Struct A2AClientFactory 

pub struct A2AClientFactory { /* private fields */ }

Factory for creating A2AClient instances with automatic protocol negotiation.

Maintains a registry of TransportFactory implementations indexed by protocol and major version. When creating a client from an AgentCard, it selects the best matching transport based on the agent’s declared interfaces and the client’s preferred bindings.

Implementations

impl A2AClientFactory

pub fn builder() -> A2AClientFactoryBuilder

Create a builder for configuring the factory.

pub async fn create_from_card( &self, card: &AgentCard, ) -> Result<A2AClient<Box<dyn Transport>>, A2AError>

Create a client by negotiating the best transport with the agent card.

Selection algorithm (mirrors Go SDK):

1. For each interface in the agent card’s supported_interfaces
2. Look up matching factory by (protocol, major_version)
3. Rank candidates: client preference order, then newest version
4. Try connecting in rank order; first success wins

pub async fn create_from_card_with_interface( &self, card: &AgentCard, ) -> Result<(A2AClient<Box<dyn Transport>>, AgentInterface), A2AError>

Same negotiation as Self::create_from_card, but also returns the AgentInterface that was selected — needed by a caller that must honor that interface’s own declared routing tenant (A2A §8.3.2) on every subsequent request, which the interface list alone doesn’t otherwise surface once a client has been built.