fix: support complete agent card URL in A2ACardResolver

README.md

@@ -436,7 +436,7 @@ If you want to use the HTTP+JSON/REST transport, you'll need to add a relevant d
 
 ```java
 // First, get the agent card for the A2A server agent you want to connect to
-AgentCard agentCard = new A2ACardResolver("http://localhost:1234").getAgentCard();
+AgentCard agentCard = A2ACardResolver.builder().baseUrl("http://localhost:1234").build().getWellKnownAgentCard();
 
 // Specify configuration for the ClientBuilder
 ClientConfig clientConfig = new ClientConfig.Builder()
@@ -776,7 +776,7 @@ gRPC and REST transports are also available:
 #### 3. Create the v0.3 client
 
 ```java
-AgentCard card = new A2ACardResolver("http://localhost:1234").getAgentCard();
+AgentCard card = A2ACardResolver.builder().baseUrl("http://localhost:1234").build().getWellKnownAgentCard();
 
 // Find the v0.3 interface from the agent card
 AgentInterface v03Interface = card.supportedInterfaces().stream()

client/base/src/main/java/org/a2aproject/sdk/A2A.java

@@ -393,7 +393,14 @@ public static AgentCard getAgentCard(String agentUrl, String relativeCardPath, M
      * @throws org.a2aproject.sdk.spec.A2AClientJSONError if the response body cannot be decoded as JSON or validated against the AgentCard schema
      */
     public static AgentCard getAgentCard(A2AHttpClient httpClient, String agentUrl, String relativeCardPath, Map<String, String> authHeaders) throws A2AClientError, A2AClientJSONError  {
-        A2ACardResolver resolver = new A2ACardResolver(httpClient, agentUrl, "", relativeCardPath, authHeaders);
-        return resolver.getAgentCard();
+        A2ACardResolver resolver = A2ACardResolver.builder()
+                .httpClient(httpClient)
+                .baseUrl(agentUrl)
+                .agentCardPath(relativeCardPath)
+                .authHeaders(authHeaders)
+                .build();
+        return (relativeCardPath == null || relativeCardPath.isBlank())
+                ? resolver.getWellKnownAgentCard()
+                : resolver.getConfiguredAgentCard();
     }
 }

examples/helloworld/client/src/main/java/org/a2aproject/sdk/examples/helloworld/HelloWorldClient.java

@@ -53,7 +53,7 @@ public class HelloWorldClient {
     public static void main(String[] args) {
         OpenTelemetrySdk openTelemetrySdk = null;
         try {
-            AgentCard publicAgentCard = new A2ACardResolver(SERVER_URL).getAgentCard();
+            AgentCard publicAgentCard = A2ACardResolver.builder().baseUrl(SERVER_URL).build().getWellKnownAgentCard();
             System.out.println("Successfully fetched public agent card:");
             System.out.println(JsonUtil.toJson(publicAgentCard));
             System.out.println("Using public agent card for client initialization (default).");

extras/http-client-vertx/README.md

@@ -85,8 +85,8 @@ The Vert.x HTTP client is automatically discovered via **Java SPI (Service Provi
 
 ```java
 // No changes needed - A2A SDK automatically uses VertxA2AHttpClient
-A2ACardResolver resolver = new A2ACardResolver("http://localhost:9999");
-AgentCard card = resolver.getAgentCard(); // Uses Vert.x under the hood
+A2ACardResolver resolver = A2ACardResolver.builder().baseUrl("http://localhost:9999").build();
+AgentCard card = resolver.getWellKnownAgentCard(); // Uses Vert.x under the hood
 
 // Client creation also uses Vert.x automatically
 Client client = Client.builder(card)
@@ -112,8 +112,8 @@ The module works out-of-the-box with sensible defaults:
 // With vertx-http-client on the classpath, it automatically uses VertxA2AHttpClient
 
 // Example 1: Fetching agent card
-A2ACardResolver resolver = new A2ACardResolver("http://localhost:9999");
-AgentCard card = resolver.getAgentCard();
+A2ACardResolver resolver = A2ACardResolver.builder().baseUrl("http://localhost:9999").build();
+AgentCard card = resolver.getWellKnownAgentCard();
 
 // Example 2: Using REST transport (uses HTTP client internally)
 Client client = Client.builder(card)