a2a.client.client_factory module

class a2a.client.client_factory.ClientFactory(config: ClientConfig, consumers: list[Callable[[tuple[Task, TaskStatusUpdateEvent | TaskArtifactUpdateEvent | None] | Message, AgentCard], Coroutine[None, Any, Any]]] | None = None)

Bases: object

ClientFactory is used to generate the appropriate client for the agent.

The factory is configured with a ClientConfig and optionally a list of `Consumer`s to use for all generated `Client`s. The expected use is:

factory = ClientFactory(config, consumers)
# Optionally register custom client implementations
factory.register('my_customer_transport', NewCustomTransportClient)
# Then with an agent card make a client with additional consumers and
# interceptors
client = factory.create(card, additional_consumers, interceptors)

Now the client can be used consistently regardless of the transport. This aligns the client configuration with the server’s capabilities.

async classmethod connect(agent: str | AgentCard, client_config: ClientConfig | None = None, consumers: list[Callable[[tuple[Task, TaskStatusUpdateEvent | TaskArtifactUpdateEvent | None] | Message, AgentCard], Coroutine[None, Any, Any]]] | None = None, interceptors: list[ClientCallInterceptor] | None = None, relative_card_path: str | None = None, resolver_http_kwargs: dict[str, Any] | None = None, extra_transports: dict[str, Callable[[AgentCard, str, ClientConfig, list[ClientCallInterceptor]], ClientTransport]] | None = None, extensions: list[str] | None = None, signature_verifier: Callable[[AgentCard], None] | None = None) → Client

Convenience method for constructing a client.

Constructs a client that connects to the specified agent. Note that creating multiple clients via this method is less efficient than constructing an instance of ClientFactory and reusing that.

# This will search for an AgentCard at /.well-known/agent-card.json
my_agent_url = 'https://travel.agents.example.com'
client = await ClientFactory.connect(my_agent_url)
Parameters:

  • agent – The base URL of the agent, or the AgentCard to connect to.

  • client_config – The ClientConfig to use when connecting to the agent.

  • consumers – A list of Consumer methods to pass responses to.

  • interceptors – A list of interceptors to use for each request. These are used for things like attaching credentials or http headers to all outbound requests.

  • relative_card_path – If the agent field is a URL, this value is used as the relative path when resolving the agent card. See A2AAgentCardResolver.get_agent_card for more details.

  • resolver_http_kwargs – Dictionary of arguments to provide to the httpx client when resolving the agent card. This value is provided to A2AAgentCardResolver.get_agent_card as the http_kwargs parameter.

  • extra_transports – Additional transport protocols to enable when constructing the client.

  • extensions – List of extensions to be activated.

  • signature_verifier – A callable used to verify the agent card’s signatures.

Returns:

A Client object.

create(card: AgentCard, consumers: list[Callable[[tuple[Task, TaskStatusUpdateEvent | TaskArtifactUpdateEvent | None] | Message, AgentCard], Coroutine[None, Any, Any]]] | None = None, interceptors: list[ClientCallInterceptor] | None = None, extensions: list[str] | None = None) → Client

Create a new Client for the provided AgentCard.

Parameters:

  • card – An AgentCard defining the characteristics of the agent.

  • consumers – A list of Consumer methods to pass responses to.

  • interceptors – A list of interceptors to use for each request. These are used for things like attaching credentials or http headers to all outbound requests.

  • extensions – List of extensions to be activated.

Returns:

A Client object.

Raises:

  • If there is no valid matching of the client configuration with the –

  • server configuration, a ValueError is raised. –

register(label: str, generator: Callable[[AgentCard, str, ClientConfig, list[ClientCallInterceptor]], ClientTransport]) → None

Register a new transport producer for a given transport label.

a2a.client.client_factory.minimal_agent_card(url: str, transports: list[str] | None = None) → AgentCard

Generates a minimal card to simplify bootstrapping client creation.

This minimal card is not viable itself to interact with the remote agent. Instead this is a shorthand way to take a known url and transport option and interact with the get card endpoint of the agent server to get the correct agent card. This pattern is necessary for gRPC based card access as typically these servers won’t expose a well known path card.