> ## Documentation Index > Fetch the complete documentation index at: https://docs.prisme.ai/llms.txt > Use this file to discover all available pages before exploring further. # Stream an agent reply via SSE (A2A) > A2A-compliant streaming send. The request body uses the same `MessageSendParams` shape as `messages/send`. The response is delivered as Server-Sent Events (`text/event-stream`): each event is one of `task.status`, `task.message`, `task.artifact`, `task.completed`, `task.failed`, `task.canceled`. Clients must read until they see a terminal event. The `x-draft-mode: true` header bypasses `published_config` resolution. The same HITL approval flow as `messages/send` applies - a streaming task may park in `input-required` until resolved. This automation is also bound to the workspace event `agents.messages.stream` for native event-bus fan-out (WebSocket consumers); that path is out of scope for OpenAPI. ## OpenAPI ````yaml /api-reference/agent-factory/swagger.yml post /v1/agents/{agentId}/messages/stream openapi: 3.0.3 info: version: 1.0.0 title: Agent Factory API description: | Public REST API for the Agent Factory workspace - agents, conversations, messages, tools, artifacts, sharing, ratings, and discovery. Powered by Prisme.ai's runtime; all endpoints are exposed under each workspace's webhook namespace. contact: name: Prisme.ai url: https://prisme.ai servers: - url: https://{host}/v2/workspaces/slug:agent-factory/webhooks description: Prisme.ai workspace webhooks variables: host: default: api.studio.prisme.ai description: API host (override for self-hosted or sandbox) security: - BearerAuth: [] - OrgApiKeyAuth: [] tags: - name: Agents description: Agent CRUD, discovery, AGENTS.md import/export. - name: Access description: Agent access bindings, sharing, and access requests. - name: ApiKeys description: Agent-scoped API key management (mint, revoke, rotate). - name: Publishing description: Publish or discard draft changes on an agent. - name: Ratings description: User ratings on published agents. - name: Profiles description: >- Agent profiles/presets catalog (simple, workflow, agent_light, agent_full, orchestrator). - name: Activity description: Activity feed for agents (events, errors, lifecycle changes). - name: Analytics description: Agent usage analytics (series + summary). - name: Conversations description: Conversations on an agent (CRUD, archive, star). - name: Messages description: Send messages to an agent (synchronous send + SSE stream). - name: Tasks description: Async task lifecycle (list, fetch, cancel, resolve, subscribe). - name: Artifacts description: Generated artifacts (files, code, content) attached to a task. - name: Shares description: Conversation, message, and artifact share-link snapshots. - name: A2A description: Agent-to-agent JSON-RPC 2.0 gateway (well-known agent.json + RPC). - name: Tools description: Per-agent tool catalogue (system tools, MCP servers, function tools). - name: Retention description: Per-agent and org-wide conversation retention policies. - name: Evaluations description: Agent evaluation runs and results. paths: /v1/agents/{agentId}/messages/stream: post: tags: - Messages summary: Stream an agent reply via SSE (A2A) description: | A2A-compliant streaming send. The request body uses the same `MessageSendParams` shape as `messages/send`. The response is delivered as Server-Sent Events (`text/event-stream`): each event is one of `task.status`, `task.message`, `task.artifact`, `task.completed`, `task.failed`, `task.canceled`. Clients must read until they see a terminal event. The `x-draft-mode: true` header bypasses `published_config` resolution. The same HITL approval flow as `messages/send` applies - a streaming task may park in `input-required` until resolved. This automation is also bound to the workspace event `agents.messages.stream` for native event-bus fan-out (WebSocket consumers); that path is out of scope for OpenAPI. operationId: streamMessage parameters: - name: agentId in: path required: true schema: type: string maxLength: 64 - name: x-draft-mode in: header required: false schema: type: boolean description: | When true, the stream exercises the agent's live (draft) config instead of `published_config`. Owners/writers only. requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/MessageSendInput' responses: '200': description: | Server-Sent Events stream of A2A task lifecycle events. Terminates after a `task.completed`, `task.failed`, or `task.canceled` event. content: text/event-stream: schema: type: string description: | Stream of `data: ` lines, each carrying an A2A task lifecycle event. See description for event types. '400': description: Validation error. content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Authentication required. content: application/json: schema: $ref: '#/components/schemas/Error' '403': description: Forbidden. content: application/json: schema: $ref: '#/components/schemas/Error' '404': description: Agent not found. content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: Rate limit exceeded. content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: MessageSendInput: type: object required: - message properties: message: $ref: '#/components/schemas/Message' Error: type: object required: - error - message properties: error: type: string description: >- Stable PascalCase or SNAKE_CASE error code (e.g. AgentNotFound, VALIDATION_ERROR, FORBIDDEN, METHOD_NOT_ALLOWED). message: type: string description: Human-readable error message. details: type: object description: Optional structured context for the error. additionalProperties: true Message: type: object description: A2A v0.3 flat message envelope. properties: message_id: type: string maxLength: 256 role: type: string enum: - user - agent contextId: type: string maxLength: 64 taskId: type: string parts: type: array items: $ref: '#/components/schemas/MessagePart' MessagePart: type: object description: | A2A message part. Discriminated by field presence: `TextPart` (`text`), `FilePart` (`url`/`raw`, `mediaType`, `filename`), `DataPart` (`data`, `mediaType`). additionalProperties: true securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: JWT description: | User-bound credential carrying an identity: either a session JWT or a user access token (`at:*`) generated from the user settings UI. Send as `Authorization: Bearer `. Org API keys (`iak_*`) are **not** accepted here - they carry no user identity. Use the `x-prismeai-api-key` header instead (see `OrgApiKeyAuth`). OrgApiKeyAuth: type: apiKey in: header name: x-prismeai-api-key description: | Organization API key (`iak_{orgSlug}_{uuid}`). Unlike `Authorization: Bearer`, this credential is **not** tied to a user identity - it is bound to the org and its effective access is defined by the scopes / permission rules attached to it (it can be restricted to a single project, or kept broader). For Agent Factory, these keys can be generated directly from the Agent Factory UI (in addition to the AI Governance settings). Send as `x-prismeai-api-key: iak_...`. ````