--- title: Send Events url: https://platform.claude.com/docs/en/api/beta/sessions/events/send --- # Send Events **POST** `/v1/sessions/{session_id}/events` Send Events ## Path parameters - `session_id: string` ## Headers - `"anthropic-version": optional string` The version of the Claude API you want to use. Read more about versioning and our version history [here](https://platform.claude.com/docs/en/api/versioning?sdk_languages=http). - `"anthropic-beta": optional array of AnthropicBeta` This endpoint is in beta: requests must send `managed-agents-2026-04-01` in this header. - `string` - `"message-batches-2024-09-24"` - `"prompt-caching-2024-07-31"` - `"computer-use-2024-10-22"` - `"computer-use-2025-01-24"` - `"pdfs-2024-09-25"` - `"token-counting-2024-11-01"` - `"token-efficient-tools-2025-02-19"` - `"output-128k-2025-02-19"` - `"files-api-2025-04-14"` - `"mcp-client-2025-04-04"` - `"mcp-client-2025-11-20"` - `"dev-full-thinking-2025-05-14"` - `"interleaved-thinking-2025-05-14"` - `"code-execution-2025-05-22"` - `"extended-cache-ttl-2025-04-11"` - `"context-1m-2025-08-07"` - `"context-management-2025-06-27"` - `"model-context-window-exceeded-2025-08-26"` - `"skills-2025-10-02"` - `"fast-mode-2026-02-01"` - `"output-300k-2026-03-24"` - `"user-profiles-2026-03-24"` - `"user-profiles-2026-08-18"` - `"user-profiles-2026-09-04"` - `"advisor-tool-2026-03-01"` - `"managed-agents-2026-04-01"` - `"cache-diagnosis-2026-04-07"` - `"dreaming-2026-04-21"` - `"thinking-token-count-2026-05-13"` - `"server-side-fallback-2026-06-01"` - `"server-side-fallback-2026-07-01"` - `"fallback-credit-2026-06-01"` - `"fallback-credit-2026-07-01"` - `"agent-memory-2026-07-22"` - `"mid-conversation-tool-changes-2026-07-01"` - `"compact-2026-01-12"` - `"computer-use-2025-11-24"` - `"mcp-tunnels-2026-06-22"` - `"structured-outputs-2025-11-13"` - `"task-budgets-2026-03-13"` - `"thinking-display-updates-2026-08-18"` - `"ce-user-management-2026-07-13"` - `"mid-conversation-output-config-2026-07-01"` - `"thinking-binding-controls-2026-08-01"` - `"mid-conversation-system-clear-at-2026-08-21"` - `"compact-2026-09-04"` - `"inline-tools-2026-09-15"` - `"mcp-client-2026-09-15"` - `"ce-plugins-2026-09-01"` - `"spend-limit-reads-2026-09-26"` - `"telemetry-destinations-2026-08-11"` - `"anthropic-workspace-id": optional string` Optional header to select the Workspace for this request. The value is a Workspace ID (for example, `wrkspc_011CZkZaBF1tNoB5wlCeusgy`). Only needed for credentials that can act on more than one Workspace. A credential that belongs to a specific Workspace may omit it; if sent, it must match that Workspace. ## Body parameters - `events: array of BetaManagedAgentsEventParams` Events to send to the `session`. - `BetaManagedAgentsUserMessageEventParams object` Parameters for sending a user message to the session. - `type: "user.message"` - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsRedactedBlock` Array of content blocks for the user message. - `BetaManagedAgentsTextBlock object` Regular text content. - `type: "text"` - `text: string` The text content. minLength: 1 - `BetaManagedAgentsImageBlock object` Image content specified directly as base64 data or as a reference via a URL. - `type: "image"` - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource` The source of the image data. - `BetaManagedAgentsBase64ImageSource object` Base64-encoded image data. - `type: "base64"` - `data: string` Base64-encoded image data. minLength: 1 - `media_type: string` MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp"). minLength: 1 - `BetaManagedAgentsURLImageSource object` Image referenced by URL. - `type: "url"` - `url: string` URL of the image to fetch. minLength: 1 - `BetaManagedAgentsFileImageSource object` Image referenced by file ID. - `type: "file"` - `file_id: string` ID of a previously uploaded file. minLength: 1 - `BetaManagedAgentsDocumentBlock object` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type: "document"` - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource` The source of the document data. - `BetaManagedAgentsBase64DocumentSource object` Base64-encoded document data. - `type: "base64"` - `data: string` Base64-encoded document data. minLength: 1 - `media_type: string` MIME type of the document (e.g., "application/pdf"). minLength: 1 - `BetaManagedAgentsPlainTextDocumentSource object` Plain text document content. - `type: "text"` - `data: string` The plain text content. minLength: 1 - `media_type: "text/plain"` MIME type of the text content. Must be "text/plain". - `BetaManagedAgentsURLDocumentSource object` Document referenced by URL. - `type: "url"` - `url: string` URL of the document to fetch. minLength: 1 - `BetaManagedAgentsFileDocumentSource object` Document referenced by file ID. - `type: "file"` - `file_id: string` ID of a previously uploaded file. minLength: 1 - `context: optional string or null` Additional context about the document for the model. - `title: optional string or null` The title of the document. - `BetaManagedAgentsRedactedBlock object` Placeholder for content withheld by Anthropic model policy. - `type: "redacted"` - `BetaManagedAgentsUserInterruptEventParams object` Parameters for sending an interrupt to pause the agent. - `type: "user.interrupt"` - `session_thread_id: optional string or null` If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread. - `BetaManagedAgentsUserToolConfirmationEventParams object` Parameters for confirming or denying a tool execution request. - `type: "user.tool_confirmation"` - `result: "allow" or "deny"` The confirmation result: 'allow' or 'deny'. - `"allow"` - `"deny"` - `tool_use_id: string` The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=http#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. minLength: 1, maxLength: 128 - `deny_message: optional string or null` Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'. maxLength: 10000 - `BetaManagedAgentsUserCustomToolResultEventParams object` Parameters for providing the result of a custom tool execution. - `type: "user.custom_tool_result"` - `custom_tool_use_id: string` The id of the `agent.custom_tool_use` event this result corresponds to. It is also listed in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=http#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. minLength: 1, maxLength: 128 - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock` The result content returned by the tool. - `BetaManagedAgentsTextBlock object` Regular text content. - `BetaManagedAgentsImageBlock object` Image content specified directly as base64 data or as a reference via a URL. - `BetaManagedAgentsDocumentBlock object` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `BetaManagedAgentsSearchResultBlock object` A block containing a web search result. - `type: "search_result"` - `citations: BetaManagedAgentsSearchResultCitations` Citation settings for this search result. - `enabled: boolean` Whether citations are enabled for this search result. - `content: array of BetaManagedAgentsSearchResultContent` Array of text content blocks from the search result. - `type: "text"` - `text: string` The text content. minLength: 1 - `source: string` The URL source of the search result. minLength: 1 - `title: string` The title of the search result. minLength: 1 - `is_error: optional boolean or null` Whether the tool execution resulted in an error. - `BetaManagedAgentsUserDefineOutcomeEventParams object` Parameters for defining an outcome the agent should work toward. The agent begins work on receipt. - `type: "user.define_outcome"` - `description: string` What the agent should produce. This is the task specification. - `rubric: BetaManagedAgentsFileRubricParams or BetaManagedAgentsTextRubricParams` How to grade the outcome. Text or file reference. - `BetaManagedAgentsFileRubricParams object` Rubric referenced by a file uploaded via the Files API. - `type: "file"` - `file_id: string` ID of the rubric file. - `BetaManagedAgentsTextRubricParams object` Rubric content provided inline as text. - `type: "text"` - `content: string` Rubric content. Plain text or markdown — the grader treats it as freeform text. Maximum 262144 characters. maxLength: 262144 - `max_iterations: optional number or null` Eval→revision cycles before giving up. Default 3, max 20. format: int32 - `BetaManagedAgentsUserToolResultEventParams object` Parameters for providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server. - `type: "user.tool_result"` - `tool_use_id: string` The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=http#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. minLength: 1, maxLength: 128 - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock` The result content returned by the tool. - `BetaManagedAgentsTextBlock object` Regular text content. - `BetaManagedAgentsImageBlock object` Image content specified directly as base64 data or as a reference via a URL. - `BetaManagedAgentsDocumentBlock object` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `BetaManagedAgentsSearchResultBlock object` A block containing a web search result. - `is_error: optional boolean or null` Whether the tool execution resulted in an error. - `BetaManagedAgentsSystemMessageEventParams object` Privileged context for the accompanying turn and all subsequent turns, appended to the session's system context as a `role: "system"` turn rather than replacing the top-level system prompt. At most one per request: it must be the final event and immediately follow the `user.message`, `user.tool_result`, or `user.custom_tool_result` it accompanies. Only supported on models that accept mid-conversation system messages. - `type: "system.message"` - `content: array of BetaManagedAgentsSystemContentBlock` System content blocks to append. Text-only. - `type: "text"` - `text: string` The text content. minLength: 1 ## Returns - `BetaManagedAgentsSendSessionEvents object` Events that were successfully sent to the session. - `data: optional array of BetaManagedAgentsUserMessageEvent or BetaManagedAgentsUserInterruptEvent or BetaManagedAgentsUserToolConfirmationEvent or 4 more` Sent events - `BetaManagedAgentsUserMessageEvent object` A user message event in the session conversation. - `type: "user.message"` - `id: string` Unique identifier for this event. - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsRedactedBlock` Array of content blocks comprising the user message. - `BetaManagedAgentsTextBlock object` Regular text content. - `type: "text"` - `text: string` The text content. minLength: 1 - `BetaManagedAgentsImageBlock object` Image content specified directly as base64 data or as a reference via a URL. - `type: "image"` - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource` The source of the image data. - `BetaManagedAgentsBase64ImageSource object` Base64-encoded image data. - `type: "base64"` - `data: string` Base64-encoded image data. minLength: 1 - `media_type: string` MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp"). minLength: 1 - `BetaManagedAgentsURLImageSource object` Image referenced by URL. - `type: "url"` - `url: string` URL of the image to fetch. minLength: 1 - `BetaManagedAgentsFileImageSource object` Image referenced by file ID. - `type: "file"` - `file_id: string` ID of a previously uploaded file. minLength: 1 - `BetaManagedAgentsDocumentBlock object` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type: "document"` - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource` The source of the document data. - `BetaManagedAgentsBase64DocumentSource object` Base64-encoded document data. - `type: "base64"` - `data: string` Base64-encoded document data. minLength: 1 - `media_type: string` MIME type of the document (e.g., "application/pdf"). minLength: 1 - `BetaManagedAgentsPlainTextDocumentSource object` Plain text document content. - `type: "text"` - `data: string` The plain text content. minLength: 1 - `media_type: "text/plain"` MIME type of the text content. Must be "text/plain". - `BetaManagedAgentsURLDocumentSource object` Document referenced by URL. - `type: "url"` - `url: string` URL of the document to fetch. minLength: 1 - `BetaManagedAgentsFileDocumentSource object` Document referenced by file ID. - `type: "file"` - `file_id: string` ID of a previously uploaded file. minLength: 1 - `context: optional string or null` Additional context about the document for the model. - `title: optional string or null` The title of the document. - `BetaManagedAgentsRedactedBlock object` Placeholder for content withheld by Anthropic model policy. - `type: "redacted"` - `processed_at: optional string or null` Timestamp when the agent finished processing this message. format: date-time - `BetaManagedAgentsUserInterruptEvent object` An interrupt event that pauses agent execution and returns control to the user. - `type: "user.interrupt"` - `id: string` Unique identifier for this event. - `processed_at: optional string or null` Timestamp when the interrupt was processed. format: date-time - `session_thread_id: optional string or null` If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread. - `BetaManagedAgentsUserToolConfirmationEvent object` A tool confirmation event that approves or denies a pending tool execution. - `type: "user.tool_confirmation"` - `id: string` Unique identifier for this event. - `result: "allow" or "deny"` The confirmation result: 'allow' or 'deny'. - `"allow"` - `"deny"` - `tool_use_id: string` The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=http#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. - `deny_message: optional string or null` Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'. maxLength: 10000 - `processed_at: optional string or null` Timestamp when the confirmation was processed. format: date-time - `session_thread_id: optional string or null` Set by the server to the subagent thread this confirmation was routed to. Omitted when it was routed to the primary thread. - `BetaManagedAgentsUserCustomToolResultEvent object` Event sent by the client providing the result of a custom tool execution. - `type: "user.custom_tool_result"` - `id: string` Unique identifier for this event. - `custom_tool_use_id: string` The id of the `agent.custom_tool_use` event this result corresponds to. It is also listed in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=http#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock` The result content returned by the tool. - `BetaManagedAgentsTextBlock object` Regular text content. - `BetaManagedAgentsImageBlock object` Image content specified directly as base64 data or as a reference via a URL. - `BetaManagedAgentsDocumentBlock object` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `BetaManagedAgentsSearchResultBlock object` A block containing a web search result. - `type: "search_result"` - `citations: BetaManagedAgentsSearchResultCitations` Citation settings for this search result. - `enabled: boolean` Whether citations are enabled for this search result. - `content: array of BetaManagedAgentsSearchResultContent` Array of text content blocks from the search result. - `type: "text"` - `text: string` The text content. minLength: 1 - `source: string` The URL source of the search result. minLength: 1 - `title: string` The title of the search result. minLength: 1 - `is_error: optional boolean or null` Whether the tool execution resulted in an error. - `processed_at: optional string or null` Timestamp when this result was processed. format: date-time - `session_thread_id: optional string or null` Set by the server to the subagent thread this result was routed to. Omitted when it was routed to the primary thread. - `BetaManagedAgentsUserDefineOutcomeEvent object` Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference. - `type: "user.define_outcome"` - `id: string` Unique identifier for this event. - `description: string` What the agent should produce. Copied from the input event. - `max_iterations: number or null` Evaluate-then-revise cycles before giving up. Default 3, max 20. format: int32 - `outcome_id: string` Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list. - `processed_at: string` Timestamp when the outcome was accepted. format: date-time - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric` How to grade the outcome. File rubrics are currently resolved to their text content; clients should handle both variants. - `BetaManagedAgentsFileRubric object` Rubric referenced by a file uploaded via the Files API. - `type: "file"` - `file_id: string` ID of the rubric file. - `BetaManagedAgentsTextRubric object` Rubric content provided inline as text. - `type: "text"` - `content: string` Rubric content. Plain text or markdown — the grader treats it as freeform text. - `BetaManagedAgentsUserToolResultEvent object` Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server. - `type: "user.tool_result"` - `id: string` Unique identifier for this event. - `tool_use_id: string` The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=http#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock` The result content returned by the tool. - `BetaManagedAgentsTextBlock object` Regular text content. - `BetaManagedAgentsImageBlock object` Image content specified directly as base64 data or as a reference via a URL. - `BetaManagedAgentsDocumentBlock object` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `BetaManagedAgentsSearchResultBlock object` A block containing a web search result. - `is_error: optional boolean or null` Whether the tool execution resulted in an error. - `processed_at: optional string or null` Timestamp when this result was processed. format: date-time - `session_thread_id: optional string or null` Set by the server to the subagent thread this result was routed to. Omitted when it was routed to the primary thread. - `BetaManagedAgentsSystemMessageEvent object` A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn. - `type: "system.message"` - `id: string` Unique identifier for this event. - `content: array of BetaManagedAgentsSystemContentBlock` System content blocks. Text-only. - `type: "text"` - `text: string` The text content. minLength: 1 - `processed_at: optional string or null` Timestamp when this system message was processed. format: date-time ## Example ```bash curl https://api.anthropic.com/v1/sessions/$SESSION_ID/events \ -H 'Content-Type: application/json' \ -H 'anthropic-version: 2023-06-01' \ -H 'anthropic-beta: managed-agents-2026-04-01' \ -H "X-Api-Key: $ANTHROPIC_API_KEY" \ -d '{ "events": [ { "content": [ { "text": "Where is my order #1234?", "type": "text" } ], "type": "user.message" } ] }' ``` ### Response (200) ```json { "data": [ { "id": "sevt_011CZkZGPp1iBcp4kaQSihUm", "content": [ { "text": "Where is my order #1234?", "type": "text" } ], "type": "user.message", "processed_at": "2026-03-15T10:00:00Z" } ] } ```