订阅线程事件

先调用「创建会话」，用返回的会话 ID 替换示例 ID。

GET /agent/v1/sessions/{session_id}/threads/{thread_id}/stream◐ 部分支持

请求参数

session_idstring必填
path: Session id (sesn_...), as returned by sessions.create or sessions.list. The same id is also accepted as the session_id query parameter on resource and thread calls, where it must equal the path value.
thread_idstring必填
path: Execution thread id (sthr_...), as listed by sessions.threads.list; the primary thread id equals the session's own thread. Unknown or foreign ids return 404.
session_idstring必填
query: Session id (sesn_...), as returned by sessions.create or sessions.list. The same id is also accepted as the session_id query parameter on resource and thread calls, where it must equal the path value.
event_deltasarray可选
query: When set, this connection also receives streaming deltas (`event_start`, `event_delta`) while an event is being produced, before the event itself arrives. Deltas are best-effort; when the final event is produced it carries the complete content. A model request that ends early (an error or interrupt) produces no final event — its terminal `span.model_request_end` closes the preview. Accepts one or more event types to preview and may be repeated: `agent.message` streams `content_delta` fragments; `agent.thinking` is start-only — a signal that the agent has begun extended thinking, concluded by the `agent.thinking` event itself. Only previews of the requested event types are sent.

200

订阅所选线程自己的实时事件流。复用会话 SSE 实现；/agent 接口支持同址只读 WebSocket。主会话流同时包含子线程创建、状态和消息事件，子线程审批带 session_thread_id 上浮；确认或中断携带该字段时路由到所属子线程。

错误按 Anthropic 错误格式返回（type / message / request_id），参见错误码

响应

HTTP 200

Server-sent events

text/event-stream — chunk / 事件对象

名称	类型	说明
id	string	Identifier of the object, as returned by the API; pass it in the path of follow-up calls on the same resource.
event	string	Server-Sent Events event name of this frame. / Always `user.message`. SSE event name of this frame; its data is a user.message payload. A message from the user to the agent, with content blocks. / Always `user.interrupt`. SSE event name of this frame; its data is a user.interrupt payload. The user interrupted the running turn. / Always `agent.message`. SSE event name of this frame; its data is a agent.message payload. A message from the agent, with text content blocks. / Always `agent.thinking`. SSE event name of this frame; its data is a agent.thinking payload. The agent's thinking text for a step. / Always `session.status_running`. SSE event name of this frame; its data is a session.status_running payload. The session started running a turn. / Always `session.status_rescheduled`. SSE event name of this frame; its data is a session.status_rescheduled payload. The session will retry after a recoverable error. / Always `session.status_idle`. SSE event name of this frame; its data is a session.status_idle payload. The session stopped running; stop_reason says why. / Always `session.status_terminated`. SSE event name of this frame; its data is a session.status_terminated payload. The session ended and accepts no more work. / Always `agent.thread_context_compacted`. SSE event name of this frame; its data is a agent.thread_context_compacted payload. The thread's context was compacted into a summary. / Always `agent.thread_context_reset`. SSE event name of this frame; its data is a agent.thread_context_reset payload. Content was removed from the model's context after a content-safety refusal. / Always `session.updated`. SSE event name of this frame; its data is a session.updated payload. The session's model, title, metadata, agent or budget changed. / Always `session.error`. SSE event name of this frame; its data is a session.error payload. The session hit an error. / Always `session.usage`. SSE event name of this frame; its data is a session.usage payload. Cumulative usage of the session. / Always `span.model_request_start`. SSE event name of this frame; its data is a span.model_request_start payload. A model request started. / Always `span.model_request_end`. SSE event name of this frame; its data is a span.model_request_end payload. A model request ended, with its usage. / Always `agent.tool_use`. SSE event name of this frame; its data is a agent.tool_use payload. The agent called a tool. / Always `agent.tool_result`. SSE event name of this frame; its data is a agent.tool_result payload. The result of a tool call. / Always `agent.mcp_tool_use`. SSE event name of this frame; its data is a agent.mcp_tool_use payload. The agent called an MCP tool. / Always `agent.mcp_tool_result`. SSE event name of this frame; its data is a agent.mcp_tool_result payload. The result of an MCP tool call. / Always `user.tool_confirmation`. SSE event name of this frame; its data is a user.tool_confirmation payload. The user's decision to allow or deny a tool call that waits for approval. / Always `session.thread_created`. SSE event name of this frame; its data is a session.thread_created payload. A child thread was started. / Always `session.thread_status_running`. SSE event name of this frame; its data is a session.thread_status_running payload. A thread started running. / Always `session.thread_status_idle`. SSE event name of this frame; its data is a session.thread_status_idle payload. A thread stopped running; stop_reason says why. / Always `session.thread_status_rescheduled`. SSE event name of this frame; its data is a session.thread_status_rescheduled payload. A thread will retry after a recoverable error. / Always `session.thread_status_terminated`. SSE event name of this frame; its data is a session.thread_status_terminated payload. A thread ended. / Always `agent.thread_message_sent`. SSE event name of this frame; its data is a agent.thread_message_sent payload. The agent sent a message to another thread. / Always `agent.thread_message_received`. SSE event name of this frame; its data is a agent.thread_message_received payload. The agent received a message from another thread. / Always `user.withdraw`. SSE event name of this frame; its data is a user.withdraw payload. A queued user.message was withdrawn before it ran. / Always `user.steer`. SSE event name of this frame; its data is a user.steer payload. Receipt that a queued user.message was injected into the running turn. / Always `system.notification`. SSE event name of this frame; its data is a system.notification payload. Background work woke the session with a notification. / Always `session.forked`. SSE event name of this frame; its data is a session.forked payload. The session was created by forking another session. / Always `session.goal_changed`. SSE event name of this frame; its data is a session.goal_changed payload. The session's goal was set, changed status, accounted usage or was cleared. / Always `session.goal_verification`. SSE event name of this frame; its data is a session.goal_verification payload. One completion check of the session's goal started or ended. / Always `event_start`. SSE event name of this frame; its data is a event_start payload. Preview that an event of the requested delta types has started. / Always `event_delta`. SSE event name of this frame; its data is a event_delta payload. Incremental fragment of the event being produced. / Always `ping`. SSE event name of this frame; its data is a ping payload. Keep-alive frame; carries no data. / Always `error`. SSE event name of this frame; its data is a error payload. A stream error.
data	object	Decoded JSON payload of this frame; its shape is selected by the event name. / Praxis extension (AskUserQuestion, own face only): the confirmation of an AskUserQuestion call, with the answers it carried. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Praxis extension (goal mode, own face only): the session's goal was set, moved to another status, accounted usage or was cleared. `goal` is the goal after the change, `previous_goal` the one before; each is null when there was none. / Praxis extension (goal mode, own face only): one completion check of the goal. A `started` event opens it; `completed`, `failed_closed` or `cancelled` closes it. Events of one check share `verification_id`. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name. / Decoded JSON payload of this frame; its shape is selected by the event name.
data.id	string	Unique identifier for this event. / Text of the block. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Event id, unique within the session. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Text of the block. / Event id, unique within the session. Use it to refer to this event, for example in user.tool_confirmation or user.steer. / Text of the block. / Event id, unique within the session. Use it to refer to this event, for example in user.tool_confirmation or user.steer. / Event id, unique within the session. / Event id, unique within the session. Use it to refer to this event, for example in user.tool_confirmation or user.steer. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Text of the block. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Event id, unique within the session. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Unique identifier for this event. / Text of the block. / Event id, unique within the session. Use it to refer to this event, for example in user.tool_confirmation or user.steer. / Text of the block. / Event id, unique within the session. Use it to refer to this event, for example in user.tool_confirmation or user.steer. / Event id, unique within the session. / Event id, unique within the session. Use it to refer to this event, for example in user.tool_confirmation or user.steer.
data.content	array<object>	Array of content blocks comprising the user message. / Array of text blocks comprising the agent response. / Content blocks of the event, in order. / The result content returned by the tool. / The result content returned by the tool. / Message content blocks. / Message content blocks. / Array of content blocks comprising the user message. / Array of text blocks comprising the agent response. / Content blocks of the event, in order. / The result content returned by the tool. / The result content returned by the tool. / Message content blocks. / Message content blocks.
data.type	string	Always `user.message`. A message from the user to the agent, with content blocks. / Always `user.interrupt`. The user interrupted the running turn. / Always `agent.message`. A message from the agent, with text content blocks. / Always `agent.thinking`. The agent's thinking text for a step. / Always `session.status_running`. The session started running a turn. / Always `session.status_rescheduled`. The session will retry after a recoverable error. / Always `session.status_idle`. The session stopped running; stop_reason says why. / Always `session.status_terminated`. The session ended and accepts no more work. / Always `agent.thread_context_compacted`. The thread's context was compacted into a summary. / Always `agent.thread_context_reset`. Content was removed from the model's context after a content-safety refusal. / Always `session.updated`. The session's model, title, metadata, agent or budget changed. / Always `session.error`. The session hit an error. / Always `session.usage`. Cumulative usage of the session. / Always `span.model_request_start`. A model request started. / Always `span.model_request_end`. A model request ended, with its usage. / Always `agent.tool_use`. The agent called a tool. / Always `agent.tool_result`. The result of a tool call. / Always `agent.mcp_tool_use`. The agent called an MCP tool. / Always `agent.mcp_tool_result`. The result of an MCP tool call. / Always `user.tool_confirmation`. / Always `session.thread_created`. A child thread was started. / Always `session.thread_status_running`. A thread started running. / Always `session.thread_status_idle`. A thread stopped running; stop_reason says why. / Always `session.thread_status_rescheduled`. A thread will retry after a recoverable error. / Always `session.thread_status_terminated`. A thread ended. / Always `agent.thread_message_sent`. The agent sent a message to another thread. / Always `agent.thread_message_received`. The agent received a message from another thread. / Always `user.withdraw`. A queued user.message was withdrawn before it ran. / Always `user.steer`. Receipt that a queued user.message was injected into the running turn. / Always `system.notification`. Background work woke the session with a notification. / Always `session.forked`. The session was created by forking another session. / Always `session.goal_changed`. / Always `session.goal_verification`. / Always `event_start`. Preview that an event of the requested delta types has started. / Always `event_delta`. Incremental fragment of the event being produced. / Always `ping`. Keep-alive frame; carries no data. / Always `error`. A stream error. / Always `user.message`. A message from the user to the agent, with content blocks. / Always `user.interrupt`. The user interrupted the running turn. / Always `agent.message`. A message from the agent, with text content blocks. / Always `agent.thinking`. The agent's thinking text for a step. / Always `session.status_running`. The session started running a turn. / Always `session.status_rescheduled`. The session will retry after a recoverable error. / Always `session.status_idle`. The session stopped running; stop_reason says why. / Always `session.status_terminated`. The session ended and accepts no more work. / Always `agent.thread_context_compacted`. The thread's context was compacted into a summary. / Always `agent.thread_context_reset`. Content was removed from the model's context after a content-safety refusal. / Always `session.updated`. The session's model, title, metadata, agent or budget changed. / Always `session.error`. The session hit an error. / Always `session.usage`. Cumulative usage of the session. / Always `span.model_request_start`. A model request started. / Always `span.model_request_end`. A model request ended, with its usage. / Always `agent.tool_use`. The agent called a tool. / Always `agent.tool_result`. The result of a tool call. / Always `agent.mcp_tool_use`. The agent called an MCP tool. / Always `agent.mcp_tool_result`. The result of an MCP tool call. / Always `user.tool_confirmation`. / Always `session.thread_created`. A child thread was started. / Always `session.thread_status_running`. A thread started running. / Always `session.thread_status_idle`. A thread stopped running; stop_reason says why. / Always `session.thread_status_rescheduled`. A thread will retry after a recoverable error. / Always `session.thread_status_terminated`. A thread ended. / Always `agent.thread_message_sent`. The agent sent a message to another thread. / Always `agent.thread_message_received`. The agent received a message from another thread. / Always `user.withdraw`. A queued user.message was withdrawn before it ran. / Always `user.steer`. Receipt that a queued user.message was injected into the running turn. / Always `system.notification`. Background work woke the session with a notification. / Always `session.forked`. The session was created by forking another session. / Always `session.goal_changed`. / Always `session.goal_verification`. / Always `event_start`. Preview that an event of the requested delta types has started. / Always `event_delta`. Incremental fragment of the event being produced. / Always `ping`. Keep-alive frame; carries no data. / Always `error`. A stream error.
data.processed_at	null \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| null \| string \| null \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string \| string	A timestamp in RFC 3339 format / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / When the event was recorded, RFC 3339. / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / When the event was recorded, RFC 3339. / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / When the event was recorded, RFC 3339. / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / A timestamp in RFC 3339 format / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / RFC 3339 time at which the server processed the event; null while a queued input has not started running. / When the event was recorded, RFC 3339. / RFC 3339 time at which the server processed the event; null while a queued input has not started running.
data.message_id	string	UI transcript message ID. Use the last assistant message in a successfully completed turn as the fork target. / UI transcript message ID shared with this assistant's message parts. / UI transcript message ID. Use the last assistant message in a successfully completed turn as the fork target. / UI transcript message ID. Use the last assistant message in a successfully completed turn as the fork target. / UI transcript message ID shared with this assistant's message parts.
data.session_thread_id	null \| string \| string \| null \| string \| null \| string \| string \| string \| string \| string \| string \| string \| string \| null \| string \| string \| null \| string \| null \| string \| string \| string \| string \| string \| string \| string \| string	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. / Text of the block. / 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. Informational only: the server routes the matching `user.tool_confirmation` or `user.tool_result` by `tool_use_id`, so clients do not send it back. / 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. Informational only: the server routes the matching `user.tool_confirmation` by `tool_use_id`, so clients do not send it back. / Public `sthr_` ID of the newly created thread. / Public sthr_ ID of the thread that started running. / Public sthr_ ID of the thread that went idle. / Public sthr_ ID of the thread that is retrying. / Public sthr_ ID of the thread that terminated. / Text of the block. / Text of the block. / 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. / Text of the block. / 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. Informational only: the server routes the matching `user.tool_confirmation` or `user.tool_result` by `tool_use_id`, so clients do not send it back. / 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. Informational only: the server routes the matching `user.tool_confirmation` by `tool_use_id`, so clients do not send it back. / Public `sthr_` ID of the newly created thread. / Public sthr_ ID of the thread that started running. / Public sthr_ ID of the thread that went idle. / Public sthr_ ID of the thread that is retrying. / Public sthr_ ID of the thread that terminated. / Text of the block. / Text of the block.
data.stop_reason	object	Why the session stopped running, with the variant data needed to continue.
data.removed	array<object>	Content removed from the model's context by this reset.
data.category	string	Text of the block.
data.stopped	boolean	True when the run was stopped instead of retried after the reset.
data.agent	null \| object	Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.
data.budget	null \| object	A hard spend ceiling. The session stops issuing new model requests once the tracked list cost reaches `max_list_cost`.
data.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.
data.title	null \| string	The session's new title. Present only when the update changed it.
data.model	object	扩展 / Praxis extension: the changed session model, present only on /agent/v1 session.updated events. Model-only updates are omitted on /anthropic.
data.error	object	Description of the error and what the client should do next. / Error detail. / Description of the error and what the client should do next. / Error detail.
data.usage	object	Point-in-time snapshot of a session's cumulative usage.
data.is_error	null \| boolean	Whether the model request resulted in an error. / Whether the tool execution resulted in an error. / Whether the tool execution resulted in an error. / Whether the model request resulted in an error. / Whether the tool execution resulted in an error. / Whether the tool execution resulted in an error.
data.model_request_start_id	string	The id of the corresponding `span.model_request_start` event.
data.model_usage	object	Token usage for a single model request.
data.input	object	Input parameters for the tool call.
data.name	string	Name of the agent tool being used. / Name of the MCP tool being used. / Name of the agent tool being used. / Name of the MCP tool being used.
data.evaluated_permission	string	AgentEvaluatedPermission enum
data.evaluation	object	Names the resolved permission_policy that produced evaluated_permission, and under auto carries the judgement. Open union: clients must tolerate unknown variants.
data.tool_use_id	string	The id of the `agent.tool_use` event this result corresponds to. / The id of the AskUserQuestion `agent.tool_use` event this answers. / The id of the `agent.tool_use` event this result corresponds to. / The id of the AskUserQuestion `agent.tool_use` event this answers.
data.mcp_server_name	string	Name of the MCP server providing the tool.
data._meta	object	Praxis extension (MCP Apps, SEP-1865): the `ui` and `openai/ui` keys of the MCP tool definition's `_meta`, verbatim; other `_meta` keys are not exposed. When `ui.resourceUri` is a `ui://` URI, the tool has an interactive view: a client that implements MCP Apps can fetch that resource from the MCP server and render it for this call. Absent when the tool declares neither key. Clients that do not render MCP Apps ignore it. / Praxis extension (MCP Apps, SEP-1865): the MCP CallToolResult `_meta`, verbatim. Views use it for data that should not reach the model; absent when the tool returned none. / Praxis extension (MCP Apps, SEP-1865): the `ui` and `openai/ui` keys of the MCP tool definition's `_meta`, verbatim; other `_meta` keys are not exposed. When `ui.resourceUri` is a `ui://` URI, the tool has an interactive view: a client that implements MCP Apps can fetch that resource from the MCP server and render it for this call. Absent when the tool declares neither key. Clients that do not render MCP Apps ignore it. / Praxis extension (MCP Apps, SEP-1865): the MCP CallToolResult `_meta`, verbatim. Views use it for data that should not reach the model; absent when the tool returned none.
data.source	string	Praxis extension (MCP Apps, SEP-1865): `app` when the call was made by an MCP Apps view, `codemode` when a program run by the codemode tool called an MCP tool that declares a view (the event pair exists so a client can render that view; the model already has the result in the codemode tool result); absent for the model's own calls. / What caused the change. / Praxis extension (MCP Apps, SEP-1865): `app` when the call was made by an MCP Apps view, `codemode` when a program run by the codemode tool called an MCP tool that declares a view (the event pair exists so a client can render that view; the model already has the result in the codemode tool result); absent for the model's own calls. / Praxis extension (MCP Apps, SEP-1865): `app` when the call was made by an MCP Apps view, `codemode` when a program run by the codemode tool called an MCP tool that declares a view (the event pair exists so a client can render that view; the model already has the result in the codemode tool result); absent for the model's own calls. / What caused the change.
data.parent_tool_use_id	string	Praxis extension (MCP Apps, SEP-1865): present when `source` is `codemode`; the id of the codemode tool use whose program made this call. Absent otherwise.
data.mcp_tool_use_id	string	The id of the `agent.mcp_tool_use` event this result corresponds to.
data.structured_content	any	Praxis extension (MCP Apps, SEP-1865): the MCP CallToolResult `structuredContent`, verbatim JSON. MCP Apps views read it as the data to render; absent when the tool returned none.
data.result	string	Always `allow`.
data.answers	object	The user's answer to each question, keyed by the question text; empty when the questions were dismissed.
data.annotations	object	Per-question notes, keyed by the question text.
data.agent_name	string	Name of the callable agent the thread runs. / Name of the agent the thread runs. / Name of the agent the thread runs. / Name of the agent the thread runs. / Name of the agent the thread runs. / Name of the callable agent the thread runs. / Name of the agent the thread runs. / Name of the agent the thread runs. / Name of the agent the thread runs. / Name of the agent the thread runs.
data.to_session_thread_id	string	Public `sthr_` ID of the thread the message was sent to.
data.to_agent_name	null \| string	Name of the callable agent this message was sent to. Absent when sent to the primary agent.
data.from_session_thread_id	string	Public `sthr_` ID of the thread that sent the message.
data.from_agent_name	null \| string	Name of the callable agent this message came from. Absent when received from the primary agent.
data.event_id	string	Text of the block. / Id of the event this event refers to. / Text of the block. / Text of the block. / Id of the event this event refers to. / Text of the block.
data.sources	array<object>	Background work that woke the session with this notification.
data.forked_from_session_id	string	Id of the parent session this session was forked from.
data.forked_from_message_id	string	message_id of the agent message in the parent session up to which the conversation was copied.
data.action	string	What changed in the goal.
data.goal	object \| null	The goal as the change left it, or null when the session has no goal.
data.previous_goal	object \| null	The goal before the change, or null when there was none.
data.status	string	Where the check stands. Read `verification.passed` on the closing event to know whether the goal counts as done.
data.goal_id	string	The goal this check belongs to.
data.goal_iteration	integer	Which check of this goal, matching `iteration` on the goal.
data.verification_id	string	Identifier shared by every event of one check.
data.anchor_message_id	string \| null	The assistant message the check follows, or null.
data.verification	object	The verdict; absent on `started`.
data.event	object	Event name or event payload.
data.delta	object	Incremental fragment of the event being produced.