A2A Error Codes — Complete Reference

JSON-RPC standard errors

• -32700 Parse error — invalid JSON.
• -32600 Invalid Request — missing required field.
• -32601 Method not found — bad method name.
• -32602 Invalid params — schema violation.
• -32603 Internal error — server bug.

A2A-specific errors

• -32001 Task not found
• -32002 Auth failed
• -32003 Capability unsupported
• -32004 Rate limited
• -32005 Payload too large
• -32006 Task already in terminal state

Error response shape

{
  "jsonrpc": "2.0",
  "id": "req-1",
  "error": {
    "code": -32001,
    "message": "Task not found",
    "data": {"taskId": "task-xyz"}
  }
}