--- title: "Stream Events" method: GET path: "/v1/sessions/{session_id}/events/stream?beta=true" --- # Stream Events `GET /v1/sessions/{session_id}/events/stream?beta=true` ## Path parameters - `session_id` string, required ## Headers - `x-api-key` string - `anthropic-version` string - `anthropic-beta` string ## Response `200` Successful response (OK) - union — Server-sent event in the session stream. - object — A user message event in the session conversation. - `type` 'user.message', required - `id` string, required — Unique identifier for this event. - `content` BetaManagedAgentsUserContentBlock[], required — Array of content blocks comprising the user message. - union — Content block in a user message. Can be `text`, `image`, or `document`. - object — Regular text content. - `type` 'text', required - `text` string, required — The text content. - object — Image content specified directly as base64 data or as a reference via a URL. - `type` 'image', required - `source` union, required — Union type for image source variants. - object — Base64-encoded image data. - … - object — Image referenced by URL. - … - object — Image referenced by file ID. - … - object — Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type` 'document', required - `source` union, required — Union type for document source variants. - object — Base64-encoded document data. - … - object — Plain text document content. - … - object — Document referenced by URL. - … - object — Document referenced by file ID. - … - `title` string, nullable — The title of the document. - `context` string, nullable — Additional context about the document for the model. - `processed_at` string, date-time — A timestamp in RFC 3339 format - object — An interrupt event that pauses agent execution and returns control to the user. - `type` 'user.interrupt', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time — A timestamp in RFC 3339 format - `session_thread_id` string, nullable — 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. - object — A tool confirmation event that approves or denies a pending tool execution. - `type` 'user.tool_confirmation', required - `id` string, required — Unique identifier for this event. - `tool_use_id` string, required — 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#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. - `result` 'allow' | 'deny', required — UserToolConfirmationResult enum - `deny_message` string, nullable — Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'. - `processed_at` string, date-time — A timestamp in RFC 3339 format - `session_thread_id` string, nullable — When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval. - object — Event sent by the client providing the result of a custom tool execution. - `type` 'user.custom_tool_result', required - `id` string, required — Unique identifier for this event. - `custom_tool_use_id` string, required — The id of the `agent.custom_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#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. - `content` BetaManagedAgentsToolResultContentBlock[] — The result content returned by the tool. - union — Content block in a tool result. Can be `text`, `image`, `document`, or `search_result`. - object — Regular text content. - `type` 'text', required - `text` string, required — The text content. - object — Image content specified directly as base64 data or as a reference via a URL. - `type` 'image', required - `source` union, required — Union type for image source variants. - object — Base64-encoded image data. - … - object — Image referenced by URL. - … - object — Image referenced by file ID. - … - object — Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type` 'document', required - `source` union, required — Union type for document source variants. - object — Base64-encoded document data. - … - object — Plain text document content. - … - object — Document referenced by URL. - … - object — Document referenced by file ID. - … - `title` string, nullable — The title of the document. - `context` string, nullable — Additional context about the document for the model. - object — A block containing a web search result. - `type` 'search_result', required - `source` string, required — The URL source of the search result. - `title` string, required — The title of the search result. - `content` BetaManagedAgentsSearchResultContent[], required — Array of text content blocks from the search result. - `type` 'text', required - `text` string, required — The text content. - `citations` BetaManagedAgentsSearchResultCitations, required — Citation settings for a search result. - `enabled` boolean, required — Whether citations are enabled for this search result. - `is_error` boolean, nullable — Whether the tool execution resulted in an error. - `processed_at` string, date-time — A timestamp in RFC 3339 format - `session_thread_id` string, nullable — Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`. - object — Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result. - `type` 'agent.custom_tool_use', required - `id` string, required — Unique identifier for this event. - `name` string, required — Name of the custom tool being called. - `input` BetaManagedAgentsStruct, required - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `session_thread_id` string, nullable — When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back. - object — An agent response event in the session conversation. - `type` 'agent.message', required - `id` string, required — Unique identifier for this event. - `content` BetaManagedAgentsTextBlock[], required — Array of text blocks comprising the agent response. - `type` 'text', required - `text` string, required — The text content. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier. - `type` 'agent.thinking', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — Event emitted when the agent invokes a tool provided by an MCP server. - `type` 'agent.mcp_tool_use', required - `id` string, required — Unique identifier for this event. - `name` string, required — Name of the MCP tool being used. - `mcp_server_name` string, required — Name of the MCP server providing the tool. - `input` BetaManagedAgentsStruct, required - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `evaluated_permission` 'allow' | 'ask' | 'deny' — AgentEvaluatedPermission enum - `session_thread_id` string, nullable — When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back. - object — Event representing the result of an MCP tool execution. - `type` 'agent.mcp_tool_result', required - `id` string, required — Unique identifier for this event. - `mcp_tool_use_id` string, required — The id of the `agent.mcp_tool_use` event this result corresponds to. - `content` BetaManagedAgentsToolResultContentBlock[] — The result content returned by the tool. - union — Content block in a tool result. Can be `text`, `image`, `document`, or `search_result`. - object — Regular text content. - `type` 'text', required - `text` string, required — The text content. - object — Image content specified directly as base64 data or as a reference via a URL. - `type` 'image', required - `source` union, required — Union type for image source variants. - object — Base64-encoded image data. - … - object — Image referenced by URL. - … - object — Image referenced by file ID. - … - object — Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type` 'document', required - `source` union, required — Union type for document source variants. - object — Base64-encoded document data. - … - object — Plain text document content. - … - object — Document referenced by URL. - … - object — Document referenced by file ID. - … - `title` string, nullable — The title of the document. - `context` string, nullable — Additional context about the document for the model. - object — A block containing a web search result. - `type` 'search_result', required - `source` string, required — The URL source of the search result. - `title` string, required — The title of the search result. - `content` BetaManagedAgentsSearchResultContent[], required — Array of text content blocks from the search result. - `type` 'text', required - `text` string, required — The text content. - `citations` BetaManagedAgentsSearchResultCitations, required — Citation settings for a search result. - `enabled` boolean, required — Whether citations are enabled for this search result. - `is_error` boolean, nullable — Whether the tool execution resulted in an error. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — Event emitted when the agent invokes a built-in agent tool. - `type` 'agent.tool_use', required - `id` string, required — Unique identifier for this event. - `name` string, required — Name of the agent tool being used. - `input` BetaManagedAgentsStruct, required - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `evaluated_permission` 'allow' | 'ask' | 'deny' — AgentEvaluatedPermission enum - `session_thread_id` string, nullable — When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back. - object — Event representing the result of an agent tool execution. - `type` 'agent.tool_result', required - `id` string, required — Unique identifier for this event. - `tool_use_id` string, required — The id of the `agent.tool_use` event this result corresponds to. - `content` BetaManagedAgentsToolResultContentBlock[] — The result content returned by the tool. - union — Content block in a tool result. Can be `text`, `image`, `document`, or `search_result`. - object — Regular text content. - `type` 'text', required - `text` string, required — The text content. - object — Image content specified directly as base64 data or as a reference via a URL. - `type` 'image', required - `source` union, required — Union type for image source variants. - object — Base64-encoded image data. - … - object — Image referenced by URL. - … - object — Image referenced by file ID. - … - object — Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type` 'document', required - `source` union, required — Union type for document source variants. - object — Base64-encoded document data. - … - object — Plain text document content. - … - object — Document referenced by URL. - … - object — Document referenced by file ID. - … - `title` string, nullable — The title of the document. - `context` string, nullable — Additional context about the document for the model. - object — A block containing a web search result. - `type` 'search_result', required - `source` string, required — The URL source of the search result. - `title` string, required — The title of the search result. - `content` BetaManagedAgentsSearchResultContent[], required — Array of text content blocks from the search result. - `type` 'text', required - `text` string, required — The text content. - `citations` BetaManagedAgentsSearchResultCitations, required — Citation settings for a search result. - `enabled` boolean, required — Whether citations are enabled for this search result. - `is_error` boolean, nullable — Whether the tool execution resulted in an error. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — Delivery event written to the target thread's input stream when an agent-to-agent message arrives. - `type` 'agent.thread_message_received', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `from_agent_name` string, nullable — Name of the callable agent this message came from. Absent when received from the primary agent. - `content` BetaManagedAgentsUserContentBlock[], required — Message content blocks. - union — Content block in a user message. Can be `text`, `image`, or `document`. - object — Regular text content. - `type` 'text', required - `text` string, required — The text content. - object — Image content specified directly as base64 data or as a reference via a URL. - `type` 'image', required - `source` union, required — Union type for image source variants. - object — Base64-encoded image data. - … - object — Image referenced by URL. - … - object — Image referenced by file ID. - … - object — Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type` 'document', required - `source` union, required — Union type for document source variants. - object — Base64-encoded document data. - … - object — Plain text document content. - … - object — Document referenced by URL. - … - object — Document referenced by file ID. - … - `title` string, nullable — The title of the document. - `context` string, nullable — Additional context about the document for the model. - `from_session_thread_id` string, required — Public `sthr_` ID of the thread that sent the message. - object — Observability event emitted to the sender's output stream when an agent-to-agent message is sent. - `type` 'agent.thread_message_sent', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `to_agent_name` string, nullable — Name of the callable agent this message was sent to. Absent when sent to the primary agent. - `content` BetaManagedAgentsUserContentBlock[], required — Message content blocks. - union — Content block in a user message. Can be `text`, `image`, or `document`. - object — Regular text content. - `type` 'text', required - `text` string, required — The text content. - object — Image content specified directly as base64 data or as a reference via a URL. - `type` 'image', required - `source` union, required — Union type for image source variants. - object — Base64-encoded image data. - … - object — Image referenced by URL. - … - object — Image referenced by file ID. - … - object — Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type` 'document', required - `source` union, required — Union type for document source variants. - object — Base64-encoded document data. - … - object — Plain text document content. - … - object — Document referenced by URL. - … - object — Document referenced by file ID. - … - `title` string, nullable — The title of the document. - `context` string, nullable — Additional context about the document for the model. - `to_session_thread_id` string, required — Public `sthr_` ID of the thread the message was sent to. - object — Indicates that context compaction (summarization) occurred during the session. - `type` 'agent.thread_context_compacted', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — An error event indicating a problem occurred during session execution. - `type` 'session.error', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `error` union, required - object — An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone. - `type` 'unknown_error', required - `message` string, required — Human-readable error description. - `retry_status` union, required — What the client should do next in response to this error. - object — The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out. - `type` 'retrying', required - object — This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt. - `type` 'exhausted', required - object — The session encountered a terminal error and will transition to `terminated` state. - `type` 'terminal', required - object — The model is currently overloaded. Emitted after automatic retries are exhausted. - `type` 'model_overloaded_error', required - `message` string, required — Human-readable error description. - `retry_status` union, required — What the client should do next in response to this error. - object — The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out. - `type` 'retrying', required - object — This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt. - `type` 'exhausted', required - object — The session encountered a terminal error and will transition to `terminated` state. - `type` 'terminal', required - object — The model request was rate-limited. - `type` 'model_rate_limited_error', required - `message` string, required — Human-readable error description. - `retry_status` union, required — What the client should do next in response to this error. - object — The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out. - `type` 'retrying', required - object — This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt. - `type` 'exhausted', required - object — The session encountered a terminal error and will transition to `terminated` state. - `type` 'terminal', required - object — A model request failed for a reason other than overload or rate-limiting. - `type` 'model_request_failed_error', required - `message` string, required — Human-readable error description. - `retry_status` union, required — What the client should do next in response to this error. - object — The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out. - `type` 'retrying', required - object — This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt. - `type` 'exhausted', required - object — The session encountered a terminal error and will transition to `terminated` state. - `type` 'terminal', required - object — Failed to connect to an MCP server. - `type` 'mcp_connection_failed_error', required - `message` string, required — Human-readable error description. - `retry_status` union, required — What the client should do next in response to this error. - object — The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out. - `type` 'retrying', required - object — This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt. - `type` 'exhausted', required - object — The session encountered a terminal error and will transition to `terminated` state. - `type` 'terminal', required - `mcp_server_name` string, required — Name of the MCP server that failed to connect. - object — Authentication to an MCP server failed. - `type` 'mcp_authentication_failed_error', required - `message` string, required — Human-readable error description. - `retry_status` union, required — What the client should do next in response to this error. - object — The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out. - `type` 'retrying', required - object — This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt. - `type` 'exhausted', required - object — The session encountered a terminal error and will transition to `terminated` state. - `type` 'terminal', required - `mcp_server_name` string, required — Name of the MCP server that failed authentication. - object — The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state. - `type` 'billing_error', required - `message` string, required — Human-readable error description. - `retry_status` union, required — What the client should do next in response to this error. - object — The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out. - `type` 'retrying', required - object — This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt. - `type` 'exhausted', required - object — The session encountered a terminal error and will transition to `terminated` state. - `type` 'terminal', required - object — Indicates the session is recovering from an error state and is rescheduled for execution. - `type` 'session.status_rescheduled', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — Indicates the session is actively running and the agent is working. - `type` 'session.status_running', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — Indicates the agent has paused and is awaiting user input. - `type` 'session.status_idle', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `stop_reason` union, required - object — The agent completed its turn naturally and is ready for the next user message. - `type` 'end_turn', required - object — The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running. - `type` 'requires_action', required - `event_ids` string[], required — The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder. - object — The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`). - `type` 'retries_exhausted', required - object — Indicates the session has terminated, either due to an error or completion. - `type` 'session.status_terminated', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation. - `type` 'session.thread_created', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `agent_name` string, required — Name of the callable agent the thread runs. - `session_thread_id` string, required — Public `sthr_` ID of the newly created thread. - object — Emitted when an outcome evaluation cycle begins. - `type` 'span.outcome_evaluation_start', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `iteration` integer, required — 0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc. - `outcome_id` string, required — The `outc_` ID of the outcome being evaluated. - object — Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow. - `type` 'span.outcome_evaluation_end', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `outcome_evaluation_start_id` string, required — The id of the corresponding `span.outcome_evaluation_start` event. - `iteration` integer, required — 0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`. - `result` string, required — Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress. - `explanation` string, required — Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why. - `usage` BetaManagedAgentsSpanModelUsage, required — Token usage for a single model request. - `input_tokens` integer, required — Input tokens consumed by this request. - `output_tokens` integer, required — Output tokens generated by this request. - `cache_creation_input_tokens` integer, required — Tokens used to create prompt cache in this request. - `cache_read_input_tokens` integer, required — Tokens read from prompt cache in this request. - `speed` 'standard' | 'fast' — Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time. - `outcome_id` string, required — The `outc_` ID of the outcome being evaluated. - object — Emitted when a model request is initiated by the agent. - `type` 'span.model_request_start', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — Emitted when a model request completes. - `type` 'span.model_request_end', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `is_error` boolean, nullable, required — Whether the model request resulted in an error. - `model_usage` BetaManagedAgentsSpanModelUsage, required — Token usage for a single model request. - `input_tokens` integer, required — Input tokens consumed by this request. - `output_tokens` integer, required — Output tokens generated by this request. - `cache_creation_input_tokens` integer, required — Tokens used to create prompt cache in this request. - `cache_read_input_tokens` integer, required — Tokens read from prompt cache in this request. - `speed` 'standard' | 'fast' — Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time. - `model_request_start_id` string, required — The id of the corresponding `span.model_request_start` event. - object — Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events. - `type` 'span.outcome_evaluation_ongoing', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `iteration` integer, required — 0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`. - `outcome_id` string, required — The `outc_` ID of the outcome being evaluated. - 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', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `outcome_id` string, required — Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list. - `description` string, required — What the agent should produce. Copied from the input event. - `max_iterations` integer, nullable, required — Evaluate-then-revise cycles before giving up. Default 3, max 20. - `rubric` union, required — Rubric for grading the quality of an outcome. - BetaManagedAgentsFileRubric — Rubric referenced by a file uploaded via the Files API. - `type` 'file', required - `file_id` string, required — ID of the rubric file. - BetaManagedAgentsTextRubric — Rubric content provided inline as text. - `type` 'text', required - `content` string, required — Rubric content. Plain text or markdown — the grader treats it as freeform text. - object — Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session. - `type` 'session.deleted', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - object — A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads. - `type` 'session.thread_status_running', required - `id` string, required — Unique identifier for this event. - `session_thread_id` string, required — Public sthr_ ID of the thread that started running. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `agent_name` string, required — Name of the agent the thread runs. - object — A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads. - `type` 'session.thread_status_idle', required - `id` string, required — Unique identifier for this event. - `session_thread_id` string, required — Public sthr_ ID of the thread that went idle. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `agent_name` string, required — Name of the agent the thread runs. - `stop_reason` union, required - object — The agent completed its turn naturally and is ready for the next user message. - `type` 'end_turn', required - object — The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running. - `type` 'requires_action', required - `event_ids` string[], required — The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder. - object — The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`). - `type` 'retries_exhausted', required - object — A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads. - `type` 'session.thread_status_terminated', required - `id` string, required — Unique identifier for this event. - `session_thread_id` string, required — Public sthr_ ID of the thread that terminated. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `agent_name` string, required — Name of the agent the thread runs. - 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', required - `id` string, required — Unique identifier for this event. - `tool_use_id` string, required — 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#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. - `content` BetaManagedAgentsToolResultContentBlock[] — The result content returned by the tool. - union — Content block in a tool result. Can be `text`, `image`, `document`, or `search_result`. - object — Regular text content. - `type` 'text', required - `text` string, required — The text content. - object — Image content specified directly as base64 data or as a reference via a URL. - `type` 'image', required - `source` union, required — Union type for image source variants. - object — Base64-encoded image data. - … - object — Image referenced by URL. - … - object — Image referenced by file ID. - … - object — Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type` 'document', required - `source` union, required — Union type for document source variants. - object — Base64-encoded document data. - … - object — Plain text document content. - … - object — Document referenced by URL. - … - object — Document referenced by file ID. - … - `title` string, nullable — The title of the document. - `context` string, nullable — Additional context about the document for the model. - object — A block containing a web search result. - `type` 'search_result', required - `source` string, required — The URL source of the search result. - `title` string, required — The title of the search result. - `content` BetaManagedAgentsSearchResultContent[], required — Array of text content blocks from the search result. - `type` 'text', required - `text` string, required — The text content. - `citations` BetaManagedAgentsSearchResultCitations, required — Citation settings for a search result. - `enabled` boolean, required — Whether citations are enabled for this search result. - `is_error` boolean, nullable — Whether the tool execution resulted in an error. - `processed_at` string, date-time — A timestamp in RFC 3339 format - `session_thread_id` string, nullable — Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`. - object — A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads. - `type` 'session.thread_status_rescheduled', required - `id` string, required — Unique identifier for this event. - `session_thread_id` string, required — Public sthr_ ID of the thread that is retrying. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `agent_name` string, required — Name of the agent the thread runs. - object — Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn. - `type` 'session.updated', required - `id` string, required — Unique identifier for this event. - `processed_at` string, date-time, required — A timestamp in RFC 3339 format - `title` string, nullable — The session's new title. Present only when the update changed it. - `metadata` object — The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty. - `agent` BetaManagedAgentsSessionAgent — Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time. - `type` 'agent', required - `id` string, required - `version` integer, required - `name` string, required - `description` string, nullable, required - `model` BetaManagedAgentsModelConfig, required — Model identifier and configuration. - `id` union, required — The model that will power your agent.\n\nSee [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options. - string - 'claude-opus-4-7' — Frontier intelligence for long-running agents and coding - 'claude-opus-4-6' — Most intelligent model for building agents and coding - 'claude-sonnet-4-6' — Best combination of speed and intelligence - 'claude-haiku-4-5' — Fastest model with near-frontier intelligence - 'claude-haiku-4-5-20251001' — Fastest model with near-frontier intelligence - 'claude-opus-4-5' — Premium model combining maximum intelligence with practical performance - 'claude-opus-4-5-20251101' — Premium model combining maximum intelligence with practical performance - 'claude-sonnet-4-5' — High-performance model for agents and coding - 'claude-sonnet-4-5-20250929' — High-performance model for agents and coding - `speed` 'standard' | 'fast' — Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time. - `system` string, nullable, required - `tools` BetaManagedAgentsAgentTool[], required - union — Union type for tool configurations returned in API responses. - object - `type` 'agent_toolset_20260401', required - `default_config` BetaManagedAgentsAgentToolsetDefaultConfig, required — Resolved default configuration for agent tools. - … - `configs` BetaManagedAgentsAgentToolConfig[], required - … - object - `type` 'mcp_toolset', required - `mcp_server_name` string, required - `default_config` BetaManagedAgentsMCPToolsetDefaultConfig, required — Resolved default configuration for all tools from an MCP server. - … - `configs` BetaManagedAgentsMCPToolConfig[], required - … - object — A custom tool as returned in API responses. - `type` 'custom', required - `name` string, required - `description` string, required - `input_schema` BetaManagedAgentsCustomToolInputSchema, required — JSON Schema for custom tool input parameters. - … - `mcp_servers` BetaManagedAgentsMCPServer[], required - `type` 'url', required - `name` string, required - `url` string, required - `skills` BetaManagedAgentsSkill[], required - union — Resolved skill as returned in API responses. - BetaManagedAgentsAnthropicSkill — A resolved Anthropic-managed skill. - `type` 'anthropic', required - `skill_id` string, required - `version` string, required - BetaManagedAgentsCustomSkill — A resolved user-created custom skill. - `type` 'custom', required - `skill_id` string, required - `version` string, required - `multiagent` BetaManagedAgentsSessionMultiagent, required — Resolved coordinator topology with full agent definitions for each roster member. - `type` 'coordinator', required - `agents` BetaManagedAgentsSessionThreadAgent[], required — Full `agent` definitions the coordinator may spawn as session threads. - `type` 'agent', required - `id` string, required - `version` integer, required - `name` string, required - `description` string, nullable, required - `model` BetaManagedAgentsModelConfig, required — Model identifier and configuration. - `id` union, required — The model that will power your agent.\n\nSee [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options. - … - `speed` 'standard' | 'fast' — Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time. - `system` string, nullable, required - `tools` BetaManagedAgentsAgentTool[], required - union — Union type for tool configurations returned in API responses. - … - `mcp_servers` BetaManagedAgentsMCPServer[], required - `type` 'url', required - `name` string, required - `url` string, required - `skills` BetaManagedAgentsSkill[], required - union — Resolved skill as returned in API responses. - … ## Other responses - `400` — Invalid argument - The client specified an invalid argument - `401` — Unauthenticated - The request does not have valid authentication credentials - `403` — Permission denied - The caller does not have permission to execute the specified operation - `404` — Not found - Some requested entity was not found - `408` — Deadline exceeded - The deadline expired before the operation could complete - `409` — Aborted - The operation was aborted due to concurrency issue - `412` — Failed precondition - Operation was rejected because the system is not in required state - `413` — Out of range - Operation was attempted past the valid range - `429` — Resource exhausted - Some resource has been exhausted (rate limiting) - `431` — Request header fields too large - Request metadata was too large - `499` — Cancelled - The operation was cancelled by the client - `500` — Internal - Internal server error - `501` — Unimplemented - The operation is not implemented or supported - `503` — Unavailable - The service is currently unavailable - `504` — Deadline exceeded - Upstream service did not respond in time ## Changes - **2026-05-19** `40e330aba8bc` — 1 breaking, 1 info - added `#/components/schemas/BetaManagedAgentsUserToolResultEvent, #/components/schemas/BetaManagedAgentsSessionUpdatedEvent` to the response body `oneOf` list for the response status `200` - added `user.tool_result, session.updated` mapping keys to the response discriminator for the response status `200` - **2026-05-13** `88ef81f4f457` — 3 breaking - removed the required property `oneOf[#/components/schemas/BetaManagedAgentsAgentMcpToolResultEvent]/content/items/oneOf[#/components/schemas/BetaManagedAgentsSearchResultBlock]/tool_use_id` from the response with the `200` status - removed the required property `oneOf[#/components/schemas/BetaManagedAgentsAgentToolResultEvent]/content/items/oneOf[#/components/schemas/BetaManagedAgentsSearchResultBlock]/tool_use_id` from the response with the `200` status - removed the required property `oneOf[#/components/schemas/BetaManagedAgentsUserCustomToolResultEvent]/content/items/oneOf[#/components/schemas/BetaManagedAgentsSearchResultBlock]/tool_use_id` from the response with the `200` status - …earlier changes not shown [Full history](https://skmtc.dev/anthropics/apis/anthropic-api/changes/v1/sessions/:session_id/events/stream?beta=true/get.md) --- [API](https://skmtc.dev/anthropics/apis/anthropic-api.md) · [All operations](https://skmtc.dev/anthropics/apis/anthropic-api/llms.txt) · [OpenAPI document](https://skmtc.dev/anthropics/apis/anthropic-api/revisions/478045ff0f4f?raw)