strands.vended_tools.a2a_client.a2a_client

A2A client tool for communicating with remote A2A-protocol agents.

Provides :func:make_a2a_client, a factory that requires an explicit list of permitted endpoints (with optional :class:~a2a.client.ClientConfig).

The tool is a stateless shim over :class:~strands.agent.a2a_agent.A2AAgent. A fresh A2AAgent is constructed on every call so the tool carries no session state between invocations. Each endpoint may carry its own :class:~a2a.client.ClientConfig to support per-endpoint authentication (bearer tokens, SigV4, OAuth).

A2AClientError

class A2AClientError(RuntimeError)

Defined in: src/strands/vended_tools/a2a_client/a2a_client.py:38

Raised when an A2A operation fails.

AllowedEndpoint

A permitted endpoint: a bare URL string, or a (url, ClientConfig) tuple.

make_a2a_client

def make_a2a_client(
        *,
        name: str = "a2a_client",
        description: str | None = None,
        allowed_endpoints: list[AllowedEndpoint]) -> DecoratedFunctionTool

Defined in: src/strands/vended_tools/a2a_client/a2a_client.py:46

Create an A2A client tool.

Arguments:

• name - Tool name shown to the model.
• description - Tool description shown to the model. When None, generated from DEFAULT_A2A_CLIENT_DESCRIPTION plus the permitted endpoints list.
• allowed_endpoints - Permitted base URLs. Each entry is either a bare URL string (no custom config) or a (url, ClientConfig) tuple for per-endpoint authentication. Any endpoint not in this list is rejected before a network connection is made.

Returns:

A decorated tool that communicates with A2A agents.