gRPC Transport

gRPC support is first-class for client and server integrations.

Client side

Use a2a::client::GrpcTransport with a resolved interface and either:

• a std::shared_ptr<grpc::Channel> for real gRPC calls, or
• a custom GrpcTransport::RpcClient for tests and embedded adapters.

The transport supports unary task operations, streaming send, task subscription, and push-notification config lifecycle calls.

Server side

a2a::server::GrpcServerTransport implements lf::a2a::v1::A2AService::Service and routes RPCs to the dispatcher.

It supports:

• SendMessage
• SendStreamingMessage
• GetTask
• ListTasks
• CancelTask
• SubscribeToTask
• Push-notification config RPCs
• GetExtendedAgentCard

Metadata and extensions

The server transport recognizes A2A metadata such as a2a-version and can validate required extensions through GrpcServerTransportOptions::required_extensions.

Example

See examples/apps/grpc_server/main.cpp.