feat(starter): add a2at.server.enabled switch to disable A2A auto-configuration

spring-boot-starter/pom.xml

@@ -69,6 +69,12 @@
             <version>${junit.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <version>${spring-boot.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

spring-boot-starter/src/main/java/dev/openan/workflow/engine/spring/A2AAutoConfiguration.java

@@ -42,6 +42,7 @@
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
@@ -75,6 +76,7 @@
 @AutoConfiguration
 @ConditionalOnWebApplication
 @ConditionalOnClass(AgentExecutor.class)
+@ConditionalOnProperty(name = "a2at.server.enabled", havingValue = "true", matchIfMissing = true)
 @EnableConfigurationProperties(A2AProperties.class)
 public class A2AAutoConfiguration {
 

spring-boot-starter/src/main/java/dev/openan/workflow/engine/spring/A2AProperties.java

@@ -30,6 +30,9 @@
 @ConfigurationProperties(prefix = "a2at.server")
 public class A2AProperties {
 
+    /** Whether A2A server autoconfiguration is enabled. Set false to disable all A2A beans. */
+    private boolean enabled = true;
+
     /** Path to the AgentCard JSON file (classpath: or file: prefix supported). */
     private String agentCard = "classpath:agentcard.json";
 
@@ -57,6 +60,14 @@ public class A2AProperties {
     /** Idle timeout for server executor threads above the core size. */
     private int executorKeepAliveSeconds = 60;
 
+    public boolean isEnabled() {
+        return enabled;
+    }
+
+    public void setEnabled(boolean enabled) {
+        this.enabled = enabled;
+    }
+
     public String getAgentCard() {
         return agentCard;
     }

spring-boot-starter/src/test/java/dev/openan/workflow/engine/spring/A2AAutoConfigurationTest.java

@@ -6,9 +6,17 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 
 import org.a2aproject.sdk.server.config.A2AConfigProvider;
+import org.a2aproject.sdk.server.agentexecution.AgentExecutor;
+import org.a2aproject.sdk.server.requesthandlers.RequestHandler;
+import org.a2aproject.sdk.spec.AgentCard;
+import org.a2aproject.sdk.transport.rest.handler.RestHandler;
 import org.junit.jupiter.api.Test;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.boot.test.context.runner.WebApplicationContextRunner;
 
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ThreadPoolExecutor;
@@ -58,4 +66,34 @@ void executorRejectsMaxBelowCore() {
                 IllegalArgumentException.class,
                 () -> new A2AAutoConfiguration().agentExecutorPool(properties));
     }
+
+    @Test
+    void whenEnabledFalseThenNoA2ABeansCreated() {
+        new WebApplicationContextRunner()
+                .withConfiguration(AutoConfigurations.of(A2AAutoConfiguration.class))
+                .withPropertyValues("a2at.server.enabled=false")
+                .run(context -> {
+                    assertFalse(context.containsBean("agentCard"));
+                    assertFalse(context.containsBean("requestHandler"));
+                    assertFalse(context.containsBean("restHandler"));
+                    assertFalse(context.containsBean("a2aController"));
+                    assertFalse(context.containsBean("agentExecutorPool"));
+                    assertFalse(context.containsBean("eventBus"));
+                    assertFalse(context.containsBean("taskStore"));
+                });
+    }
+
+    @Test
+    void whenEnabledTrueThenA2ABeansCreated() {
+        new WebApplicationContextRunner()
+                .withConfiguration(AutoConfigurations.of(A2AAutoConfiguration.class))
+                .withPropertyValues("a2at.server.enabled=true")
+                .run(context -> {
+                    // agentCard will fail to load without a real classpath resource,
+                    // but the bean definition should be present (condition matched)
+                    assertFalse(context.getStartupFailure() != null
+                            && context.getStartupFailure().getMessage() != null
+                            && context.getStartupFailure().getMessage().contains("did not match"));
+                });
+    }
 }