> ## Documentation Index > Fetch the complete documentation index at: https://docs.corti.ai/llms.txt > Use this file to discover all available pages before exploring further. # A2A JSON-RPC binding > The `JSONRPC` protocol binding for A2A v1.0. Accepts a single JSON-RPC 2.0 request whose `method` is one of `SendMessage`, `SendStreamingMessage`, `GetTask`, `ListTasks`, `CancelTask`, or `SubscribeToTask`. Streaming methods (`SendStreamingMessage`, `SubscribeToTask`) respond with `text/event-stream`; all others respond with a single JSON-RPC response. ## OpenAPI ````yaml /agentic/auto-generated-openapi-v2.yml post /v2/agentic/agents/{agentId}/a2a openapi: 3.1.0 info: title: Corti Agent API v2 version: 2.0.0 summary: Manage agents and converse with them over the A2A v1.0 protocol. description: > Version 2 of the Corti Agents REST API. ## What's new in v2 - **Unified `connectors`** — a single, flat, discriminated array replaces the v1 split between `experts`, `mcpServers`, and sub-agents. The envelope is extensible: new connector kinds (`a2a`, `openapi`, `custom`) slot in behind the `type` discriminator without breaking changes. - **Clean CRUD verbs** — `POST` creates, `GET` fetches/lists, `PATCH` performs a *true* partial update, `DELETE` removes. v1's PATCH was effectively a PUT. - **First-class metadata** — `visibility`, `model`, `lifecycle` (now a body field, not a query param), and free-form `labels`. ## A2A v1.0 only The conversational surface speaks **A2A protocol version `1.0` exclusively** (both the `JSONRPC` and `HTTP+JSON` bindings). The deprecated v0.3 binding from v1 is intentionally not carried forward. Per A2A §3.6, clients MUST send the `A2A-Version` header (`Major.Minor`, e.g. `1.0`) on every request to the `/a2a/*` surface, or supply it as the `A2A-Version` query parameter. This surface implements `1.0` only; an absent header is treated as `1.0`. Patch versions MUST NOT be sent. The server echoes the negotiated version in the `A2A-Version` response header. ## Partial updates (PATCH) `PATCH` uses **JSON Merge Patch** semantics (RFC 7386), served under the `application/merge-patch+json` media type: - **Omit a field** → left unchanged. - **`null`** → cleared / reset to its default. - **Arrays** (e.g. `connectors`) → *replaced wholesale*, never merged. To mutate a single connector without replacing the whole array, use the `/connectors` sub-resource endpoints. ## Streaming (Server-Sent Events) The streaming A2A surfaces — `message/stream`, `tasks/subscribe`, and the streaming JSON-RPC methods — respond with `text/event-stream`. The `text/event-stream` media type carries a sequence of Server-Sent Events; the attached schema describes a single event frame. Every event's `data` field is a string carrying a JSON document (`contentMediaType: application/json`); `contentSchema` declares the parsed payload (`StreamResponse` for the `HTTP+JSON` binding, `JSONRPCResponse` for the `JSONRPC` binding). The optional `id` field carries the SSE event id used for resumption via the `Last-Event-ID` request header. contact: name: Corti API Support url: https://corti.ai email: support@corti.ai license: name: Proprietary url: https://corti.ai/terms termsOfService: https://corti.ai/terms servers: - url: https://api.{env}.corti.app description: Corti regional API gateway variables: env: default: eu enum: - eu - us description: Deployment region. security: - bearerAuth: [] tenantHeader: [] tags: - name: Agents description: Create, read, update, and delete agents. - name: Agent Card description: A2A-compliant agent discovery cards. - name: A2A description: Converse with an agent over the A2A v1.0 protocol. - name: Connectors description: Manage the connectors attached to an agent. - name: Usage description: Bucketed invocation history for an agent. - name: Contexts description: Conversational contexts and their tasks. - name: Registry description: Discoverable, pre-built connectors offered by the platform. - name: Artifacts description: Retrieve artifacts produced by tasks. - name: Feedback description: Collect human or automated feedback on tasks and messages. paths: /v2/agentic/agents/{agentId}/a2a: parameters: - $ref: '#/components/parameters/AgentId' - $ref: '#/components/parameters/A2AVersionHeader' post: tags: - A2A summary: A2A JSON-RPC binding description: > The `JSONRPC` protocol binding for A2A v1.0. Accepts a single JSON-RPC 2.0 request whose `method` is one of `SendMessage`, `SendStreamingMessage`, `GetTask`, `ListTasks`, `CancelTask`, or `SubscribeToTask`. Streaming methods (`SendStreamingMessage`, `SubscribeToTask`) respond with `text/event-stream`; all others respond with a single JSON-RPC response. operationId: A2AJsonRpc requestBody: required: true description: A single JSON-RPC 2.0 request envelope. content: application/json: schema: $ref: '#/components/schemas/A2AJSONRPCRequest' examples: messageSend: summary: SendMessage value: jsonrpc: '2.0' id: '1' method: SendMessage params: message: role: ROLE_USER messageId: msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73 parts: - text: Code this encounter. responses: '200': description: > A single JSON-RPC response (non-streaming methods), or an `text/event-stream` for the streaming methods (`SendStreamingMessage`, `SubscribeToTask`) where each event's `data` is a JSON-encoded `JSONRPCResponse`. headers: A2A-Version: $ref: '#/components/headers/A2AVersion' content: application/json: schema: $ref: '#/components/schemas/A2AJSONRPCResponse' example: jsonrpc: '2.0' id: msg-001 result: task: id: task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62 contextId: ctx.0192f4c8-3d6b-7c4f-a02b-4d9e7f3c8b51 status: state: TASK_STATE_COMPLETED text/event-stream: schema: $ref: '#/components/schemas/A2AJSONRPCStreamEventResponse' example: event: message data: >- {"jsonrpc":"2.0","id":"msg-001","result":{"task":{"id":"task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62","contextId":"ctx.0192f4c8-3d6b-7c4f-a02b-4d9e7f3c8b51","status":{"state":"TASK_STATE_COMPLETED"}}}} '401': $ref: '#/components/responses/Unauthorized' '404': $ref: '#/components/responses/NotFound' components: parameters: AgentId: name: agentId in: path required: true description: Agent identifier (prefixed UUIDv7). schema: $ref: '#/components/schemas/CommonAgentIDValue' A2AVersionHeader: name: A2A-Version in: header required: false description: >- A2A protocol version in `Major.Minor` form (A2A §3.6). Optional; defaults to `1.0` when absent. This surface implements `1.0` only. Patch versions MUST NOT be sent and are not considered during negotiation. schema: type: string pattern: ^\d+\.\d+$ default: '1.0' schemas: A2AJSONRPCRequest: type: object description: A JSON-RPC 2.0 request envelope. required: - jsonrpc - method - id properties: jsonrpc: const: '2.0' description: JSON-RPC protocol version; always `2.0`. id: oneOf: - type: string - type: integer examples: - msg-001 - 42 method: type: string enum: - SendMessage - SendStreamingMessage - GetTask - ListTasks - CancelTask - SubscribeToTask description: JSON-RPC method name (PascalCase on the wire). examples: - SendMessage params: type: object additionalProperties: true description: JSON-RPC params object. example: message: role: ROLE_USER parts: - text: What is the ICD-10 code for asthma? A2AJSONRPCResponse: type: object description: A JSON-RPC 2.0 response envelope. required: - jsonrpc - id properties: jsonrpc: const: '2.0' description: JSON-RPC protocol version; always `2.0`. id: oneOf: - type: string - type: integer - type: 'null' examples: - msg-001 - 42 - null result: type: object additionalProperties: true description: JSON-RPC result object (present on success). example: task: id: task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62 error: type: object required: - code - message properties: code: type: integer description: JSON-RPC error code. message: type: string description: Human-readable error message. data: type: object additionalProperties: true description: Additional error details. description: JSON-RPC error object (present on failure). examples: - code: -32600 message: Invalid Request A2AJSONRPCStreamEventResponse: description: An SSE event carrying a JSON-RPC streaming response. allOf: - $ref: '#/components/schemas/A2ASSEEvent' - type: object properties: data: type: string contentMediaType: application/json contentSchema: $ref: '#/components/schemas/A2AJSONRPCResponse' description: 'SSE payload: a JSON-RPC streaming response.' CommonAgentIDValue: type: string format: agent-id description: >- Agent identifier. Accepts `agt.` or a bare UUIDv7 on input; always returned prefixed. pattern: ^(agt\.)?[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$ examples: - agt.0192f4c8-2c5a-7b3e-9f1a-3c8d6e2b7a40 A2ASSEEvent: type: object description: >- A single Server-Sent Event frame (W3C SSE wire format). The server currently writes only `id` and `data` lines; `event` and `retry` are declared for forward compatibility but not sent. required: - data properties: data: type: string contentMediaType: application/json description: SSE payload (JSON-encoded). event: type: string description: Event type. Absent for the default `message` event. id: type: string description: | Opaque event id. Clients echo the most recent value in the `Last-Event-ID` header to resume a dropped stream. retry: type: integer minimum: 0 description: Reconnection time in milliseconds the client should use. CommonErrorResponse: type: object description: > Corti management-plane error envelope, used by all non-A2A endpoints. - **Standard** — when the error chain contains at least one `PublicError`, `code` and `message` come from the outermost `PublicError` and `details` is merged across the whole chain (outer values take precedence). - **Fallback** — when the chain contains no `PublicError`, the response is a generic `500` carrying a `requestId` for support reference. - **Validation** — a single `PublicError` whose `details.validationErrors` lists the offending fields. Field names use camelCase on the wire (e.g. `requestId`, `howToFix`). The free-form `details` object may carry arbitrary caller-defined keys. Rate limiting (HTTP 429) is not yet implemented; the server does not emit a 429 response. required: - error properties: error: type: object required: - code - message properties: code: type: string description: Stable, machine-readable, SCREAMING_SNAKE_CASE error code. examples: - ASSIGNMENT_CONFLICT - VALIDATION_FAILED - INTERNAL_ERROR message: type: string description: Human-readable explanation. howToFix: type: string description: Optional guidance for the caller to resolve the error. details: type: object description: | Structured context, merged from every `PublicError` in the chain (outer values win). Omitted on the generic fallback response. additionalProperties: true properties: validationErrors: type: array description: Present when `code` is `VALIDATION_FAILED`. items: type: object required: - field - reason properties: field: type: string description: The field that failed validation. reason: type: string description: Why the field failed validation. requestId: type: string description: > Correlation ID from request middleware. Included only on the generic `500` fallback so consumers can quote it in support requests. description: The error object with code, message, and optional details. examples: - error: code: ASSIGNMENT_CONFLICT message: could not complete assignment details: assignment_id: asg_99 expert_id: exp_42 - error: code: VALIDATION_FAILED message: validation failed details: validationErrors: - field: email reason: invalid format - field: name reason: required - error: code: INTERNAL_ERROR message: internal server error requestId: req_abc123 headers: A2AVersion: description: >- The A2A protocol `Major.Minor` version the server used to handle the request. schema: type: string examples: - '1.0' responses: Unauthorized: description: Missing or invalid credentials. content: application/json: schema: $ref: '#/components/schemas/CommonErrorResponse' NotFound: description: The resource does not exist or is not visible to the caller. content: application/json: schema: $ref: '#/components/schemas/CommonErrorResponse' securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: OAuth 2.0 / OIDC bearer token. tenantHeader: type: apiKey in: header name: Tenant-Name description: The tenant the request operates within. ````