompaction BetaStopReason = "compaction"

const BetaStopReasonRefusal BetaStopReason = "refusal"

const BetaStopReasonModelContextWindowExceeded BetaStopReason = "model_context_window_exceeded"

StopSequence string

Type MessageDelta

Usage BetaMessageDeltaUsage

Billing and rate-limit usage.

Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

For example, output_tokens will be non-zero, even for an empty string response from Claude.

Total input tokens in a request is the summation of input_tokens, cache_creation_input_tokens, and cache_read_input_tokens.

CacheCreationInputTokens int64

The cumulative number of input tokens used to create the cache entry.

CacheReadInputTokens int64

The cumulative number of input tokens read from the cache.

InputTokens int64

The cumulative number of input tokens which were used.

Iterations BetaIterationsUsage

Per-iteration token usage breakdown.

Each entry represents one sampling iteration, with its own input/output token counts and cache statistics. This allows you to:

Determine which iterations exceeded long context thresholds (>=200k tokens)
Calculate the true context window size from the last iteration
Understand token accumulation across server-side tool use loops

Accepts one of the following:

type BetaMessageIterationUsage struct{…}

Token usage for a sampling iteration.

CacheCreation BetaCacheCreation

Breakdown of cached tokens by TTL

Ephemeral1hInputTokens int64

The number of input tokens used to create the 1 hour cache entry.

Ephemeral5mInputTokens int64

The number of input tokens used to create the 5 minute cache entry.

CacheCreationInputTokens int64

The number of input tokens used to create the cache entry.

CacheReadInputTokens int64

The number of input tokens read from the cache.

InputTokens int64

The number of input tokens which were used.

OutputTokens int64

The number of output tokens which were used.

Type Message

Usage for a sampling iteration

type BetaCompactionIterationUsage struct{…}

Token usage for a compaction iteration.

CacheCreation BetaCacheCreation

Breakdown of cached tokens by TTL

Ephemeral1hInputTokens int64

The number of input tokens used to create the 1 hour cache entry.

Ephemeral5mInputTokens int64

The number of input tokens used to create the 5 minute cache entry.

CacheCreationInputTokens int64

The number of input tokens used to create the cache entry.

CacheReadInputTokens int64

The number of input tokens read from the cache.

InputTokens int64

The number of input tokens which were used.

OutputTokens int64

The number of output tokens which were used.

Type Compaction

Usage for a compaction iteration

OutputTokens int64

The cumulative number of output tokens which were used.

ServerToolUse BetaServerToolUsage

The number of server tool requests.

WebFetchRequests int64

The number of web fetch tool requests.

WebSearchRequests int64

The number of web search tool requests.

type BetaRawMessageStopEvent struct{…}

Type MessageStop

type BetaRawContentBlockStartEvent struct{…}

ContentBlock BetaRawContentBlockStartEventContentBlockUnion

Response model for a file uploaded to the container.

Accepts one of the following:

type BetaTextBlock struct{…}

Citations []BetaTextCitationUnion

Citations supporting the text block.

Accepts one of the following:

type BetaCitationCharLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

FileID string

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

FileID string

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

FileID string

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationsWebSearchResultLocation struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocation struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Text string

Type Text

type BetaThinkingBlock struct{…}

Signature string

Thinking string

Type Thinking

type BetaRedactedThinkingBlock struct{…}

Data string

Type RedactedThinking

type BetaToolUseBlock struct{…}

ID string

Input map[string, any]

Name string

Type ToolUse

Caller BetaToolUseBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaServerToolUseBlock struct{…}

ID string

Input map[string, any]

Name BetaServerToolUseBlockName

Accepts one of the following:

const BetaServerToolUseBlockNameWebSearch BetaServerToolUseBlockName = "web_search"

const BetaServerToolUseBlockNameWebFetch BetaServerToolUseBlockName = "web_fetch"

const BetaServerToolUseBlockNameCodeExecution BetaServerToolUseBlockName = "code_execution"

const BetaServerToolUseBlockNameBashCodeExecution BetaServerToolUseBlockName = "bash_code_execution"

const BetaServerToolUseBlockNameTextEditorCodeExecution BetaServerToolUseBlockName = "text_editor_code_execution"

const BetaServerToolUseBlockNameToolSearchToolRegex BetaServerToolUseBlockName = "tool_search_tool_regex"

const BetaServerToolUseBlockNameToolSearchToolBm25 BetaServerToolUseBlockName = "tool_search_tool_bm25"

Type ServerToolUse

Caller BetaServerToolUseBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaWebSearchToolResultBlock struct{…}

Content BetaWebSearchToolResultBlockContentUnion

Accepts one of the following:

type BetaWebSearchToolResultError struct{…}

ErrorCode BetaWebSearchToolResultErrorCode

Accepts one of the following:

const BetaWebSearchToolResultErrorCodeInvalidToolInput BetaWebSearchToolResultErrorCode = "invalid_tool_input"

const BetaWebSearchToolResultErrorCodeUnavailable BetaWebSearchToolResultErrorCode = "unavailable"

const BetaWebSearchToolResultErrorCodeMaxUsesExceeded BetaWebSearchToolResultErrorCode = "max_uses_exceeded"

const BetaWebSearchToolResultErrorCodeTooManyRequests BetaWebSearchToolResultErrorCode = "too_many_requests"

const BetaWebSearchToolResultErrorCodeQueryTooLong BetaWebSearchToolResultErrorCode = "query_too_long"

const BetaWebSearchToolResultErrorCodeRequestTooLarge BetaWebSearchToolResultErrorCode = "request_too_large"

Type WebSearchToolResultError

type BetaWebSearchToolResultBlockContentArray []BetaWebSearchResultBlock

EncryptedContent string

PageAge string

Title string

Type WebSearchResult

URL string

ToolUseID string

Type WebSearchToolResult

Caller BetaWebSearchToolResultBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaWebFetchToolResultBlock struct{…}

Content BetaWebFetchToolResultBlockContentUnion

Accepts one of the following:

type BetaWebFetchToolResultErrorBlock struct{…}

ErrorCode BetaWebFetchToolResultErrorCode

Accepts one of the following:

const BetaWebFetchToolResultErrorCodeInvalidToolInput BetaWebFetchToolResultErrorCode = "invalid_tool_input"

const BetaWebFetchToolResultErrorCodeURLTooLong BetaWebFetchToolResultErrorCode = "url_too_long"

const BetaWebFetchToolResultErrorCodeURLNotAllowed BetaWebFetchToolResultErrorCode = "url_not_allowed"

const BetaWebFetchToolResultErrorCodeURLNotAccessible BetaWebFetchToolResultErrorCode = "url_not_accessible"

const BetaWebFetchToolResultErrorCodeUnsupportedContentType BetaWebFetchToolResultErrorCode = "unsupported_content_type"

const BetaWebFetchToolResultErrorCodeTooManyRequests BetaWebFetchToolResultErrorCode = "too_many_requests"

const BetaWebFetchToolResultErrorCodeMaxUsesExceeded BetaWebFetchToolResultErrorCode = "max_uses_exceeded"

const BetaWebFetchToolResultErrorCodeUnavailable BetaWebFetchToolResultErrorCode = "unavailable"

Type WebFetchToolResultError

type BetaWebFetchBlock struct{…}

Content BetaDocumentBlock

Citations BetaCitationConfig

Citation configuration for the document

Enabled bool

Source BetaDocumentBlockSourceUnion

Accepts one of the following:

type BetaBase64PDFSource struct{…}

Data string

MediaType ApplicationPDF

Type Base64

type BetaPlainTextSource struct{…}

Data string

MediaType TextPlain

Type Text

Title string

The title of the document

Type Document

RetrievedAt string

ISO 8601 timestamp when the content was retrieved

Type WebFetchResult

URL string

Fetched content URL

ToolUseID string

Type WebFetchToolResult

Caller BetaWebFetchToolResultBlockCallerUnionoptional

Tool invocation directly from the model.

Accepts one of the following:

type BetaDirectCaller struct{…}

Tool invocation directly from the model.

Type Direct

type BetaServerToolCaller struct{…}

Tool invocation generated by a server-side tool.

ToolID string

Type CodeExecution20250825

type BetaServerToolCaller20260120 struct{…}

ToolID string

Type CodeExecution20260120

type BetaCodeExecutionToolResultBlock struct{…}

Content BetaCodeExecutionToolResultBlockContentUnion

Code execution result with encrypted stdout for PFC + web_search results.

Accepts one of the following:

type BetaCodeExecutionToolResultError struct{…}

ErrorCode BetaCodeExecutionToolResultErrorCode

Accepts one of the following:

const BetaCodeExecutionToolResultErrorCodeInvalidToolInput BetaCodeExecutionToolResultErrorCode = "invalid_tool_input"

const BetaCodeExecutionToolResultErrorCodeUnavailable BetaCodeExecutionToolResultErrorCode = "unavailable"

const BetaCodeExecutionToolResultErrorCodeTooManyRequests BetaCodeExecutionToolResultErrorCode = "too_many_requests"

const BetaCodeExecutionToolResultErrorCodeExecutionTimeExceeded BetaCodeExecutionToolResultErrorCode = "execution_time_exceeded"

Type CodeExecutionToolResultError

type BetaCodeExecutionResultBlock struct{…}

Content []BetaCodeExecutionOutputBlock

FileID string

Type CodeExecutionOutput

ReturnCode int64

Stderr string

Stdout string

Type CodeExecutionResult

type BetaEncryptedCodeExecutionResultBlock struct{…}

Code execution result with encrypted stdout for PFC + web_search results.

Content []BetaCodeExecutionOutputBlock

FileID string

Type CodeExecutionOutput

EncryptedStdout string

ReturnCode int64

Stderr string

Type EncryptedCodeExecutionResult

ToolUseID string

Type CodeExecutionToolResult

type BetaBashCodeExecutionToolResultBlock struct{…}

Content BetaBashCodeExecutionToolResultBlockContentUnion

Accepts one of the following:

type BetaBashCodeExecutionToolResultError struct{…}

ErrorCode BetaBashCodeExecutionToolResultErrorErrorCode

Accepts one of the following:

const BetaBashCodeExecutionToolResultErrorErrorCodeInvalidToolInput BetaBashCodeExecutionToolResultErrorErrorCode = "invalid_tool_input"

const BetaBashCodeExecutionToolResultErrorErrorCodeUnavailable BetaBashCodeExecutionToolResultErrorErrorCode = "unavailable"

const BetaBashCodeExecutionToolResultErrorErrorCodeTooManyRequests BetaBashCodeExecutionToolResultErrorErrorCode = "too_many_requests"

const BetaBashCodeExecutionToolResultErrorErrorCodeExecutionTimeExceeded BetaBashCodeExecutionToolResultErrorErrorCode = "execution_time_exceeded"

const BetaBashCodeExecutionToolResultErrorErrorCodeOutputFileTooLarge BetaBashCodeExecutionToolResultErrorErrorCode = "output_file_too_large"

Type BashCodeExecutionToolResultError

type BetaBashCodeExecutionResultBlock struct{…}

Content []BetaBashCodeExecutionOutputBlock

FileID string

Type BashCodeExecutionOutput

ReturnCode int64

Stderr string

Stdout string

Type BashCodeExecutionResult

ToolUseID string

Type BashCodeExecutionToolResult

type BetaTextEditorCodeExecutionToolResultBlock struct{…}

Content BetaTextEditorCodeExecutionToolResultBlockContentUnion

Accepts one of the following:

type BetaTextEditorCodeExecutionToolResultError struct{…}

ErrorCode BetaTextEditorCodeExecutionToolResultErrorErrorCode

Accepts one of the following:

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeInvalidToolInput BetaTextEditorCodeExecutionToolResultErrorErrorCode = "invalid_tool_input"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeUnavailable BetaTextEditorCodeExecutionToolResultErrorErrorCode = "unavailable"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeTooManyRequests BetaTextEditorCodeExecutionToolResultErrorErrorCode = "too_many_requests"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeExecutionTimeExceeded BetaTextEditorCodeExecutionToolResultErrorErrorCode = "execution_time_exceeded"

const BetaTextEditorCodeExecutionToolResultErrorErrorCodeFileNotFound BetaTextEditorCodeExecutionToolResultErrorErrorCode = "file_not_found"

ErrorMessage string

Type TextEditorCodeExecutionToolResultError

type BetaTextEditorCodeExecutionViewResultBlock struct{…}

Content string

FileType BetaTextEditorCodeExecutionViewResultBlockFileType

Accepts one of the following:

const BetaTextEditorCodeExecutionViewResultBlockFileTypeText BetaTextEditorCodeExecutionViewResultBlockFileType = "text"

const BetaTextEditorCodeExecutionViewResultBlockFileTypeImage BetaTextEditorCodeExecutionViewResultBlockFileType = "image"

const BetaTextEditorCodeExecutionViewResultBlockFileTypePDF BetaTextEditorCodeExecutionViewResultBlockFileType = "pdf"

NumLines int64

StartLine int64

TotalLines int64

Type TextEditorCodeExecutionViewResult

type BetaTextEditorCodeExecutionCreateResultBlock struct{…}

IsFileUpdate bool

Type TextEditorCodeExecutionCreateResult

type BetaTextEditorCodeExecutionStrReplaceResultBlock struct{…}

Lines []string

NewLines int64

NewStart int64

OldLines int64

OldStart int64

Type TextEditorCodeExecutionStrReplaceResult

ToolUseID string

Type TextEditorCodeExecutionToolResult

type BetaToolSearchToolResultBlock struct{…}

Content BetaToolSearchToolResultBlockContentUnion

Accepts one of the following:

type BetaToolSearchToolResultError struct{…}

ErrorCode BetaToolSearchToolResultErrorErrorCode

Accepts one of the following:

const BetaToolSearchToolResultErrorErrorCodeInvalidToolInput BetaToolSearchToolResultErrorErrorCode = "invalid_tool_input"

const BetaToolSearchToolResultErrorErrorCodeUnavailable BetaToolSearchToolResultErrorErrorCode = "unavailable"

const BetaToolSearchToolResultErrorErrorCodeTooManyRequests BetaToolSearchToolResultErrorErrorCode = "too_many_requests"

const BetaToolSearchToolResultErrorErrorCodeExecutionTimeExceeded BetaToolSearchToolResultErrorErrorCode = "execution_time_exceeded"

ErrorMessage string

Type ToolSearchToolResultError

type BetaToolSearchToolSearchResultBlock struct{…}

ToolReferences []BetaToolReferenceBlock

ToolName string

Type ToolReference

Type ToolSearchToolSearchResult

ToolUseID string

Type ToolSearchToolResult

type BetaMCPToolUseBlock struct{…}

ID string

Input map[string, any]

Name string

The name of the MCP tool

ServerName string

The name of the MCP server

Type MCPToolUse

type BetaMCPToolResultBlock struct{…}

Content BetaMCPToolResultBlockContentUnion

Accepts one of the following:

string

type BetaMCPToolResultBlockContentBetaMCPToolResultBlockContent []BetaTextBlock

Citations []BetaTextCitationUnion

Citations supporting the text block.

Accepts one of the following:

type BetaCitationCharLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

FileID string

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

FileID string

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

FileID string

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationsWebSearchResultLocation struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocation struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Text string

Type Text

IsError bool

ToolUseID string

Type MCPToolResult

type BetaContainerUploadBlock struct{…}

Response model for a file uploaded to the container.

FileID string

Type ContainerUpload

type BetaCompactionBlock struct{…}

A compaction block returned when autocompact is triggered.

Content string

Summary of compacted content, or null if compaction failed

Type Compaction

Index int64

Type ContentBlockStart

type BetaRawContentBlockDeltaEvent struct{…}

Delta BetaRawContentBlockDeltaUnion

Accepts one of the following:

type BetaTextDelta struct{…}

Text string

Type TextDelta

type BetaInputJSONDelta struct{…}

PartialJSON string

Type InputJSONDelta

type BetaCitationsDelta struct{…}

Citation BetaCitationsDeltaCitationUnion

Accepts one of the following:

type BetaCitationCharLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndCharIndex int64

FileID string

StartCharIndex int64

Type CharLocation

type BetaCitationPageLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndPageNumber int64

FileID string

StartPageNumber int64

Type PageLocation

type BetaCitationContentBlockLocation struct{…}

CitedText string

DocumentIndex int64

DocumentTitle string

EndBlockIndex int64

FileID string

StartBlockIndex int64

Type ContentBlockLocation

type BetaCitationsWebSearchResultLocation struct{…}

CitedText string

EncryptedIndex string

Title string

Type WebSearchResultLocation

URL string

type BetaCitationSearchResultLocation struct{…}

CitedText string

EndBlockIndex int64

SearchResultIndex int64

Source string

StartBlockIndex int64

Title string

Type SearchResultLocation

Type CitationsDelta

type BetaThinkingDelta struct{…}

Thinking string

Type ThinkingDelta

type BetaSignatureDelta struct{…}

Signature string

Type SignatureDelta

type BetaCompactionContentBlockDelta struct{…}

Content string

Type CompactionDelta

Index int64

Type ContentBlockDelta

type BetaRawContentBlockStopEvent struct{…}

Index int64

Type ContentBlockStop

Create a Message

package main

import (
  "context"
  "fmt"

  "github.com/anthropics/anthropic-sdk-go"
  "github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
  client := anthropic.NewClient(
    option.WithAPIKey("my-anthropic-api-key"),
  )
  betaMessage, err := client.Beta.Messages.New(context.TODO(), anthropic.BetaMessageNewParams{
    MaxTokens: 1024,
    Messages: []anthropic.BetaMessageParam{anthropic.BetaMessageParam{
      Content: []anthropic.BetaContentBlockParamUnion{anthropic.BetaContentBlockParamUnion{
        OfText: &anthropic.BetaTextBlockParam{
          Text: "x",
        },
      }},
      Role: anthropic.BetaMessageParamRoleUser,
    }},
    Model: anthropic.ModelClaudeOpus4_6,
  })
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", betaMessage.ID)
}

Response 200

{
  "id": "msg_013Zva2CMHLNnXjNJJKqJ2EF",
  "container": {
    "id": "id",
    "expires_at": "2019-12-27T18:11:19.117Z",
    "skills": [
      {
        "skill_id": "x",
        "type": "anthropic",
        "version": "x"
      }
    ]
  },
  "content": [
    {
      "citations": [
        {
          "cited_text": "cited_text",
          "document_index": 0,
          "document_title": "document_title",
          "end_char_index": 0,
          "file_id": "file_id",
          "start_char_index": 0,
          "type": "char_location"
        }
      ],
      "text": "Hi! My name is Claude.",
      "type": "text"
    }
  ],
  "context_management": {
    "applied_edits": [
      {
        "cleared_input_tokens": 0,
        "cleared_tool_uses": 0,
        "type": "clear_tool_uses_20250919"
      }
    ]
  },
  "model": "claude-opus-4-6",
  "role": "assistant",
  "stop_reason": "end_turn",
  "stop_sequence": null,
  "type": "message",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_creation_input_tokens": 2051,
    "cache_read_input_tokens": 2051,
    "inference_geo": "inference_geo",
    "input_tokens": 2095,
    "iterations": [
      {
        "cache_creation": {
          "ephemeral_1h_input_tokens": 0,
          "ephemeral_5m_input_tokens": 0
        },
        "cache_creation_input_tokens": 0,
        "cache_read_input_tokens": 0,
        "input_tokens": 0,
        "output_tokens": 0,
        "type": "message"
      }
    ],
    "output_tokens": 503,
    "server_tool_use": {
      "web_fetch_requests": 2,
      "web_search_requests": 0
    },
    "service_tier": "standard",
    "speed": "standard"
  }
}

Returns Examples

Response 200

{
  "id": "msg_013Zva2CMHLNnXjNJJKqJ2EF",
  "container": {
    "id": "id",
    "expires_at": "2019-12-27T18:11:19.117Z",
    "skills": [
      {
        "skill_id": "x",
        "type": "anthropic",
        "version": "x"
      }
    ]
  },
  "content": [
    {
      "citations": [
        {
          "cited_text": "cited_text",
          "document_index": 0,
          "document_title": "document_title",
          "end_char_index": 0,
          "file_id": "file_id",
          "start_char_index": 0,
          "type": "char_location"
        }
      ],
      "text": "Hi! My name is Claude.",
      "type": "text"
    }
  ],
  "context_management": {
    "applied_edits": [
      {
        "cleared_input_tokens": 0,
        "cleared_tool_uses": 0,
        "type": "clear_tool_uses_20250919"
      }
    ]
  },
  "model": "claude-opus-4-6",
  "role": "assistant",
  "stop_reason": "end_turn",
  "stop_sequence": null,
  "type": "message",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_creation_input_tokens": 2051,
    "cache_read_input_tokens": 2051,
    "inference_geo": "inference_geo",
    "input_tokens": 2095,
    "iterations": [
      {
        "cache_creation": {
          "ephemeral_1h_input_tokens": 0,
          "ephemeral_5m_input_tokens": 0
        },
        "cache_creation_input_tokens": 0,
        "cache_read_input_tokens": 0,
        "input_tokens": 0,
        "output_tokens": 0,
        "type": "message"
      }
    ],
    "output_tokens": 503,
    "server_tool_use": {
      "web_fetch_requests": 2,
      "web_search_requests": 0
    },
    "service_tier": "standard",
    "speed": "standard"
  }
}