> ## Documentation Index
> Fetch the complete documentation index at: https://docs.celesto.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# A2A Types

> Reference for A2A protocol type definitions including JSONRPCRequest, JSONRPCResponse, AgentCard, AgentSkill, and message types from the a2a-sdk.

The A2A protocol uses types from the `a2a-sdk` package for agent-to-agent communication. These types follow the A2A protocol v0.3.0 specification.

## Core Types

### JSONRPCRequest

Represents a JSON-RPC request in the A2A protocol.

```python theme={null} theme={null}
from a2a.types import JSONRPCRequest
```

**Fields:**

* `id` - Unique identifier for the request
* `method` - The RPC method to call (e.g., "message/send", "message/stream")
* `params` - Parameters for the method
* `jsonrpc` - Protocol version ("2.0")

### JSONRPCResponse

Represents a JSON-RPC response.

```python theme={null} theme={null}
from a2a.types import JSONRPCResponse
```

**Fields:**

* `id` - Request identifier this response corresponds to
* `result` - The result data (if successful)
* `error` - Error information (if failed)
* `jsonrpc` - Protocol version ("2.0")

### JSONRPCError

Represents an error in a JSON-RPC response.

```python theme={null} theme={null}
from a2a.types import JSONRPCError
```

**Fields:**

* `code` - Numeric error code
* `message` - Human-readable error message
* `data` - Additional error details (optional)

### AgentCard

The agent card manifest that describes the agent's capabilities.

```python theme={null} theme={null}
from a2a.types import AgentCard
```

**Fields:**

* `name` - Agent name
* `description` - Agent description
* `url` - Agent base URL
* `version` - Agent version
* `skills` - List of agent skills
* `capabilities` - Supported capabilities
* `additionalInterfaces` - Additional communication interfaces
* `securitySchemes` - Authentication schemes
* `security` - Security requirements
* `defaultInputModes` - Default input content types
* `defaultOutputModes` - Default output content types
* `supportsAuthenticatedExtendedCard` - Whether extended card is supported
* `signatures` - Cryptographic signatures

### AgentSkill

Describes a specific skill or capability the agent can perform.

```python theme={null} theme={null}
from a2a.types import AgentSkill
```

**Fields:**

* `name` - Skill identifier
* `description` - Skill description
* `tags` - Categorization tags (optional)
* `examples` - Usage examples (optional)

### AgentCapabilities

Describes the technical capabilities supported by the agent.

```python theme={null} theme={null}
from a2a.types import AgentCapabilities
```

**Fields:**

* `streaming` - Whether the agent supports streaming responses
* `statefulness` - Whether the agent maintains conversation state
* `asyncProcessing` - Whether the agent supports asynchronous task processing

### SendStreamingMessageRequest

A specialized request type for streaming messages.

```python theme={null} theme={null}
from a2a.types import SendStreamingMessageRequest
```

Extends `JSONRPCRequest` with streaming-specific parameters.

### Task

Represents an asynchronous task.

```python theme={null} theme={null}
from a2a.types import Task
```

**Fields:**

* `id` - Task identifier
* `status` - Current task status
* `state` - Task state information
* `created` - Creation timestamp
* `updated` - Last update timestamp

### TaskState

Enum representing task state values.

```python theme={null} theme={null}
from a2a.types import TaskState
```

**Values:**

* `pending` - Task is queued
* `working` - Task is in progress
* `completed` - Task finished successfully
* `failed` - Task encountered an error
* `cancelled` - Task was cancelled

### TaskStatus

Represents the current status details of a task.

```python theme={null} theme={null}
from a2a.types import TaskStatus
```

**Fields:**

* `state` - Current task state (`TaskState`)
* `progress` - Progress percentage (0-100, optional)
* `message` - Status message (optional)

```python theme={null} theme={null}
from a2a.types import TaskState, TaskStatus

in_progress = TaskStatus(state=TaskState.working)
done = TaskStatus(state=TaskState.completed)
```

## Usage Example

```python theme={null} theme={null}
from a2a.types import (
    AgentCard,
    AgentCapabilities,
    AgentSkill,
    JSONRPCRequest,
    JSONRPCResponse,
    JSONRPCError,
)

# Create an agent card
card = AgentCard(
    name="My Agent",
    description="A helpful assistant",
    url="http://localhost:8000",
    version="1.0.0",
    skills=[
        AgentSkill(
            name="search",
            description="Search the web for information"
        )
    ],
    capabilities=AgentCapabilities(
        streaming=True,
        statefulness=True,
        asyncProcessing=True
    ),
)

# Handle a JSON-RPC request
request = JSONRPCRequest(
    id="123",
    method="message/send",
    params={"message": "Hello"},
    jsonrpc="2.0"
)

# Create a response
response = JSONRPCResponse(
    id=request.id,
    result={"message": "Hello! How can I help?"},
    jsonrpc="2.0"
)
```

## Import Path

```python theme={null} theme={null}
from a2a.types import (
    AgentCapabilities,
    AgentCard,
    AgentSkill,
    JSONRPCError,
    JSONRPCRequest,
    JSONRPCResponse,
    SendStreamingMessageRequest,
    Task,
    TaskState,
    TaskStatus,
)
```

Source: `/home/daytona/workspace/source/src/agentor/a2a.py:4`