Send Events

client.beta.sessions.events.send(, , ?): BetaManagedAgentsSendSessionEvents

POST/v1/sessions/{session_id}/events

Send Events

Parameters

sessionID: string

params: EventSendParams { events, betas }

events: Array<BetaManagedAgentsEventParams>

Body param: Events to send to the session.

One of the following:

BetaManagedAgentsUserMessageEventParams { content, type }

Parameters for sending a user message to the session.

BetaManagedAgentsUserInterruptEventParams { type, session_thread_id }

Parameters for sending an interrupt to pause the agent.

type: "user.interrupt"

session_thread_id?: string | 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 { result, tool_use_id, type, deny_message }

Parameters for confirming or denying a tool execution request.

result: "allow" | "deny"

UserToolConfirmationResult enum

One of the following:

"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 stop_reason.event_ids field.

minLength1

maxLength128

type: "user.tool_confirmation"

deny_message?: string | null

Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

maxLength10000

BetaManagedAgentsUserCustomToolResultEventParams { custom_tool_use_id, type, content, is_error }

Parameters for providing the result of a custom tool execution.

BetaManagedAgentsUserDefineOutcomeEventParams { description, rubric, type, max_iterations }

Parameters for defining an outcome the agent should work toward. The agent begins work on receipt.

BetaManagedAgentsUserToolResultEventParams { tool_use_id, type, content, is_error }

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.

BetaManagedAgentsSystemMessageEventParams { content, type }

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.

content: Array<BetaManagedAgentsSystemContentBlock { text, type }>

System content blocks to append. Text-only.

text: string

The text content.

minLength1

type: "text"

type: "system.message"

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

BetaManagedAgentsSendSessionEvents { data }

Events that were successfully sent to the session.

Send 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 betaManagedAgentsSendSessionEvents = await client.beta.sessions.events.send(
  "sesn_011CZkZAtmR3yMPDzynEDxu7",
  {
    events: [
      { content: [{ text: "Where is my order #1234?", type: "text" }], type: "user.message" }
    ]
  }
);

console.log(betaManagedAgentsSendSessionEvents.data);

{
  "data": [
    {
      "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
      "content": [
        {
          "text": "Where is my order #1234?",
          "type": "text"
        }
      ],
      "type": "user.message",
      "processed_at": "2026-03-15T10:00:00Z"
    }
  ]
}

Returns Examples

{
  "data": [
    {
      "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
      "content": [
        {
          "text": "Where is my order #1234?",
          "type": "text"
        }
      ],
      "type": "user.message",
      "processed_at": "2026-03-15T10:00:00Z"
    }
  ]
}