fix: harden A2A SDK 1.0 integration

Author: March-77

spring-ai-alibaba-agent-framework/src/main/java/com/alibaba/cloud/ai/graph/agent/a2a/A2aNodeActionWithConfig.java

@@ -37,7 +37,12 @@ public class AgentCardWrapper {
 
 	private static final String JSONRPC_TRANSPORT = TransportProtocol.JSONRPC.asString();
 
-	private AgentCard agentCard;
+	private static final String LEGACY_PROTOCOL_VERSION = "0.3";
+
+	private volatile AgentCard agentCard;
+
+	public record AgentEndpoint(String url, String protocolBinding, String protocolVersion, String tenant) {
+	}
 
 	public AgentCardWrapper(AgentCard agentCard) {
 		this.agentCard = agentCard;
@@ -52,7 +57,7 @@ public String description() {
 	}
 
 	public String url() {
-		return preferredInterface().url();
+		return endpoint().url();
 	}
 
 	public AgentProvider provider() {
@@ -111,16 +116,28 @@ public List<AgentInterface> additionalInterfaces() {
 		}
 		return this.agentCard.additionalInterfaces()
 			.stream()
-			.map(agentInterface -> new AgentInterface(agentInterface.transport(), agentInterface.url()))
+			.map(agentInterface -> legacyInterface(agentInterface.transport(), agentInterface.url()))
 			.toList();
 	}
 
 	public String preferredTransport() {
-		return preferredInterface().protocolBinding();
+		return endpoint().protocolBinding();
 	}
 
 	public String protocolVersion() {
-		return preferredInterface().protocolVersion();
+		return endpoint().protocolVersion();
+	}
+
+	public String tenant() {
+		return endpoint().tenant();
+	}
+
+	/**
+	 * Select the endpoint once so callers can build and send a request from one
+	 * immutable agent-card snapshot.
+	 */
+	public AgentEndpoint endpoint() {
+		return preferredEndpoint(this.agentCard);
 	}
 
 	public AgentCard getAgentCard() {
@@ -131,27 +148,36 @@ public void setAgentCard(AgentCard agentCard) {
 		this.agentCard = agentCard;
 	}
 
-	private AgentInterface preferredInterface() {
-		List<AgentInterface> supportedInterfaces = this.agentCard.supportedInterfaces();
+	protected final AgentEndpoint preferredEndpoint(AgentCard agentCard) {
+		AgentInterface agentInterface = preferredInterface(agentCard);
+		String protocolVersion = agentInterface.protocolVersion();
+		if (protocolVersion == null || protocolVersion.isBlank()) {
+			throw new IllegalStateException("JSONRPC interface does not declare a protocol version");
+		}
+		return new AgentEndpoint(agentInterface.url(), agentInterface.protocolBinding(), protocolVersion,
+				agentInterface.tenant());
+	}
+
+	private AgentInterface preferredInterface(AgentCard agentCard) {
+		List<AgentInterface> supportedInterfaces = agentCard.supportedInterfaces();
 		if (supportedInterfaces != null) {
 			for (AgentInterface agentInterface : supportedInterfaces) {
 				if (agentInterface != null && isJsonRpc(agentInterface.protocolBinding())) {
 					return agentInterface;
 				}
 			}
 		}
-		if (this.agentCard.url() != null) {
-			String transport = this.agentCard.preferredTransport() == null ? JSONRPC_TRANSPORT
-					: this.agentCard.preferredTransport();
+		if (agentCard.url() != null) {
+			String transport = agentCard.preferredTransport() == null ? JSONRPC_TRANSPORT : agentCard.preferredTransport();
 			if (isJsonRpc(transport)) {
-				return new AgentInterface(transport, this.agentCard.url());
+				return legacyInterface(transport, agentCard.url());
 			}
 		}
-		List<Legacy_0_3_AgentInterface> additionalInterfaces = this.agentCard.additionalInterfaces();
+		List<Legacy_0_3_AgentInterface> additionalInterfaces = agentCard.additionalInterfaces();
 		if (additionalInterfaces != null) {
 			for (Legacy_0_3_AgentInterface agentInterface : additionalInterfaces) {
 				if (agentInterface != null && isJsonRpc(agentInterface.transport())) {
-					return new AgentInterface(agentInterface.transport(), agentInterface.url());
+					return legacyInterface(agentInterface.transport(), agentInterface.url());
 				}
 			}
 		}
@@ -161,4 +187,8 @@ private AgentInterface preferredInterface() {
 	private boolean isJsonRpc(String transport) {
 		return transport != null && JSONRPC_TRANSPORT.equalsIgnoreCase(transport);
 	}
+
+	private AgentInterface legacyInterface(String transport, String url) {
+		return new AgentInterface(transport, url, null, LEGACY_PROTOCOL_VERSION);
+	}
 }