--- title: Send Events url: https://platform.claude.com/docs/en/api/java/beta/sessions/events/send --- # Send Events `BetaManagedAgentsSendSessionEvents beta().sessions().events().send(params, requestOptions = RequestOptions.none())` **POST** `/v1/sessions/{session_id}/events` Send Events ## Parameters - `EventSendParams params` - `Optional sessionId` (path parameter) - `Optional> betas` (header parameter) This endpoint is in beta: requests must send `managed-agents-2026-04-01` in this header. - `MESSAGE_BATCHES_2024_09_24("message-batches-2024-09-24")` - `PROMPT_CACHING_2024_07_31("prompt-caching-2024-07-31")` - `COMPUTER_USE_2024_10_22("computer-use-2024-10-22")` - `COMPUTER_USE_2025_01_24("computer-use-2025-01-24")` - `PDFS_2024_09_25("pdfs-2024-09-25")` - `TOKEN_COUNTING_2024_11_01("token-counting-2024-11-01")` - `TOKEN_EFFICIENT_TOOLS_2025_02_19("token-efficient-tools-2025-02-19")` - `OUTPUT_128K_2025_02_19("output-128k-2025-02-19")` - `FILES_API_2025_04_14("files-api-2025-04-14")` - `MCP_CLIENT_2025_04_04("mcp-client-2025-04-04")` - `MCP_CLIENT_2025_11_20("mcp-client-2025-11-20")` - `DEV_FULL_THINKING_2025_05_14("dev-full-thinking-2025-05-14")` - `INTERLEAVED_THINKING_2025_05_14("interleaved-thinking-2025-05-14")` - `CODE_EXECUTION_2025_05_22("code-execution-2025-05-22")` - `EXTENDED_CACHE_TTL_2025_04_11("extended-cache-ttl-2025-04-11")` - `CONTEXT_1M_2025_08_07("context-1m-2025-08-07")` - `CONTEXT_MANAGEMENT_2025_06_27("context-management-2025-06-27")` - `MODEL_CONTEXT_WINDOW_EXCEEDED_2025_08_26("model-context-window-exceeded-2025-08-26")` - `SKILLS_2025_10_02("skills-2025-10-02")` - `FAST_MODE_2026_02_01("fast-mode-2026-02-01")` - `OUTPUT_300K_2026_03_24("output-300k-2026-03-24")` - `USER_PROFILES_2026_03_24("user-profiles-2026-03-24")` - `USER_PROFILES_2026_08_18("user-profiles-2026-08-18")` - `USER_PROFILES_2026_09_04("user-profiles-2026-09-04")` - `ADVISOR_TOOL_2026_03_01("advisor-tool-2026-03-01")` - `MANAGED_AGENTS_2026_04_01("managed-agents-2026-04-01")` - `CACHE_DIAGNOSIS_2026_04_07("cache-diagnosis-2026-04-07")` - `DREAMING_2026_04_21("dreaming-2026-04-21")` - `THINKING_TOKEN_COUNT_2026_05_13("thinking-token-count-2026-05-13")` - `SERVER_SIDE_FALLBACK_2026_06_01("server-side-fallback-2026-06-01")` - `SERVER_SIDE_FALLBACK_2026_07_01("server-side-fallback-2026-07-01")` - `FALLBACK_CREDIT_2026_06_01("fallback-credit-2026-06-01")` - `FALLBACK_CREDIT_2026_07_01("fallback-credit-2026-07-01")` - `AGENT_MEMORY_2026_07_22("agent-memory-2026-07-22")` - `MID_CONVERSATION_TOOL_CHANGES_2026_07_01("mid-conversation-tool-changes-2026-07-01")` - `COMPACT_2026_01_12("compact-2026-01-12")` - `COMPUTER_USE_2025_11_24("computer-use-2025-11-24")` - `MCP_TUNNELS_2026_06_22("mcp-tunnels-2026-06-22")` - `STRUCTURED_OUTPUTS_2025_11_13("structured-outputs-2025-11-13")` - `TASK_BUDGETS_2026_03_13("task-budgets-2026-03-13")` - `THINKING_DISPLAY_UPDATES_2026_08_18("thinking-display-updates-2026-08-18")` - `CE_USER_MANAGEMENT_2026_07_13("ce-user-management-2026-07-13")` - `MID_CONVERSATION_OUTPUT_CONFIG_2026_07_01("mid-conversation-output-config-2026-07-01")` - `THINKING_BINDING_CONTROLS_2026_08_01("thinking-binding-controls-2026-08-01")` - `MID_CONVERSATION_SYSTEM_CLEAR_AT_2026_08_21("mid-conversation-system-clear-at-2026-08-21")` - `COMPACT_2026_09_04("compact-2026-09-04")` - `INLINE_TOOLS_2026_09_15("inline-tools-2026-09-15")` - `MCP_CLIENT_2026_09_15("mcp-client-2026-09-15")` - `CE_PLUGINS_2026_09_01("ce-plugins-2026-09-01")` - `SPEND_LIMIT_READS_2026_09_26("spend-limit-reads-2026-09-26")` - `TELEMETRY_DESTINATIONS_2026_08_11("telemetry-destinations-2026-08-11")` - `Optional workspaceId` (header parameter) 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. - `List events` Events to send to the `session`. - `class BetaManagedAgentsUserMessageEventParams` Parameters for sending a user message to the session. - `Type type` - `List content` Array of content blocks for the user message. - `class BetaManagedAgentsTextBlock` Regular text content. - `Type type` - `String text` The text content. minLength: 1 - `class BetaManagedAgentsImageBlock` Image content specified directly as base64 data or as a reference via a URL. - `Type type` - `Source source` The source of the image data. - `class BetaManagedAgentsBase64ImageSource` Base64-encoded image data. - `Type type` - `String data` Base64-encoded image data. minLength: 1 - `String mediaType` MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp"). minLength: 1 - `class BetaManagedAgentsUrlImageSource` Image referenced by URL. - `Type type` - `String url` URL of the image to fetch. minLength: 1 - `class BetaManagedAgentsFileImageSource` Image referenced by file ID. - `Type type` - `String fileId` ID of a previously uploaded file. minLength: 1 - `class BetaManagedAgentsDocumentBlock` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `Type type` - `Source source` The source of the document data. - `class BetaManagedAgentsBase64DocumentSource` Base64-encoded document data. - `Type type` - `String data` Base64-encoded document data. minLength: 1 - `String mediaType` MIME type of the document (e.g., "application/pdf"). minLength: 1 - `class BetaManagedAgentsPlainTextDocumentSource` Plain text document content. - `Type type` - `String data` The plain text content. minLength: 1 - `MediaType mediaType` MIME type of the text content. Must be "text/plain". - `class BetaManagedAgentsUrlDocumentSource` Document referenced by URL. - `Type type` - `String url` URL of the document to fetch. minLength: 1 - `class BetaManagedAgentsFileDocumentSource` Document referenced by file ID. - `Type type` - `String fileId` ID of a previously uploaded file. minLength: 1 - `Optional context` Additional context about the document for the model. - `Optional title` The title of the document. - `class BetaManagedAgentsRedactedBlock` Placeholder for content withheld by Anthropic model policy. - `Type type` - `class BetaManagedAgentsUserInterruptEventParams` Parameters for sending an interrupt to pause the agent. - `Type type` - `Optional 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` Parameters for confirming or denying a tool execution request. - `Type type` - `Result result` The confirmation result: 'allow' or 'deny'. - `ALLOW("allow")` - `DENY("deny")` - `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](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=java#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. minLength: 1, maxLength: 128 - `Optional denyMessage` Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'. maxLength: 10000 - `class BetaManagedAgentsUserCustomToolResultEventParams` Parameters for providing the result of a custom tool execution. - `Type type` - `String customToolUseId` The id of the `agent.custom_tool_use` event this result corresponds to. It is also listed in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=java#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. minLength: 1, maxLength: 128 - `Optional> content` The result content returned by the tool. - `class BetaManagedAgentsTextBlock` Regular text content. - `class BetaManagedAgentsImageBlock` Image content specified directly as base64 data or as a reference via a URL. - `class BetaManagedAgentsDocumentBlock` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `class BetaManagedAgentsSearchResultBlock` A block containing a web search result. - `Type type` - `BetaManagedAgentsSearchResultCitations citations` Citation settings for this search result. - `boolean enabled` Whether citations are enabled for this search result. - `List content` Array of text content blocks from the search result. - `Type type` - `String text` The text content. minLength: 1 - `String source` The URL source of the search result. minLength: 1 - `String title` The title of the search result. minLength: 1 - `Optional isError` Whether the tool execution resulted in an error. - `class BetaManagedAgentsUserDefineOutcomeEventParams` Parameters for defining an outcome the agent should work toward. The agent begins work on receipt. - `Type type` - `String description` What the agent should produce. This is the task specification. - `Rubric rubric` How to grade the outcome. Text or file reference. - `class BetaManagedAgentsFileRubricParams` Rubric referenced by a file uploaded via the Files API. - `Type type` - `String fileId` ID of the rubric file. - `class BetaManagedAgentsTextRubricParams` Rubric content provided inline as text. - `Type type` - `String content` Rubric content. Plain text or markdown — the grader treats it as freeform text. Maximum 262144 characters. maxLength: 262144 - `Optional maxIterations` Eval→revision cycles before giving up. Default 3, max 20. format: int32 - `class BetaManagedAgentsUserToolResultEventParams` 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. - `Type type` - `String toolUseId` 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?sdk_languages=java#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. minLength: 1, maxLength: 128 - `Optional> content` The result content returned by the tool. - `class BetaManagedAgentsTextBlock` Regular text content. - `class BetaManagedAgentsImageBlock` Image content specified directly as base64 data or as a reference via a URL. - `class BetaManagedAgentsDocumentBlock` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `class BetaManagedAgentsSearchResultBlock` A block containing a web search result. - `Optional isError` Whether the tool execution resulted in an error. - `class BetaManagedAgentsSystemMessageEventParams` 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. - `Type type` - `List content` System content blocks to append. Text-only. - `Type type` - `String text` The text content. minLength: 1 ## Returns - `class BetaManagedAgentsSendSessionEvents` Events that were successfully sent to the session. - `Optional> data` Sent events - `class BetaManagedAgentsUserMessageEvent` A user message event in the session conversation. - `Type type` - `String id` Unique identifier for this event. - `List content` Array of content blocks comprising the user message. - `class BetaManagedAgentsTextBlock` Regular text content. - `Type type` - `String text` The text content. minLength: 1 - `class BetaManagedAgentsImageBlock` Image content specified directly as base64 data or as a reference via a URL. - `Type type` - `Source source` The source of the image data. - `class BetaManagedAgentsBase64ImageSource` Base64-encoded image data. - `Type type` - `String data` Base64-encoded image data. minLength: 1 - `String mediaType` MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp"). minLength: 1 - `class BetaManagedAgentsUrlImageSource` Image referenced by URL. - `Type type` - `String url` URL of the image to fetch. minLength: 1 - `class BetaManagedAgentsFileImageSource` Image referenced by file ID. - `Type type` - `String fileId` ID of a previously uploaded file. minLength: 1 - `class BetaManagedAgentsDocumentBlock` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `Type type` - `Source source` The source of the document data. - `class BetaManagedAgentsBase64DocumentSource` Base64-encoded document data. - `Type type` - `String data` Base64-encoded document data. minLength: 1 - `String mediaType` MIME type of the document (e.g., "application/pdf"). minLength: 1 - `class BetaManagedAgentsPlainTextDocumentSource` Plain text document content. - `Type type` - `String data` The plain text content. minLength: 1 - `MediaType mediaType` MIME type of the text content. Must be "text/plain". - `class BetaManagedAgentsUrlDocumentSource` Document referenced by URL. - `Type type` - `String url` URL of the document to fetch. minLength: 1 - `class BetaManagedAgentsFileDocumentSource` Document referenced by file ID. - `Type type` - `String fileId` ID of a previously uploaded file. minLength: 1 - `Optional context` Additional context about the document for the model. - `Optional title` The title of the document. - `class BetaManagedAgentsRedactedBlock` Placeholder for content withheld by Anthropic model policy. - `Type type` - `Optional processedAt` Timestamp when the agent finished processing this message. format: date-time - `class BetaManagedAgentsUserInterruptEvent` An interrupt event that pauses agent execution and returns control to the user. - `Type type` - `String id` Unique identifier for this event. - `Optional processedAt` Timestamp when the interrupt was processed. format: date-time - `Optional 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 BetaManagedAgentsUserToolConfirmationEvent` A tool confirmation event that approves or denies a pending tool execution. - `Type type` - `String id` Unique identifier for this event. - `Result result` The confirmation result: 'allow' or 'deny'. - `ALLOW("allow")` - `DENY("deny")` - `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](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=java#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. - `Optional denyMessage` Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'. maxLength: 10000 - `Optional processedAt` Timestamp when the confirmation was processed. format: date-time - `Optional sessionThreadId` Set by the server to the subagent thread this confirmation was routed to. Omitted when it was routed to the primary thread. - `class BetaManagedAgentsUserCustomToolResultEvent` Event sent by the client providing the result of a custom tool execution. - `Type type` - `String id` Unique identifier for this event. - `String customToolUseId` The id of the `agent.custom_tool_use` event this result corresponds to. It is also listed in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list?sdk_languages=java#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. - `Optional> content` The result content returned by the tool. - `class BetaManagedAgentsTextBlock` Regular text content. - `class BetaManagedAgentsImageBlock` Image content specified directly as base64 data or as a reference via a URL. - `class BetaManagedAgentsDocumentBlock` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `class BetaManagedAgentsSearchResultBlock` A block containing a web search result. - `Type type` - `BetaManagedAgentsSearchResultCitations citations` Citation settings for this search result. - `boolean enabled` Whether citations are enabled for this search result. - `List content` Array of text content blocks from the search result. - `Type type` - `String text` The text content. minLength: 1 - `String source` The URL source of the search result. minLength: 1 - `String title` The title of the search result. minLength: 1 - `Optional isError` Whether the tool execution resulted in an error. - `Optional processedAt` Timestamp when this result was processed. format: date-time - `Optional sessionThreadId` Set by the server to the subagent thread this result was routed to. Omitted when it was routed to the primary thread. - `class BetaManagedAgentsUserDefineOutcomeEvent` Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference. - `Type type` - `String id` Unique identifier for this event. - `String description` What the agent should produce. Copied from the input event. - `Optional maxIterations` Evaluate-then-revise cycles before giving up. Default 3, max 20. format: int32 - `String outcomeId` Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list. - `LocalDateTime processedAt` Timestamp when the outcome was accepted. format: date-time - `Rubric rubric` How to grade the outcome. File rubrics are currently resolved to their text content; clients should handle both variants. - `class BetaManagedAgentsFileRubric` Rubric referenced by a file uploaded via the Files API. - `Type type` - `String fileId` ID of the rubric file. - `class BetaManagedAgentsTextRubric` Rubric content provided inline as text. - `Type type` - `String content` Rubric content. Plain text or markdown — the grader treats it as freeform text. - `class BetaManagedAgentsUserToolResultEvent` 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 type` - `String id` Unique identifier for this event. - `String toolUseId` 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?sdk_languages=java#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field. - `Optional> content` The result content returned by the tool. - `class BetaManagedAgentsTextBlock` Regular text content. - `class BetaManagedAgentsImageBlock` Image content specified directly as base64 data or as a reference via a URL. - `class BetaManagedAgentsDocumentBlock` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `class BetaManagedAgentsSearchResultBlock` A block containing a web search result. - `Optional isError` Whether the tool execution resulted in an error. - `Optional processedAt` Timestamp when this result was processed. format: date-time - `Optional sessionThreadId` Set by the server to the subagent thread this result was routed to. Omitted when it was routed to the primary thread. - `class BetaManagedAgentsSystemMessageEvent` A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn. - `Type type` - `String id` Unique identifier for this event. - `List content` System content blocks. Text-only. - `Type type` - `String text` The text content. minLength: 1 - `Optional processedAt` Timestamp when this system message was processed. format: date-time ## Example ```java package com.anthropic.example; import com.anthropic.client.AnthropicClient; import com.anthropic.client.okhttp.AnthropicOkHttpClient; import com.anthropic.models.beta.sessions.events.BetaManagedAgentsSendSessionEvents; import com.anthropic.models.beta.sessions.events.BetaManagedAgentsTextBlock; import com.anthropic.models.beta.sessions.events.BetaManagedAgentsUserMessageEventParams; import com.anthropic.models.beta.sessions.events.EventSendParams; import java.util.List; public final class Main { private Main() {} public static void main(String[] args) { AnthropicClient client = AnthropicOkHttpClient.fromEnv(); EventSendParams params = EventSendParams.builder() .sessionId("sesn_011CZkZAtmR3yMPDzynEDxu7") .addUserMessageEvent(List.of(BetaManagedAgentsUserMessageEventParams.Content.ofText(BetaManagedAgentsTextBlock.builder() .text("Where is my order #1234?") .type(BetaManagedAgentsTextBlock.Type.TEXT) .build()))) .build(); BetaManagedAgentsSendSessionEvents betaManagedAgentsSendSessionEvents = client.beta().sessions().events().send(params); } } ``` ### Response (200) ```json { "data": [ { "id": "sevt_011CZkZGPp1iBcp4kaQSihUm", "content": [ { "text": "Where is my order #1234?", "type": "text" } ], "type": "user.message", "processed_at": "2026-03-15T10:00:00Z" } ] } ```