refactor(server): Simplify parameter handling in McpServerPromptFactory and enhance prompt argument verification in tests

Author: codeboyzhou

src/main/java/com/github/codeboyzhou/mcp/declarative/server/component/McpServerPromptFactory.java

@@ -11,7 +11,6 @@
 import java.lang.reflect.Method;
 import java.lang.reflect.Parameter;
 import java.util.ArrayList;
-import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Stream;
@@ -38,9 +37,8 @@ public McpServerFeatures.SyncPromptSpecification create(Class<?> clazz, Method m
           Object result;
           try {
             Object instance = InjectorProvider.getInstance().getInjector().getInstance(clazz);
-            Map<String, Object> typedParameters =
-                asTypedParameters(method, promptArguments, request.arguments());
-            result = method.invoke(instance, typedParameters.values().toArray());
+            List<Object> typedValues = asTypedParameterValues(method, request.arguments());
+            result = method.invoke(instance, typedValues.toArray());
           } catch (Exception e) {
             log.error("Error invoking prompt method", e);
             result = e + ": " + e.getMessage();
@@ -70,20 +68,23 @@ private List<McpSchema.PromptArgument> createPromptArguments(Method method) {
     return promptArguments;
   }
 
-  private Map<String, Object> asTypedParameters(
-      Method method, List<McpSchema.PromptArgument> arguments, Map<String, Object> parameters) {
-    Class<?>[] parameterTypes = method.getParameterTypes();
-    Map<String, Object> typedParameters = new LinkedHashMap<>(parameters.size());
+  private List<Object> asTypedParameterValues(Method method, Map<String, Object> parameters) {
+    Parameter[] methodParams = method.getParameters();
+    List<Object> typedValues = new ArrayList<>(methodParams.length);
 
-    for (int i = 0, size = arguments.size(); i < size; i++) {
-      final String parameterName = arguments.get(i).name();
-      final Object parameterValue = parameters.get(parameterName);
-      // Fill in a default value when the parameter is not specified
+    for (Parameter param : methodParams) {
+      Object rawValue = null;
+      if (param.isAnnotationPresent(McpPromptParam.class)) {
+        McpPromptParam promptParam = param.getAnnotation(McpPromptParam.class);
+        rawValue = parameters.get(promptParam.name());
+      }
+      // Fill in a default value when the parameter is not specified or unannotated
       // to ensure that the parameter type is correct when calling method.invoke()
-      Object typedParameterValue = Types.convert(parameterValue, parameterTypes[i]);
-      typedParameters.put(parameterName, typedParameterValue);
+      Class<?> targetType = param.getType();
+      Object typed = Types.convert(rawValue, targetType);
+      typedValues.add(typed);
     }
 
-    return typedParameters;
+    return typedValues;
   }
 }

src/test/java/com/github/codeboyzhou/mcp/declarative/McpServersTest.java

@@ -14,6 +14,7 @@
 import com.github.codeboyzhou.mcp.declarative.server.factory.McpSseServerInfo;
 import com.github.codeboyzhou.mcp.declarative.server.factory.McpStreamableServerInfo;
 import com.github.codeboyzhou.mcp.declarative.test.TestSimpleMcpStdioServer;
+import com.github.codeboyzhou.mcp.declarative.util.ObjectMappers;
 import io.modelcontextprotocol.client.McpClient;
 import io.modelcontextprotocol.client.McpSyncClient;
 import io.modelcontextprotocol.client.transport.HttpClientSseClientTransport;
@@ -23,6 +24,7 @@
 import io.modelcontextprotocol.spec.McpSchema;
 import java.time.Duration;
 import java.util.List;
+import java.util.Map;
 import java.util.Random;
 import org.junit.jupiter.api.Test;
 
@@ -158,6 +160,7 @@ private void verify(McpSyncClient client) {
     verifyResourcesRegistered(client);
     verifyPromptsRegistered(client);
     verifyToolsRegistered(client);
+    verifyPromptsCalled(client);
   }
 
   private void verifyServerInfo(McpSyncClient client) {
@@ -181,11 +184,30 @@ private void verifyResourcesRegistered(McpSyncClient client) {
   private void verifyPromptsRegistered(McpSyncClient client) {
     List<McpSchema.Prompt> prompts = client.listPrompts().prompts();
     assertEquals(1, prompts.size());
+
     McpSchema.Prompt prompt = prompts.get(0);
     assertEquals("prompt1_name", prompt.name());
     assertEquals("prompt1_title", prompt.title());
     assertEquals("prompt1_description", prompt.description());
-    assertTrue(prompt.arguments().isEmpty());
+
+    List<McpSchema.PromptArgument> arguments = prompt.arguments();
+    assertEquals(2, arguments.size());
+    assertEquals("param1", arguments.get(0).name());
+    assertEquals("param1_title", arguments.get(0).title());
+    assertEquals("param1_description", arguments.get(0).description());
+    assertEquals("param2", arguments.get(1).name());
+    assertEquals("param2_title", arguments.get(1).title());
+    assertEquals("param2_description", arguments.get(1).description());
+  }
+
+  private void verifyPromptsCalled(McpSyncClient client) {
+    String name1 = "prompt1_name";
+    Map<String, Object> args1 = Map.of("param1", "value1", "param2", "value2");
+    McpSchema.GetPromptRequest request1 = new McpSchema.GetPromptRequest(name1, args1);
+    McpSchema.GetPromptResult result1 = client.getPrompt(request1);
+    McpSchema.TextContent content = (McpSchema.TextContent) result1.messages().get(0).content();
+    assertEquals(ObjectMappers.toJson(args1), content.text());
+    assertEquals("prompt1_description", result1.description());
   }
 
   private void verifyToolsRegistered(McpSyncClient client) {

src/test/java/com/github/codeboyzhou/mcp/declarative/test/TestMcpPrompts.java

@@ -1,11 +1,18 @@
 package com.github.codeboyzhou.mcp.declarative.test;
 
 import com.github.codeboyzhou.mcp.declarative.annotation.McpPrompt;
+import com.github.codeboyzhou.mcp.declarative.annotation.McpPromptParam;
+import com.github.codeboyzhou.mcp.declarative.util.ObjectMappers;
+import java.util.Map;
 
 public class TestMcpPrompts {
 
   @McpPrompt(name = "prompt1_name", title = "prompt1_title", description = "prompt1_description")
-  public String prompt1() {
-    return "prompt1_content";
+  public String prompt1(
+      @McpPromptParam(name = "param1", title = "param1_title", description = "param1_description")
+          String param1,
+      @McpPromptParam(name = "param2", title = "param2_title", description = "param2_description")
+          String param2) {
+    return ObjectMappers.toJson(Map.of("param1", param1, "param2", param2));
   }
 }