A2A

Use Biggy's Alpha agent via the A2A protocol so your own AI agents can send messages, stream responses, and poll task status using a standard JSON-RPC 2.0 interface.

🚧 Authentication
All BigPanda APIs require Bearer Token Authorization in the call headers.
This API uses the User API Key type of Authorization token.

❗ Rate limitations
To maintain quality of service, the Biggy API is limited to 100 requests per minute. Additional requests will return a 429 response code and the request will need to be retried.

Methods

All interactions use JSON-RPC 2.0 over the single /a2a/biggy-agent endpoint. The method field determines the operation.

The following methods are available:

Method	Description
`message/send`	Send a message and receive the full response synchronously
`message/stream`	Send a message and stream the response as server-sent events (SSE).
`tasks/get`	Poll the status and result of a previous task

Message format

Messages are composed of parts. Currently only text parts are supported.

Field	Type	Required	Description
`params.message.parts`	array	Yes	Array of message parts
`params.message.parts[].kind`	string	Yes	Must be `"text"`
`params.message.parts[].text`	string	Yes	The text content
`params.thread.threadId`	string	No	Thread ID to continue a conversation

Threading

A2A supports multi-turn conversations via threads.

New conversation: Omit thread or pass "threadId": "". The response will include a generated threadId.

Continue conversation: Pass the threadId from a previous response to carry forward conversation history.

Thread IDs: Alphanumeric, hyphens, and underscores only. Max 128 characters.

The server retains up to 100 messages per thread.

Message and thread limits

Constraint	Value
Max message parts	10
Max text per part	5,000 characters
Max total query length	20,000 characters
Max thread ID length	128 characters

Error response format

Errors are returned as JSON-RPC error objects, not HTTP status codes (the HTTP status is always 200 for JSON-RPC responses).

Code	Description
-32600	Invalid request (missing or wrong `jsonrpc` version)
-32601	Method not found (unsupported `method` value)
-32602	Invalid params (validation failure, bad input)
-32000	Server error (unexpected internal failure)

message/send (synchronous) example

Sends a message to the agent and blocks until the full response is ready.

Request

Response

{
    "jsonrpc": "2.0",
    "id": "1",
    "result": {
        "thread": { "threadId": "a1b2c3d4" },
        "taskId": "6830f1a2e3b4c5d6e7f80001",
        "artifacts": [
            {
                "parts": [{ "kind": "text", "text": "Based on the historical data..." }]
            }
        ]
    }
}

message/stream (SSE) example

Sends a message and streams the response as server-sent (SSE) Events. This method is useful for long-running queries where you want incremental output.

Request

SSE Events

The response is a text/event-stream with the following event types:

Event	Description
`start`	Emitted once at the beginning. Contains `thread`, `taskId`, and the JSON-RPC envelope.
`delta`	Emitted as chunks arrive. Contains `{ "text": "..." }` with the incremental text.
`final`	Emitted once when complete. Contains the full JSON-RPC success response with `artifacts`.
`error`	Emitted if an error occurs. Contains a JSON-RPC error response.

Start event

{
    "jsonrpc": "2.0",
    "id": "1",
    "thread": { "threadId": "a1b2c3d4" },
    "taskId": "6830f1a2e3b4c5d6e7f80001"
}

Delta event

{ "text": "Based on the " }

Final event

{
    "jsonrpc": "2.0",
    "id": "1",
    "result": {
        "thread": { "threadId": "a1b2c3d4" },
        "taskId": "6830f1a2e3b4c5d6e7f80001",
        "artifacts": [
            {
                "parts": [{ "kind": "text", "text": "Based on the historical data..." }]
            }
        ]
    }
}

tasks/get (polling) example

Retrieves the status and result of a previously created task by its taskId.

The following are the possible task statuses:

Status	Meaning
`running`	Task is still in progress
`completed`	Task finished successfully (artifacts included)
`failed`	Task failed (error details included)
`not_found`	No task found with the given ID

Request

Response (completed)

{
    "jsonrpc": "2.0",
    "id": "1",
    "result": {
        "taskId": "6830f1a2e3b4c5d6e7f80001",
        "status": "completed",
        "artifacts": [
            {
                "parts": [{ "kind": "text", "text": "Based on the historical data..." }]
            }
        ]
    }
}

Response (still running)

{
    "jsonrpc": "2.0",
    "id": "1",
    "result": {
        "taskId": "6830f1a2e3b4c5d6e7f80001",
        "status": "running"
    }
}

Methods#

Message format#

Threading#

Message and thread limits#

Error response format#

message/send (synchronous) example#

message/stream (SSE) example#

SSE Events#

tasks/get (polling) example#

Methods

Message format

Threading

Message and thread limits

Error response format

message/send (synchronous) example

message/stream (SSE) example

SSE Events

tasks/get (polling) example