Merge pull request #50320 from phillip-kruger/dev-mcp-params-issue

Dev MCP: Don't set empty params

Author: phillip-kruger

extensions/devui/deployment/src/test/java/io/quarkus/devui/devmcp/DevMcpTest.java

@@ -175,6 +175,36 @@ public void testToolsCall() {
 
     }
 
+    @Test
+    public void testToolsCallWithEmptyArgs() {
+        String jsonBody = """
+                    {
+                      "jsonrpc": "2.0",
+                      "id": 4,
+                      "method": "tools/call",
+                      "params": {
+                        "name": "devui-logstream_getLoggers",
+                        "arguments": {}
+                      }
+                    }
+                """;
+
+        RestAssured
+                .given()
+                .contentType(ContentType.JSON)
+                .body(jsonBody)
+                .when()
+                .post("/q/dev-mcp")
+                .then()
+                .statusCode(200)
+                .log().all()
+                .body("id", CoreMatchers.equalTo(4))
+                .body("jsonrpc", CoreMatchers.equalTo("2.0"))
+                .body("result.content.type", CoreMatchers.hasItem("text"))
+                .body("result.content.text", CoreMatchers.notNullValue());
+
+    }
+
     @Test
     public void testResourcesList() {
         String jsonBody = """

extensions/devui/runtime/src/main/java/io/quarkus/devui/runtime/jsonrpc/JsonRpcRequestCreator.java

@@ -55,7 +55,8 @@ private JsonRpcRequest remap(JsonRpcRequest jsonRpcRequest) {
             mapped.setId(jsonRpcRequest.getId());
             mapped.setJsonrpc(jsonRpcRequest.getJsonrpc());
             mapped.setMethod(mappedName);
-            mapped.setParams(mappedParams);
+            if (mappedParams != null && !mappedParams.isEmpty())
+                mapped.setParams(mappedParams);
 
             return mapped;
         }

extensions/devui/runtime/src/main/java/io/quarkus/devui/runtime/mcp/McpHttpHandler.java

@@ -110,9 +110,17 @@ private void handleMCPJsonRPCRequest(RoutingContext ctx) {
                 // This is a MCP notification
                 this.routeToMCPNotification(jsonRpcRequest, codec, writer);
             } else if (methodName.equalsIgnoreCase(McpBuiltinMethods.TOOLS_LIST) ||
-                    methodName.equalsIgnoreCase(McpBuiltinMethods.RESOURCES_LIST) ||
-                    methodName.equalsIgnoreCase(McpBuiltinMethods.RESOURCES_READ)) {
+                    methodName.equalsIgnoreCase(McpBuiltinMethods.RESOURCES_LIST)) {
                 jsonRpcRequest.setMethod(methodName.replace(SLASH, UNDERSCORE));
+                // Make sure that parameters is empty as expected.
+                jsonRpcRequest.setParams(null);
+                jsonRpcRouter.route(jsonRpcRequest, writer);
+            } else if (methodName.equalsIgnoreCase(McpBuiltinMethods.RESOURCES_READ)) {
+                jsonRpcRequest.setMethod(methodName.replace(SLASH, UNDERSCORE));
+                // Make sure that the only parameter is uri (as expected).
+                String uri = jsonRpcRequest.getParam("uri", String.class);
+                jsonRpcRequest.getParams().clear();
+                jsonRpcRequest.setParams(Map.of("uri", uri));
                 jsonRpcRouter.route(jsonRpcRequest, writer);
             } else {
                 // This is a normal extension method