Module protocol 

A2A (Agent-to-Agent) protocol types.

Defines the core data types for the A2A protocol, which enables inter-agent communication over JSON-RPC style messaging.

Core Types

• AgentCard: Metadata describing an agent’s identity and capabilities.
• A2ATask: A unit of work sent between agents.
• A2AMessage: A message within a task (role + content).
• TaskStatus: Lifecycle states for a task.
• A2ARequest / A2AResponse: JSON-RPC style request/response envelope.

Modules

metadata_keys

Standard well-known metadata keys.

Structs

A2AErrorData

Error payload within an A2A JSON-RPC response.

A2AMessage

A message within an A2A task.

A2ARequest

A2A JSON-RPC style request.

A2AResponse

A2A JSON-RPC style response.

A2ATask

A unit of work in the A2A protocol.

A2ATaskDetails

Detailed view of a task including its result and any error message.

A2ATaskResult

Result of a completed A2A task.

A2AWorkflow

A multi-step orchestration submitted via tasks/runWorkflow (P2-8).

AgentCard

Agent metadata card, served at /.well-known/agent-card.json.

AgentInterface

One interface of an agent (v1.0.1 supportedInterfaces[] entry).

AgentSkill

A skill that an agent can perform.

MessageEnvelope

Transport-neutral message envelope shared across HTTP and gRPC (P2-8).

TaskFilter

Filter for listing tasks from a task store (P1-1).

TraceContext

W3C Trace Context (traceparent header) (P2-8).

WorkflowStep

A single unit of work within an A2AWorkflow (P2-8).

Enums

A2ATransport

Transport binding of one agent interface (v1.0.1: three bindings, cumulative — a card may advertise several).

TaskPushNotification

A push notification emitted by a streaming A2A server (P2-1).

TaskStatus

Task lifecycle status.

Constants

A2A_VERSION_V101

A2A v1.0.1 protocol version (the first stable line; Agent Cards restructured to supportedInterfaces[] — incompatible with v0.3’s single-declaration shape).