Send Events

BetaManagedAgentsSendSessionEvents Beta.Sessions.Events.Send(parameters, cancellationToken = default)

POST/v1/sessions/{session_id}/events

Send Events

Parameters

EventSendParams parameters

required string sessionID⁠Path

required IReadOnlyList<BetaManagedAgentsEventParams> events

Events to send to the session.

class BetaManagedAgentsUserMessageEventParams { Type = "user.message"; Content; }

Parameters for sending a user message to the session.

class BetaManagedAgentsUserInterruptEventParams { Type = "user.interrupt"; SessionThreadID; }

Parameters for sending an interrupt to pause the agent.

JsonElement Type = "user.interrupt"

string? SessionThreadID

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.

class BetaManagedAgentsUserToolConfirmationEventParams { Type = "user.tool_confirmation"; Result; ToolUseID; DenyMessage; }

Parameters for confirming or denying a tool execution request.

JsonElement Type = "user.tool_confirmation"

required Result Result

The confirmation result: 'allow' or 'deny'.

One of the following:

Allow("allow")

Deny("deny")

required string ToolUseID

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

string? DenyMessage

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

maxLength10000

class BetaManagedAgentsUserCustomToolResultEventParams { Type = "user.custom_tool_result"; CustomToolUseID; Content; IsError; }

Parameters for providing the result of a custom tool execution.

class BetaManagedAgentsUserDefineOutcomeEventParams { Type = "user.define_outcome"; Description; Rubric; MaxIterations; }

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

class BetaManagedAgentsUserToolResultEventParams { Type = "user.tool_result"; ToolUseID; Content; IsError; }

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.

class BetaManagedAgentsSystemMessageEventParams { Type = "system.message"; Content; }

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.

JsonElement Type = "system.message"

required IReadOnlyList<BetaManagedAgentsSystemContentBlock> Content

System content blocks to append. Text-only.

JsonElement Type = "text"

required string Text

The text content.

minLength1

IReadOnlyList<AnthropicBeta> betas⁠Header

This endpoint is in beta: requests must send managed-agents-2026-04-01 in this header.

MessageBatches2024_09_24("message-batches-2024-09-24")

PromptCaching2024_07_31("prompt-caching-2024-07-31")

ComputerUse2024_10_22("computer-use-2024-10-22")

ComputerUse2025_01_24("computer-use-2025-01-24")

Pdfs2024_09_25("pdfs-2024-09-25")

TokenCounting2024_11_01("token-counting-2024-11-01")

TokenEfficientTools2025_02_19("token-efficient-tools-2025-02-19")

Output128k2025_02_19("output-128k-2025-02-19")

FilesApi2025_04_14("files-api-2025-04-14")

McpClient2025_04_04("mcp-client-2025-04-04")

McpClient2025_11_20("mcp-client-2025-11-20")

DevFullThinking2025_05_14("dev-full-thinking-2025-05-14")

InterleavedThinking2025_05_14("interleaved-thinking-2025-05-14")

CodeExecution2025_05_22("code-execution-2025-05-22")

ExtendedCacheTtl2025_04_11("extended-cache-ttl-2025-04-11")

Context1m2025_08_07("context-1m-2025-08-07")

ContextManagement2025_06_27("context-management-2025-06-27")

ModelContextWindowExceeded2025_08_26("model-context-window-exceeded-2025-08-26")

Skills2025_10_02("skills-2025-10-02")

FastMode2026_02_01("fast-mode-2026-02-01")

Output300k2026_03_24("output-300k-2026-03-24")

UserProfiles2026_03_24("user-profiles-2026-03-24")

UserProfiles2026_08_18("user-profiles-2026-08-18")

UserProfiles2026_09_04("user-profiles-2026-09-04")

AdvisorTool2026_03_01("advisor-tool-2026-03-01")

ManagedAgents2026_04_01("managed-agents-2026-04-01")

CacheDiagnosis2026_04_07("cache-diagnosis-2026-04-07")

Dreaming2026_04_21("dreaming-2026-04-21")

ThinkingTokenCount2026_05_13("thinking-token-count-2026-05-13")

ServerSideFallback2026_06_01("server-side-fallback-2026-06-01")

ServerSideFallback2026_07_01("server-side-fallback-2026-07-01")

FallbackCredit2026_06_01("fallback-credit-2026-06-01")

FallbackCredit2026_07_01("fallback-credit-2026-07-01")

AgentMemory2026_07_22("agent-memory-2026-07-22")

MidConversationToolChanges2026_07_01("mid-conversation-tool-changes-2026-07-01")

Compact2026_01_12("compact-2026-01-12")

ComputerUse2025_11_24("computer-use-2025-11-24")

McpTunnels2026_06_22("mcp-tunnels-2026-06-22")

StructuredOutputs2025_11_13("structured-outputs-2025-11-13")

TaskBudgets2026_03_13("task-budgets-2026-03-13")

ThinkingDisplayUpdates2026_08_18("thinking-display-updates-2026-08-18")

CEUserManagement2026_07_13("ce-user-management-2026-07-13")

MidConversationOutputConfig2026_07_01("mid-conversation-output-config-2026-07-01")

ThinkingBindingControls2026_08_01("thinking-binding-controls-2026-08-01")

MidConversationSystemClearAt2026_08_21("mid-conversation-system-clear-at-2026-08-21")

Compact2026_09_04("compact-2026-09-04")

InlineTools2026_09_15("inline-tools-2026-09-15")

McpClient2026_09_15("mcp-client-2026-09-15")

CEPlugins2026_09_01("ce-plugins-2026-09-01")

SpendLimitReads2026_09_26("spend-limit-reads-2026-09-26")

TelemetryDestinations2026_08_11("telemetry-destinations-2026-08-11")

Webhooks2026_10_07("webhooks-2026-10-07")

MessageThreads2026_08_12("message-threads-2026-08-12")

AnalyticsUsageCost2026_08_24("analytics-usage-cost-2026-08-24")

ExperimentalClaudeTag2026_10_21("experimental-claude-tag-2026-10-21")

string workspaceID⁠Header

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.

Returns

class BetaManagedAgentsSendSessionEvents { Data; }

Events that were successfully sent to the session.

Send Events

using System;
using Anthropic.Models.Beta.Sessions.Events;

EventSendParams parameters = new()
{
    SessionID = "sesn_011CZkZAtmR3yMPDzynEDxu7",
    Events =
    [
        new BetaManagedAgentsUserMessageEventParams(

            [
                new BetaManagedAgentsTextBlock("Where is my order #1234?")
            ]
        ),
    ],
};

var betaManagedAgentsSendSessionEvents = await client.Beta.Sessions.Events.Send(parameters);

Console.WriteLine(betaManagedAgentsSendSessionEvents);

Response 200

{
  "data": [
    {
      "id": "sevt_011CZkZGPp1iBcp4kaQSihUm",
      "content": [
        {
          "text": "Where is my order #1234?",
          "type": "text"
        }
      ],
      "type": "user.message",
      "processed_at": "2026-03-15T10:00:00Z"
    }
  ]
}

Returns Examples

Response 200

{
  "data": [
    {
      "id": "sevt_011CZkZGPp1iBcp4kaQSihUm",
      "content": [
        {
          "text": "Where is my order #1234?",
          "type": "text"
        }
      ],
      "type": "user.message",
      "processed_at": "2026-03-15T10:00:00Z"
    }
  ]
}