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Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
Base64PDFSource = object { data, media_type, type }
media_type: "application/pdf"
type: "base64"
CacheControlEphemeral = object { type, ttl }
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CacheCreation = object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }
ephemeral_1h_input_tokens: number
The number of input tokens used to create the 1 hour cache entry.
ephemeral_5m_input_tokens: number
The number of input tokens used to create the 5 minute cache entry.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsConfigParam = object { enabled }
CitationsDelta = object { citation, type }
citation: CitationCharLocation { cited_text, document_index, document_title, 4 more } or CitationPageLocation { cited_text, document_index, document_title, 4 more } or CitationContentBlockLocation { cited_text, document_index, document_title, 4 more } or 2 more
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "citations_delta"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
ContentBlock = TextBlock { citations, text, type } or ThinkingBlock { signature, thinking, type } or RedactedThinkingBlock { data, type } or 3 more
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
ContentBlockParam = TextBlockParam { text, type, cache_control, citations } or ImageBlockParam { source, type, cache_control } or DocumentBlockParam { source, type, cache_control, 3 more } or 7 more
Regular text content.
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
DocumentBlockParam = object { source, type, cache_control, 3 more }
source: Base64PDFSource { data, media_type, type } or PlainTextSource { data, media_type, type } or ContentBlockSource { content, type } or URLPDFSource { type, url }
Base64PDFSource = object { data, media_type, type }
media_type: "application/pdf"
type: "base64"
PlainTextSource = object { data, media_type, type }
media_type: "text/plain"
type: "text"
ContentBlockSource = object { content, type }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
type: "content"
URLPDFSource = object { type, url }
type: "url"
type: "document"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
SearchResultBlockParam = object { content, source, title, 3 more }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "search_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ThinkingBlockParam = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlockParam = object { data, type }
type: "redacted_thinking"
ToolUseBlockParam = object { id, input, name, 2 more }
type: "tool_use"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolResultBlockParam = object { tool_use_id, type, cache_control, 2 more }
type: "tool_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
content: optional string or array of TextBlockParam { text, type, cache_control, citations } or ImageBlockParam { source, type, cache_control } or SearchResultBlockParam { content, source, title, 3 more } or DocumentBlockParam { source, type, cache_control, 3 more }
UnionMember1 = array of TextBlockParam { text, type, cache_control, citations } or ImageBlockParam { source, type, cache_control } or SearchResultBlockParam { content, source, title, 3 more } or DocumentBlockParam { source, type, cache_control, 3 more }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
SearchResultBlockParam = object { content, source, title, 3 more }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "search_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
DocumentBlockParam = object { source, type, cache_control, 3 more }
source: Base64PDFSource { data, media_type, type } or PlainTextSource { data, media_type, type } or ContentBlockSource { content, type } or URLPDFSource { type, url }
Base64PDFSource = object { data, media_type, type }
media_type: "application/pdf"
type: "base64"
PlainTextSource = object { data, media_type, type }
media_type: "text/plain"
type: "text"
ContentBlockSource = object { content, type }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
type: "content"
URLPDFSource = object { type, url }
type: "url"
type: "document"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ServerToolUseBlockParam = object { id, input, name, 2 more }
name: "web_search"
type: "server_tool_use"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
WebSearchToolResultBlockParam = object { content, tool_use_id, type, cache_control }
WebSearchToolResultBlockItem = array of WebSearchResultBlockParam { encrypted_content, title, type, 2 more }
type: "web_search_result"
WebSearchToolRequestError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_tool_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ContentBlockSource = object { content, type }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
type: "content"
ContentBlockSourceContent = TextBlockParam { text, type, cache_control, citations } or ImageBlockParam { source, type, cache_control }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
DocumentBlockParam = object { source, type, cache_control, 3 more }
source: Base64PDFSource { data, media_type, type } or PlainTextSource { data, media_type, type } or ContentBlockSource { content, type } or URLPDFSource { type, url }
Base64PDFSource = object { data, media_type, type }
media_type: "application/pdf"
type: "base64"
PlainTextSource = object { data, media_type, type }
media_type: "text/plain"
type: "text"
ContentBlockSource = object { content, type }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
type: "content"
URLPDFSource = object { type, url }
type: "url"
type: "document"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
InputJSONDelta = object { partial_json, type }
type: "input_json_delta"
Message = object { id, content, model, 5 more }
id: string
Unique object identifier.
The format and length of IDs may change over time.
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)"}]
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
The model that will complete your prompt.
See models for additional details and options.
UnionMember0 = "claude-opus-4-5-20251101" or "claude-opus-4-5" or "claude-3-7-sonnet-latest" or 17 more
The model that will complete your prompt.
See models for additional details and options.
"claude-opus-4-5-20251101"
Premium model combining maximum intelligence with practical performance
"claude-opus-4-5"
Premium model combining maximum intelligence with practical performance
"claude-3-7-sonnet-latest"
High-performance model with early extended thinking
"claude-3-7-sonnet-20250219"
High-performance model with early extended thinking
"claude-3-5-haiku-latest"
Fastest and most compact model for near-instant responsiveness
"claude-3-5-haiku-20241022"
Our fastest model
"claude-haiku-4-5"
Hybrid model, capable of near-instant responses and extended thinking
"claude-haiku-4-5-20251001"
Hybrid model, capable of near-instant responses and extended thinking
"claude-sonnet-4-20250514"
High-performance model with extended thinking
"claude-sonnet-4-0"
High-performance model with extended thinking
"claude-4-sonnet-20250514"
High-performance model with extended thinking
"claude-sonnet-4-5"
Our best model for real-world agents and coding
"claude-sonnet-4-5-20250929"
Our best model for real-world agents and coding
"claude-opus-4-0"
Our most capable model
"claude-opus-4-20250514"
Our most capable model
"claude-4-opus-20250514"
Our most capable model
"claude-opus-4-1-20250805"
Our most capable model
"claude-3-opus-latest"
Excels at writing and complex tasks
"claude-3-opus-20240229"
Excels at writing and complex tasks
"claude-3-haiku-20240307"
Our previous most fast and cost-effective
role: "assistant"
Conversational role of the generated message.
This will always be "assistant".
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 requestedmax_tokensor the model's maximum"stop_sequence": one of your provided customstop_sequenceswas 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.
stop_sequence: 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".
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.
Breakdown of cached tokens by TTL
ephemeral_1h_input_tokens: number
The number of input tokens used to create the 1 hour cache entry.
ephemeral_5m_input_tokens: number
The number of input tokens used to create the 5 minute cache entry.
cache_creation_input_tokens: number
The number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The number of input tokens read from the cache.
input_tokens: number
The number of input tokens which were used.
output_tokens: number
The number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
service_tier: "standard" or "priority" or "batch"
If the request used the priority, standard, or batch tier.
MessageCountTokensTool = Tool { input_schema, name, cache_control, 2 more } or ToolBash20250124 { name, type, cache_control } or ToolTextEditor20250124 { name, type, cache_control } or 3 more
Tool = object { input_schema, name, cache_control, 2 more }
input_schema: object { type, properties, required }
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"
name: string
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
description: optional string
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.
type: optional "custom"
ToolBash20250124 = object { name, type, cache_control }
name: "bash"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "bash_20250124"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolTextEditor20250124 = object { name, type, cache_control }
name: "str_replace_editor"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "text_editor_20250124"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolTextEditor20250429 = object { name, type, cache_control }
name: "str_replace_based_edit_tool"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "text_editor_20250429"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolTextEditor20250728 = object { name, type, cache_control, max_characters }
name: "str_replace_based_edit_tool"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "text_editor_20250728"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
max_characters: optional number
Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.
WebSearchTool20250305 = object { name, type, allowed_domains, 4 more }
name: "web_search"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "web_search_20250305"
allowed_domains: optional array of string
If provided, only these domains will be included in results. Cannot be used alongside blocked_domains.
blocked_domains: optional array of string
If provided, these domains will never appear in results. Cannot be used alongside allowed_domains.
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
max_uses: optional number
Maximum number of times the tool can be used in the API request.
user_location: optional object { type, city, country, 2 more }
Parameters for the user's location. Used to provide more relevant search results.
type: "approximate"
city: optional string
The city of the user.
country: optional string
The two letter ISO country code of the user.
region: optional string
The region of the user.
timezone: optional string
The IANA timezone of the user.
MessageDeltaUsage = object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }
cache_creation_input_tokens: number
The cumulative number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The cumulative number of input tokens read from the cache.
input_tokens: number
The cumulative number of input tokens which were used.
output_tokens: number
The cumulative number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
MessageParam = object { content, role }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
DocumentBlockParam = object { source, type, cache_control, 3 more }
source: Base64PDFSource { data, media_type, type } or PlainTextSource { data, media_type, type } or ContentBlockSource { content, type } or URLPDFSource { type, url }
Base64PDFSource = object { data, media_type, type }
media_type: "application/pdf"
type: "base64"
PlainTextSource = object { data, media_type, type }
media_type: "text/plain"
type: "text"
ContentBlockSource = object { content, type }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
type: "content"
URLPDFSource = object { type, url }
type: "url"
type: "document"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
SearchResultBlockParam = object { content, source, title, 3 more }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "search_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ThinkingBlockParam = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlockParam = object { data, type }
type: "redacted_thinking"
ToolUseBlockParam = object { id, input, name, 2 more }
type: "tool_use"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolResultBlockParam = object { tool_use_id, type, cache_control, 2 more }
type: "tool_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
content: optional string or array of TextBlockParam { text, type, cache_control, citations } or ImageBlockParam { source, type, cache_control } or SearchResultBlockParam { content, source, title, 3 more } or DocumentBlockParam { source, type, cache_control, 3 more }
UnionMember1 = array of TextBlockParam { text, type, cache_control, citations } or ImageBlockParam { source, type, cache_control } or SearchResultBlockParam { content, source, title, 3 more } or DocumentBlockParam { source, type, cache_control, 3 more }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
SearchResultBlockParam = object { content, source, title, 3 more }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "search_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
DocumentBlockParam = object { source, type, cache_control, 3 more }
source: Base64PDFSource { data, media_type, type } or PlainTextSource { data, media_type, type } or ContentBlockSource { content, type } or URLPDFSource { type, url }
Base64PDFSource = object { data, media_type, type }
media_type: "application/pdf"
type: "base64"
PlainTextSource = object { data, media_type, type }
media_type: "text/plain"
type: "text"
ContentBlockSource = object { content, type }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
type: "content"
URLPDFSource = object { type, url }
type: "url"
type: "document"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ServerToolUseBlockParam = object { id, input, name, 2 more }
name: "web_search"
type: "server_tool_use"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
WebSearchToolResultBlockParam = object { content, tool_use_id, type, cache_control }
WebSearchToolResultBlockItem = array of WebSearchResultBlockParam { encrypted_content, title, type, 2 more }
type: "web_search_result"
WebSearchToolRequestError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_tool_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
role: "user" or "assistant"
MessageTokensCount = object { input_tokens }
input_tokens: number
The total number of tokens across the provided list of messages, system prompt, and tools.
Metadata = object { user_id }
user_id: optional string
An external identifier for the user who is associated with the request.
This should be a uuid, hash value, or other opaque identifier. Anthropic may use this id to help detect abuse. Do not include any identifying information such as name, email address, or phone number.
Model = "claude-opus-4-5-20251101" or "claude-opus-4-5" or "claude-3-7-sonnet-latest" or 17 more or string
The model that will complete your prompt.
See models for additional details and options.
UnionMember0 = "claude-opus-4-5-20251101" or "claude-opus-4-5" or "claude-3-7-sonnet-latest" or 17 more
The model that will complete your prompt.
See models for additional details and options.
"claude-opus-4-5-20251101"
Premium model combining maximum intelligence with practical performance
"claude-opus-4-5"
Premium model combining maximum intelligence with practical performance
"claude-3-7-sonnet-latest"
High-performance model with early extended thinking
"claude-3-7-sonnet-20250219"
High-performance model with early extended thinking
"claude-3-5-haiku-latest"
Fastest and most compact model for near-instant responsiveness
"claude-3-5-haiku-20241022"
Our fastest model
"claude-haiku-4-5"
Hybrid model, capable of near-instant responses and extended thinking
"claude-haiku-4-5-20251001"
Hybrid model, capable of near-instant responses and extended thinking
"claude-sonnet-4-20250514"
High-performance model with extended thinking
"claude-sonnet-4-0"
High-performance model with extended thinking
"claude-4-sonnet-20250514"
High-performance model with extended thinking
"claude-sonnet-4-5"
Our best model for real-world agents and coding
"claude-sonnet-4-5-20250929"
Our best model for real-world agents and coding
"claude-opus-4-0"
Our most capable model
"claude-opus-4-20250514"
Our most capable model
"claude-4-opus-20250514"
Our most capable model
"claude-opus-4-1-20250805"
Our most capable model
"claude-3-opus-latest"
Excels at writing and complex tasks
"claude-3-opus-20240229"
Excels at writing and complex tasks
"claude-3-haiku-20240307"
Our previous most fast and cost-effective
PlainTextSource = object { data, media_type, type }
media_type: "text/plain"
type: "text"
RawContentBlockDelta = TextDelta { text, type } or InputJSONDelta { partial_json, type } or CitationsDelta { citation, type } or 2 more
TextDelta = object { text, type }
type: "text_delta"
InputJSONDelta = object { partial_json, type }
type: "input_json_delta"
CitationsDelta = object { citation, type }
citation: CitationCharLocation { cited_text, document_index, document_title, 4 more } or CitationPageLocation { cited_text, document_index, document_title, 4 more } or CitationContentBlockLocation { cited_text, document_index, document_title, 4 more } or 2 more
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "citations_delta"
ThinkingDelta = object { thinking, type }
type: "thinking_delta"
SignatureDelta = object { signature, type }
type: "signature_delta"
RawContentBlockDeltaEvent = object { delta, index, type }
TextDelta = object { text, type }
type: "text_delta"
InputJSONDelta = object { partial_json, type }
type: "input_json_delta"
CitationsDelta = object { citation, type }
citation: CitationCharLocation { cited_text, document_index, document_title, 4 more } or CitationPageLocation { cited_text, document_index, document_title, 4 more } or CitationContentBlockLocation { cited_text, document_index, document_title, 4 more } or 2 more
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "citations_delta"
ThinkingDelta = object { thinking, type }
type: "thinking_delta"
SignatureDelta = object { signature, type }
type: "signature_delta"
type: "content_block_delta"
RawContentBlockStartEvent = object { content_block, index, type }
content_block: TextBlock { citations, text, type } or ThinkingBlock { signature, thinking, type } or RedactedThinkingBlock { data, type } or 3 more
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
type: "content_block_start"
RawContentBlockStopEvent = object { index, type }
type: "content_block_stop"
RawMessageDeltaEvent = object { delta, type, usage }
delta: object { stop_reason, stop_sequence }
type: "message_delta"
usage: MessageDeltaUsage { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }
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.
cache_creation_input_tokens: number
The cumulative number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The cumulative number of input tokens read from the cache.
input_tokens: number
The cumulative number of input tokens which were used.
output_tokens: number
The cumulative number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
RawMessageStartEvent = object { message, type }
id: string
Unique object identifier.
The format and length of IDs may change over time.
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)"}]
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
The model that will complete your prompt.
See models for additional details and options.
UnionMember0 = "claude-opus-4-5-20251101" or "claude-opus-4-5" or "claude-3-7-sonnet-latest" or 17 more
The model that will complete your prompt.
See models for additional details and options.
"claude-opus-4-5-20251101"
Premium model combining maximum intelligence with practical performance
"claude-opus-4-5"
Premium model combining maximum intelligence with practical performance
"claude-3-7-sonnet-latest"
High-performance model with early extended thinking
"claude-3-7-sonnet-20250219"
High-performance model with early extended thinking
"claude-3-5-haiku-latest"
Fastest and most compact model for near-instant responsiveness
"claude-3-5-haiku-20241022"
Our fastest model
"claude-haiku-4-5"
Hybrid model, capable of near-instant responses and extended thinking
"claude-haiku-4-5-20251001"
Hybrid model, capable of near-instant responses and extended thinking
"claude-sonnet-4-20250514"
High-performance model with extended thinking
"claude-sonnet-4-0"
High-performance model with extended thinking
"claude-4-sonnet-20250514"
High-performance model with extended thinking
"claude-sonnet-4-5"
Our best model for real-world agents and coding
"claude-sonnet-4-5-20250929"
Our best model for real-world agents and coding
"claude-opus-4-0"
Our most capable model
"claude-opus-4-20250514"
Our most capable model
"claude-4-opus-20250514"
Our most capable model
"claude-opus-4-1-20250805"
Our most capable model
"claude-3-opus-latest"
Excels at writing and complex tasks
"claude-3-opus-20240229"
Excels at writing and complex tasks
"claude-3-haiku-20240307"
Our previous most fast and cost-effective
role: "assistant"
Conversational role of the generated message.
This will always be "assistant".
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 requestedmax_tokensor the model's maximum"stop_sequence": one of your provided customstop_sequenceswas 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.
stop_sequence: 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".
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.
Breakdown of cached tokens by TTL
ephemeral_1h_input_tokens: number
The number of input tokens used to create the 1 hour cache entry.
ephemeral_5m_input_tokens: number
The number of input tokens used to create the 5 minute cache entry.
cache_creation_input_tokens: number
The number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The number of input tokens read from the cache.
input_tokens: number
The number of input tokens which were used.
output_tokens: number
The number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
service_tier: "standard" or "priority" or "batch"
If the request used the priority, standard, or batch tier.
type: "message_start"
RawMessageStopEvent = object { type }
type: "message_stop"
RawMessageStreamEvent = RawMessageStartEvent { message, type } or RawMessageDeltaEvent { delta, type, usage } or RawMessageStopEvent { type } or 3 more
RawMessageStartEvent = object { message, type }
id: string
Unique object identifier.
The format and length of IDs may change over time.
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)"}]
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
The model that will complete your prompt.
See models for additional details and options.
UnionMember0 = "claude-opus-4-5-20251101" or "claude-opus-4-5" or "claude-3-7-sonnet-latest" or 17 more
The model that will complete your prompt.
See models for additional details and options.
"claude-opus-4-5-20251101"
Premium model combining maximum intelligence with practical performance
"claude-opus-4-5"
Premium model combining maximum intelligence with practical performance
"claude-3-7-sonnet-latest"
High-performance model with early extended thinking
"claude-3-7-sonnet-20250219"
High-performance model with early extended thinking
"claude-3-5-haiku-latest"
Fastest and most compact model for near-instant responsiveness
"claude-3-5-haiku-20241022"
Our fastest model
"claude-haiku-4-5"
Hybrid model, capable of near-instant responses and extended thinking
"claude-haiku-4-5-20251001"
Hybrid model, capable of near-instant responses and extended thinking
"claude-sonnet-4-20250514"
High-performance model with extended thinking
"claude-sonnet-4-0"
High-performance model with extended thinking
"claude-4-sonnet-20250514"
High-performance model with extended thinking
"claude-sonnet-4-5"
Our best model for real-world agents and coding
"claude-sonnet-4-5-20250929"
Our best model for real-world agents and coding
"claude-opus-4-0"
Our most capable model
"claude-opus-4-20250514"
Our most capable model
"claude-4-opus-20250514"
Our most capable model
"claude-opus-4-1-20250805"
Our most capable model
"claude-3-opus-latest"
Excels at writing and complex tasks
"claude-3-opus-20240229"
Excels at writing and complex tasks
"claude-3-haiku-20240307"
Our previous most fast and cost-effective
role: "assistant"
Conversational role of the generated message.
This will always be "assistant".
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 requestedmax_tokensor the model's maximum"stop_sequence": one of your provided customstop_sequenceswas 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.
stop_sequence: 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".
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.
Breakdown of cached tokens by TTL
ephemeral_1h_input_tokens: number
The number of input tokens used to create the 1 hour cache entry.
ephemeral_5m_input_tokens: number
The number of input tokens used to create the 5 minute cache entry.
cache_creation_input_tokens: number
The number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The number of input tokens read from the cache.
input_tokens: number
The number of input tokens which were used.
output_tokens: number
The number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
service_tier: "standard" or "priority" or "batch"
If the request used the priority, standard, or batch tier.
type: "message_start"
RawMessageDeltaEvent = object { delta, type, usage }
delta: object { stop_reason, stop_sequence }
type: "message_delta"
usage: MessageDeltaUsage { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }
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.
cache_creation_input_tokens: number
The cumulative number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The cumulative number of input tokens read from the cache.
input_tokens: number
The cumulative number of input tokens which were used.
output_tokens: number
The cumulative number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
RawMessageStopEvent = object { type }
type: "message_stop"
RawContentBlockStartEvent = object { content_block, index, type }
content_block: TextBlock { citations, text, type } or ThinkingBlock { signature, thinking, type } or RedactedThinkingBlock { data, type } or 3 more
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
type: "content_block_start"
RawContentBlockDeltaEvent = object { delta, index, type }
TextDelta = object { text, type }
type: "text_delta"
InputJSONDelta = object { partial_json, type }
type: "input_json_delta"
CitationsDelta = object { citation, type }
citation: CitationCharLocation { cited_text, document_index, document_title, 4 more } or CitationPageLocation { cited_text, document_index, document_title, 4 more } or CitationContentBlockLocation { cited_text, document_index, document_title, 4 more } or 2 more
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "citations_delta"
ThinkingDelta = object { thinking, type }
type: "thinking_delta"
SignatureDelta = object { signature, type }
type: "signature_delta"
type: "content_block_delta"
RawContentBlockStopEvent = object { index, type }
type: "content_block_stop"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
RedactedThinkingBlockParam = object { data, type }
type: "redacted_thinking"
SearchResultBlockParam = object { content, source, title, 3 more }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "search_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ServerToolUsage = object { web_search_requests }
web_search_requests: number
The number of web search tool requests.
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
ServerToolUseBlockParam = object { id, input, name, 2 more }
name: "web_search"
type: "server_tool_use"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
SignatureDelta = object { signature, type }
type: "signature_delta"
StopReason = "end_turn" or "max_tokens" or "stop_sequence" or 3 more
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
TextCitation = CitationCharLocation { cited_text, document_index, document_title, 4 more } or CitationPageLocation { cited_text, document_index, document_title, 4 more } or CitationContentBlockLocation { cited_text, document_index, document_title, 4 more } or 2 more
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
TextCitationParam = CitationCharLocationParam { cited_text, document_index, document_title, 3 more } or CitationPageLocationParam { cited_text, document_index, document_title, 3 more } or CitationContentBlockLocationParam { cited_text, document_index, document_title, 3 more } or 2 more
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
TextDelta = object { text, type }
type: "text_delta"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
ThinkingBlockParam = object { signature, thinking, type }
type: "thinking"
ThinkingConfigDisabled = object { type }
type: "disabled"
ThinkingConfigEnabled = object { budget_tokens, type }
budget_tokens: number
Determines how many tokens Claude can use for its internal reasoning process. Larger budgets can enable more thorough analysis for complex problems, improving response quality.
Must be ≥1024 and less than max_tokens.
See extended thinking for details.
type: "enabled"
ThinkingConfigParam = ThinkingConfigEnabled { budget_tokens, type } or ThinkingConfigDisabled { type }
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.
ThinkingConfigEnabled = object { budget_tokens, type }
budget_tokens: number
Determines how many tokens Claude can use for its internal reasoning process. Larger budgets can enable more thorough analysis for complex problems, improving response quality.
Must be ≥1024 and less than max_tokens.
See extended thinking for details.
type: "enabled"
ThinkingConfigDisabled = object { type }
type: "disabled"
ThinkingDelta = object { thinking, type }
type: "thinking_delta"
Tool = object { input_schema, name, cache_control, 2 more }
input_schema: object { type, properties, required }
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"
name: string
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
description: optional string
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.
type: optional "custom"
ToolBash20250124 = object { name, type, cache_control }
name: "bash"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "bash_20250124"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolChoice = ToolChoiceAuto { type, disable_parallel_tool_use } or ToolChoiceAny { type, disable_parallel_tool_use } or ToolChoiceTool { name, type, disable_parallel_tool_use } or ToolChoiceNone { type }
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.
ToolChoiceAuto = object { type, disable_parallel_tool_use }
The model will automatically decide whether to use tools.
type: "auto"
disable_parallel_tool_use: optional boolean
Whether to disable parallel tool use.
Defaults to false. If set to true, the model will output at most one tool use.
ToolChoiceAny = object { type, disable_parallel_tool_use }
The model will use any available tools.
type: "any"
disable_parallel_tool_use: optional boolean
Whether to disable parallel tool use.
Defaults to false. If set to true, the model will output exactly one tool use.
ToolChoiceTool = object { name, type, disable_parallel_tool_use }
The model will use the specified tool with tool_choice.name.
name: string
The name of the tool to use.
type: "tool"
disable_parallel_tool_use: optional boolean
Whether to disable parallel tool use.
Defaults to false. If set to true, the model will output exactly one tool use.
ToolChoiceNone = object { type }
The model will not be allowed to use tools.
type: "none"
ToolChoiceAny = object { type, disable_parallel_tool_use }
The model will use any available tools.
type: "any"
disable_parallel_tool_use: optional boolean
Whether to disable parallel tool use.
Defaults to false. If set to true, the model will output exactly one tool use.
ToolChoiceAuto = object { type, disable_parallel_tool_use }
The model will automatically decide whether to use tools.
type: "auto"
disable_parallel_tool_use: optional boolean
Whether to disable parallel tool use.
Defaults to false. If set to true, the model will output at most one tool use.
ToolChoiceNone = object { type }
The model will not be allowed to use tools.
type: "none"
ToolChoiceTool = object { name, type, disable_parallel_tool_use }
The model will use the specified tool with tool_choice.name.
name: string
The name of the tool to use.
type: "tool"
disable_parallel_tool_use: optional boolean
Whether to disable parallel tool use.
Defaults to false. If set to true, the model will output exactly one tool use.
ToolResultBlockParam = object { tool_use_id, type, cache_control, 2 more }
type: "tool_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
content: optional string or array of TextBlockParam { text, type, cache_control, citations } or ImageBlockParam { source, type, cache_control } or SearchResultBlockParam { content, source, title, 3 more } or DocumentBlockParam { source, type, cache_control, 3 more }
UnionMember1 = array of TextBlockParam { text, type, cache_control, citations } or ImageBlockParam { source, type, cache_control } or SearchResultBlockParam { content, source, title, 3 more } or DocumentBlockParam { source, type, cache_control, 3 more }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
SearchResultBlockParam = object { content, source, title, 3 more }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "search_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
DocumentBlockParam = object { source, type, cache_control, 3 more }
source: Base64PDFSource { data, media_type, type } or PlainTextSource { data, media_type, type } or ContentBlockSource { content, type } or URLPDFSource { type, url }
Base64PDFSource = object { data, media_type, type }
media_type: "application/pdf"
type: "base64"
PlainTextSource = object { data, media_type, type }
media_type: "text/plain"
type: "text"
ContentBlockSource = object { content, type }
TextBlockParam = object { text, type, cache_control, citations }
type: "text"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
CitationCharLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "char_location"
CitationPageLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "page_location"
CitationContentBlockLocationParam = object { cited_text, document_index, document_title, 3 more }
type: "content_block_location"
CitationWebSearchResultLocationParam = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationSearchResultLocationParam = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
ImageBlockParam = object { source, type, cache_control }
Base64ImageSource = object { data, media_type, type }
media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"
type: "base64"
URLImageSource = object { type, url }
type: "url"
type: "image"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
type: "content"
URLPDFSource = object { type, url }
type: "url"
type: "document"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolTextEditor20250124 = object { name, type, cache_control }
name: "str_replace_editor"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "text_editor_20250124"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolTextEditor20250429 = object { name, type, cache_control }
name: "str_replace_based_edit_tool"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "text_editor_20250429"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolTextEditor20250728 = object { name, type, cache_control, max_characters }
name: "str_replace_based_edit_tool"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "text_editor_20250728"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
max_characters: optional number
Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.
ToolUnion = Tool { input_schema, name, cache_control, 2 more } or ToolBash20250124 { name, type, cache_control } or ToolTextEditor20250124 { name, type, cache_control } or 3 more
Tool = object { input_schema, name, cache_control, 2 more }
input_schema: object { type, properties, required }
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"
name: string
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
description: optional string
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.
type: optional "custom"
ToolBash20250124 = object { name, type, cache_control }
name: "bash"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "bash_20250124"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolTextEditor20250124 = object { name, type, cache_control }
name: "str_replace_editor"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "text_editor_20250124"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolTextEditor20250429 = object { name, type, cache_control }
name: "str_replace_based_edit_tool"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "text_editor_20250429"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
ToolTextEditor20250728 = object { name, type, cache_control, max_characters }
name: "str_replace_based_edit_tool"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "text_editor_20250728"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
max_characters: optional number
Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.
WebSearchTool20250305 = object { name, type, allowed_domains, 4 more }
name: "web_search"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "web_search_20250305"
allowed_domains: optional array of string
If provided, only these domains will be included in results. Cannot be used alongside blocked_domains.
blocked_domains: optional array of string
If provided, these domains will never appear in results. Cannot be used alongside allowed_domains.
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
max_uses: optional number
Maximum number of times the tool can be used in the API request.
user_location: optional object { type, city, country, 2 more }
Parameters for the user's location. Used to provide more relevant search results.
type: "approximate"
city: optional string
The city of the user.
country: optional string
The two letter ISO country code of the user.
region: optional string
The region of the user.
timezone: optional string
The IANA timezone of the user.
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ToolUseBlockParam = object { id, input, name, 2 more }
type: "tool_use"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
URLImageSource = object { type, url }
type: "url"
URLPDFSource = object { type, url }
type: "url"
Usage = object { cache_creation, cache_creation_input_tokens, cache_read_input_tokens, 4 more }
Breakdown of cached tokens by TTL
ephemeral_1h_input_tokens: number
The number of input tokens used to create the 1 hour cache entry.
ephemeral_5m_input_tokens: number
The number of input tokens used to create the 5 minute cache entry.
cache_creation_input_tokens: number
The number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The number of input tokens read from the cache.
input_tokens: number
The number of input tokens which were used.
output_tokens: number
The number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
service_tier: "standard" or "priority" or "batch"
If the request used the priority, standard, or batch tier.
WebSearchResultBlock = object { encrypted_content, page_age, title, 2 more }
type: "web_search_result"
WebSearchResultBlockParam = object { encrypted_content, title, type, 2 more }
type: "web_search_result"
WebSearchTool20250305 = object { name, type, allowed_domains, 4 more }
name: "web_search"
Name of the tool.
This is how the tool will be called by the model and in tool_use blocks.
type: "web_search_20250305"
allowed_domains: optional array of string
If provided, only these domains will be included in results. Cannot be used alongside blocked_domains.
blocked_domains: optional array of string
If provided, these domains will never appear in results. Cannot be used alongside allowed_domains.
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
max_uses: optional number
Maximum number of times the tool can be used in the API request.
user_location: optional object { type, city, country, 2 more }
Parameters for the user's location. Used to provide more relevant search results.
type: "approximate"
city: optional string
The city of the user.
country: optional string
The two letter ISO country code of the user.
region: optional string
The region of the user.
timezone: optional string
The IANA timezone of the user.
WebSearchToolRequestError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
WebSearchToolResultBlockContent = WebSearchToolResultError { error_code, type } or array of WebSearchResultBlock { encrypted_content, page_age, title, 2 more }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
WebSearchToolResultBlockParam = object { content, tool_use_id, type, cache_control }
WebSearchToolResultBlockItem = array of WebSearchResultBlockParam { encrypted_content, title, type, 2 more }
type: "web_search_result"
WebSearchToolRequestError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_tool_result"
Create a cache control breakpoint at this content block.
type: "ephemeral"
ttl: optional "5m" or "1h"
The time-to-live for the cache control breakpoint.
This may be one the following values:
5m: 5 minutes1h: 1 hour
Defaults to 5m.
WebSearchToolResultBlockParamContent = array of WebSearchResultBlockParam { encrypted_content, title, type, 2 more } or WebSearchToolRequestError { error_code, type }
WebSearchToolResultBlockItem = array of WebSearchResultBlockParam { encrypted_content, title, type, 2 more }
type: "web_search_result"
WebSearchToolRequestError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
MessagesBatches
Create a Message Batch
Retrieve a Message Batch
List Message Batches
Cancel a Message Batch
Delete a Message Batch
Retrieve Message Batch results
ModelsExpand Collapse
DeletedMessageBatch = object { id, type }
id: string
ID of the Message Batch.
type: "message_batch_deleted"
Deleted object type.
For Message Batches, this is always "message_batch_deleted".
MessageBatch = object { id, archived_at, cancel_initiated_at, 7 more }
id: string
Unique object identifier.
The format and length of IDs may change over time.
archived_at: string
RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.
cancel_initiated_at: string
RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.
created_at: string
RFC 3339 datetime string representing the time at which the Message Batch was created.
ended_at: string
RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.
Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.
expires_at: string
RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.
processing_status: "in_progress" or "canceling" or "ended"
Processing status of the Message Batch.
Tallies requests within the Message Batch, categorized by their status.
Requests start as processing and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.
canceled: number
Number of requests in the Message Batch that have been canceled.
This is zero until processing of the entire Message Batch has ended.
errored: number
Number of requests in the Message Batch that encountered an error.
This is zero until processing of the entire Message Batch has ended.
expired: number
Number of requests in the Message Batch that have expired.
This is zero until processing of the entire Message Batch has ended.
processing: number
Number of requests in the Message Batch that are processing.
succeeded: number
Number of requests in the Message Batch that have completed successfully.
This is zero until processing of the entire Message Batch has ended.
results_url: string
URL to a .jsonl file containing the results of the Message Batch requests. Specified only once processing ends.
Results in the file are not guaranteed to be in the same order as requests. Use the custom_id field to match results to requests.
type: "message_batch"
Object type.
For Message Batches, this is always "message_batch".
MessageBatchCanceledResult = object { type }
type: "canceled"
MessageBatchErroredResult = object { error, type }
InvalidRequestError = object { message, type }
type: "invalid_request_error"
AuthenticationError = object { message, type }
type: "authentication_error"
BillingError = object { message, type }
type: "billing_error"
PermissionError = object { message, type }
type: "permission_error"
NotFoundError = object { message, type }
type: "not_found_error"
RateLimitError = object { message, type }
type: "rate_limit_error"
GatewayTimeoutError = object { message, type }
type: "timeout_error"
APIErrorObject = object { message, type }
type: "api_error"
OverloadedError = object { message, type }
type: "overloaded_error"
type: "error"
type: "errored"
MessageBatchExpiredResult = object { type }
type: "expired"
MessageBatchIndividualResponse = object { custom_id, result }
This is a single line in the response .jsonl file and does not represent the response as a whole.
custom_id: string
Developer-provided ID created for each request in a Message Batch. Useful for matching results to requests, as results may be given out of request order.
Must be unique for each request within the Message Batch.
Processing result for this request.
Contains a Message output if processing was successful, an error response if processing failed, or the reason why processing was not attempted, such as cancellation or expiration.
MessageBatchSucceededResult = object { message, type }
id: string
Unique object identifier.
The format and length of IDs may change over time.
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)"}]
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
The model that will complete your prompt.
See models for additional details and options.
UnionMember0 = "claude-opus-4-5-20251101" or "claude-opus-4-5" or "claude-3-7-sonnet-latest" or 17 more
The model that will complete your prompt.
See models for additional details and options.
"claude-opus-4-5-20251101"
Premium model combining maximum intelligence with practical performance
"claude-opus-4-5"
Premium model combining maximum intelligence with practical performance
"claude-3-7-sonnet-latest"
High-performance model with early extended thinking
"claude-3-7-sonnet-20250219"
High-performance model with early extended thinking
"claude-3-5-haiku-latest"
Fastest and most compact model for near-instant responsiveness
"claude-3-5-haiku-20241022"
Our fastest model
"claude-haiku-4-5"
Hybrid model, capable of near-instant responses and extended thinking
"claude-haiku-4-5-20251001"
Hybrid model, capable of near-instant responses and extended thinking
"claude-sonnet-4-20250514"
High-performance model with extended thinking
"claude-sonnet-4-0"
High-performance model with extended thinking
"claude-4-sonnet-20250514"
High-performance model with extended thinking
"claude-sonnet-4-5"
Our best model for real-world agents and coding
"claude-sonnet-4-5-20250929"
Our best model for real-world agents and coding
"claude-opus-4-0"
Our most capable model
"claude-opus-4-20250514"
Our most capable model
"claude-4-opus-20250514"
Our most capable model
"claude-opus-4-1-20250805"
Our most capable model
"claude-3-opus-latest"
Excels at writing and complex tasks
"claude-3-opus-20240229"
Excels at writing and complex tasks
"claude-3-haiku-20240307"
Our previous most fast and cost-effective
role: "assistant"
Conversational role of the generated message.
This will always be "assistant".
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 requestedmax_tokensor the model's maximum"stop_sequence": one of your provided customstop_sequenceswas 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.
stop_sequence: 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".
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.
Breakdown of cached tokens by TTL
ephemeral_1h_input_tokens: number
The number of input tokens used to create the 1 hour cache entry.
ephemeral_5m_input_tokens: number
The number of input tokens used to create the 5 minute cache entry.
cache_creation_input_tokens: number
The number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The number of input tokens read from the cache.
input_tokens: number
The number of input tokens which were used.
output_tokens: number
The number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
service_tier: "standard" or "priority" or "batch"
If the request used the priority, standard, or batch tier.
type: "succeeded"
MessageBatchErroredResult = object { error, type }
InvalidRequestError = object { message, type }
type: "invalid_request_error"
AuthenticationError = object { message, type }
type: "authentication_error"
BillingError = object { message, type }
type: "billing_error"
PermissionError = object { message, type }
type: "permission_error"
NotFoundError = object { message, type }
type: "not_found_error"
RateLimitError = object { message, type }
type: "rate_limit_error"
GatewayTimeoutError = object { message, type }
type: "timeout_error"
APIErrorObject = object { message, type }
type: "api_error"
OverloadedError = object { message, type }
type: "overloaded_error"
type: "error"
type: "errored"
MessageBatchCanceledResult = object { type }
type: "canceled"
MessageBatchExpiredResult = object { type }
type: "expired"
MessageBatchRequestCounts = object { canceled, errored, expired, 2 more }
canceled: number
Number of requests in the Message Batch that have been canceled.
This is zero until processing of the entire Message Batch has ended.
errored: number
Number of requests in the Message Batch that encountered an error.
This is zero until processing of the entire Message Batch has ended.
expired: number
Number of requests in the Message Batch that have expired.
This is zero until processing of the entire Message Batch has ended.
processing: number
Number of requests in the Message Batch that are processing.
succeeded: number
Number of requests in the Message Batch that have completed successfully.
This is zero until processing of the entire Message Batch has ended.
MessageBatchResult = MessageBatchSucceededResult { message, type } or MessageBatchErroredResult { error, type } or MessageBatchCanceledResult { type } or MessageBatchExpiredResult { type }
Processing result for this request.
Contains a Message output if processing was successful, an error response if processing failed, or the reason why processing was not attempted, such as cancellation or expiration.
MessageBatchSucceededResult = object { message, type }
id: string
Unique object identifier.
The format and length of IDs may change over time.
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)"}]
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
The model that will complete your prompt.
See models for additional details and options.
UnionMember0 = "claude-opus-4-5-20251101" or "claude-opus-4-5" or "claude-3-7-sonnet-latest" or 17 more
The model that will complete your prompt.
See models for additional details and options.
"claude-opus-4-5-20251101"
Premium model combining maximum intelligence with practical performance
"claude-opus-4-5"
Premium model combining maximum intelligence with practical performance
"claude-3-7-sonnet-latest"
High-performance model with early extended thinking
"claude-3-7-sonnet-20250219"
High-performance model with early extended thinking
"claude-3-5-haiku-latest"
Fastest and most compact model for near-instant responsiveness
"claude-3-5-haiku-20241022"
Our fastest model
"claude-haiku-4-5"
Hybrid model, capable of near-instant responses and extended thinking
"claude-haiku-4-5-20251001"
Hybrid model, capable of near-instant responses and extended thinking
"claude-sonnet-4-20250514"
High-performance model with extended thinking
"claude-sonnet-4-0"
High-performance model with extended thinking
"claude-4-sonnet-20250514"
High-performance model with extended thinking
"claude-sonnet-4-5"
Our best model for real-world agents and coding
"claude-sonnet-4-5-20250929"
Our best model for real-world agents and coding
"claude-opus-4-0"
Our most capable model
"claude-opus-4-20250514"
Our most capable model
"claude-4-opus-20250514"
Our most capable model
"claude-opus-4-1-20250805"
Our most capable model
"claude-3-opus-latest"
Excels at writing and complex tasks
"claude-3-opus-20240229"
Excels at writing and complex tasks
"claude-3-haiku-20240307"
Our previous most fast and cost-effective
role: "assistant"
Conversational role of the generated message.
This will always be "assistant".
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 requestedmax_tokensor the model's maximum"stop_sequence": one of your provided customstop_sequenceswas 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.
stop_sequence: 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".
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.
Breakdown of cached tokens by TTL
ephemeral_1h_input_tokens: number
The number of input tokens used to create the 1 hour cache entry.
ephemeral_5m_input_tokens: number
The number of input tokens used to create the 5 minute cache entry.
cache_creation_input_tokens: number
The number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The number of input tokens read from the cache.
input_tokens: number
The number of input tokens which were used.
output_tokens: number
The number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
service_tier: "standard" or "priority" or "batch"
If the request used the priority, standard, or batch tier.
type: "succeeded"
MessageBatchErroredResult = object { error, type }
InvalidRequestError = object { message, type }
type: "invalid_request_error"
AuthenticationError = object { message, type }
type: "authentication_error"
BillingError = object { message, type }
type: "billing_error"
PermissionError = object { message, type }
type: "permission_error"
NotFoundError = object { message, type }
type: "not_found_error"
RateLimitError = object { message, type }
type: "rate_limit_error"
GatewayTimeoutError = object { message, type }
type: "timeout_error"
APIErrorObject = object { message, type }
type: "api_error"
OverloadedError = object { message, type }
type: "overloaded_error"
type: "error"
type: "errored"
MessageBatchCanceledResult = object { type }
type: "canceled"
MessageBatchExpiredResult = object { type }
type: "expired"
MessageBatchSucceededResult = object { message, type }
id: string
Unique object identifier.
The format and length of IDs may change over time.
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)"}]
TextBlock = object { citations, text, type }
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.
CitationCharLocation = object { cited_text, document_index, document_title, 4 more }
type: "char_location"
CitationPageLocation = object { cited_text, document_index, document_title, 4 more }
type: "page_location"
CitationContentBlockLocation = object { cited_text, document_index, document_title, 4 more }
type: "content_block_location"
CitationsWebSearchResultLocation = object { cited_text, encrypted_index, title, 2 more }
type: "web_search_result_location"
CitationsSearchResultLocation = object { cited_text, end_block_index, search_result_index, 4 more }
type: "search_result_location"
type: "text"
ThinkingBlock = object { signature, thinking, type }
type: "thinking"
RedactedThinkingBlock = object { data, type }
type: "redacted_thinking"
ToolUseBlock = object { id, input, name, type }
type: "tool_use"
ServerToolUseBlock = object { id, input, name, type }
name: "web_search"
type: "server_tool_use"
WebSearchToolResultBlock = object { content, tool_use_id, type }
WebSearchToolResultError = object { error_code, type }
error_code: "invalid_tool_input" or "unavailable" or "max_uses_exceeded" or 2 more
type: "web_search_tool_result_error"
type: "web_search_result"
type: "web_search_tool_result"
The model that will complete your prompt.
See models for additional details and options.
UnionMember0 = "claude-opus-4-5-20251101" or "claude-opus-4-5" or "claude-3-7-sonnet-latest" or 17 more
The model that will complete your prompt.
See models for additional details and options.
"claude-opus-4-5-20251101"
Premium model combining maximum intelligence with practical performance
"claude-opus-4-5"
Premium model combining maximum intelligence with practical performance
"claude-3-7-sonnet-latest"
High-performance model with early extended thinking
"claude-3-7-sonnet-20250219"
High-performance model with early extended thinking
"claude-3-5-haiku-latest"
Fastest and most compact model for near-instant responsiveness
"claude-3-5-haiku-20241022"
Our fastest model
"claude-haiku-4-5"
Hybrid model, capable of near-instant responses and extended thinking
"claude-haiku-4-5-20251001"
Hybrid model, capable of near-instant responses and extended thinking
"claude-sonnet-4-20250514"
High-performance model with extended thinking
"claude-sonnet-4-0"
High-performance model with extended thinking
"claude-4-sonnet-20250514"
High-performance model with extended thinking
"claude-sonnet-4-5"
Our best model for real-world agents and coding
"claude-sonnet-4-5-20250929"
Our best model for real-world agents and coding
"claude-opus-4-0"
Our most capable model
"claude-opus-4-20250514"
Our most capable model
"claude-4-opus-20250514"
Our most capable model
"claude-opus-4-1-20250805"
Our most capable model
"claude-3-opus-latest"
Excels at writing and complex tasks
"claude-3-opus-20240229"
Excels at writing and complex tasks
"claude-3-haiku-20240307"
Our previous most fast and cost-effective
role: "assistant"
Conversational role of the generated message.
This will always be "assistant".
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 requestedmax_tokensor the model's maximum"stop_sequence": one of your provided customstop_sequenceswas 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.
stop_sequence: 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".
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.
Breakdown of cached tokens by TTL
ephemeral_1h_input_tokens: number
The number of input tokens used to create the 1 hour cache entry.
ephemeral_5m_input_tokens: number
The number of input tokens used to create the 5 minute cache entry.
cache_creation_input_tokens: number
The number of input tokens used to create the cache entry.
cache_read_input_tokens: number
The number of input tokens read from the cache.
input_tokens: number
The number of input tokens which were used.
output_tokens: number
The number of output tokens which were used.
The number of server tool requests.
web_search_requests: number
The number of web search tool requests.
service_tier: "standard" or "priority" or "batch"
If the request used the priority, standard, or batch tier.