Claude Platform Docs

Stream Events

client.beta.sessions.events.stream(stringsessionID, EventStreamParamsparams?, RequestOptionsoptions?): BetaManagedAgentsStreamSessionEvents | Stream<BetaManagedAgentsStreamSessionEvents>
GET/v1/sessions/{session_id}/events/stream

Stream Events

Parameters
sessionID: string
params: EventStreamParams { event_deltas, betas }
event_deltas?: Array<BetaManagedAgentsDeltaType>

Query param: 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.

One of the following:
"agent.message"
"agent.thinking"
betas?: Array<AnthropicBeta>

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

One of the following:
(string & {})
"message-batches-2024-09-24" | "prompt-caching-2024-07-31" | "computer-use-2024-10-22" | 38 more
"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"
"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"
Returns
BetaManagedAgentsStreamSessionEvents = BetaManagedAgentsUserMessageEvent { id, content, type, processed_at } | BetaManagedAgentsUserInterruptEvent { id, type, processed_at, session_thread_id } | BetaManagedAgentsUserToolConfirmationEvent { id, result, tool_use_id, 4 more } | 34 more

Server-sent event in the session stream.

One of the following:
BetaManagedAgentsStreamSessionEvents = BetaManagedAgentsUserMessageEvent { id, content, type, processed_at } | BetaManagedAgentsUserInterruptEvent { id, type, processed_at, session_thread_id } | BetaManagedAgentsUserToolConfirmationEvent { id, result, tool_use_id, 4 more } | 34 more

Server-sent event in the session stream.

One of the following:

Stream Events

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic({
  apiKey: process.env["ANTHROPIC_API_KEY"] // This is the default and can be omitted
});

const betaManagedAgentsStreamSessionEvents = await client.beta.sessions.events.stream(
  "sesn_011CZkZAtmR3yMPDzynEDxu7"
);

console.log(betaManagedAgentsStreamSessionEvents);
{
  "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
  "content": [
    {
      "text": "Where is my order #1234?",
      "type": "text"
    }
  ],
  "type": "user.message",
  "processed_at": "2026-03-15T10:00:00Z"
}
Returns Examples
{
  "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
  "content": [
    {
      "text": "Where is my order #1234?",
      "type": "text"
    }
  ],
  "type": "user.message",
  "processed_at": "2026-03-15T10:00:00Z"
}