MCP: improve ChatGPT compatibility

Author: drhelius

platforms/shared/desktop/mcp/mcp_debug_adapter.cpp

@@ -170,7 +170,7 @@ std::vector<BreakpointInfo> DebugAdapter::ListBreakpoints()
     HuC6280* cpu = m_core->GetHuC6280();
     std::vector<HuC6280::GG_Breakpoint>* breakpoints = cpu->GetBreakpoints();
 
-    for (const auto& brk : *breakpoints)
+    for (const HuC6280::GG_Breakpoint& brk : *breakpoints)
     {
         BreakpointInfo info;
         info.enabled = brk.enabled;

platforms/shared/desktop/mcp/mcp_manager.h

@@ -65,6 +65,9 @@ class McpManager
         if (m_server && m_server->IsRunning())
             return;
 
+        m_commandQueue.Clear();
+        m_responseQueue.Reset();
+
         McpTransportInterface* transport = NULL;
         if (m_transport_mode == MCP_TRANSPORT_TCP)
         {

platforms/shared/desktop/mcp/mcp_server.cpp

@@ -54,11 +54,12 @@ void McpServer::ReaderLoop()
 
 void McpServer::Run()
 {
-    // Start reader thread for stdin
+    // Start reader thread for transport input
     std::thread reader_thread(ReaderThreadFunc, this);
     reader_thread.detach();
 
-    // Main loop: wait for responses and send them
+    // Transport thread waits for responses generated by the main thread
+    // (via PumpCommands) and sends them back through the transport
     while (m_running.load())
     {
         DebugResponse* resp = m_responseQueue.WaitAndPop();
@@ -144,7 +145,11 @@ void McpServer::HandleLine(const std::string& line)
     }
     else if (method == "notifications/initialized")
     {
-        // No response required for notifications
+        // Notifications don't need JSON-RPC response, but HTTP needs HTTP response
+        if (dynamic_cast<HttpTransport*>(m_transport))
+        {
+            m_transport->send("{}");
+        }
     }
     else if (method == "tools/list")
     {
@@ -1874,7 +1879,7 @@ void McpServer::LoadResourcesFromCategory(const std::string& category, const std
     // Get the directory containing toc.json
     std::string tocDir = tocPath.substr(0, tocPath.find_last_of("/\\"));
 
-    for (const auto& item : toc["toc"])
+    for (const json& item : toc["toc"])
     {
         if (!item.contains("uri") || !item.contains("title"))
             continue;
@@ -1918,7 +1923,7 @@ void McpServer::HandleResourcesList(const json& request)
 
     json resources = json::array();
 
-    for (const auto& resource : m_resources)
+    for (const ResourceInfo& resource : m_resources)
     {
         json resourceJson;
         resourceJson["uri"] = resource.uri;
@@ -1958,7 +1963,7 @@ void McpServer::HandleResourcesRead(const json& request)
     std::string uri = request["params"]["uri"];
 
     // Find resource
-    auto it = m_resourceMap.find(uri);
+    std::map<std::string, ResourceInfo>::const_iterator it = m_resourceMap.find(uri);
     if (it == m_resourceMap.end())
     {
         SendError(id, -32602, "Resource not found: " + uri);

platforms/shared/desktop/mcp/mcp_server.h

@@ -79,6 +79,16 @@ class CommandQueue
         return cmd;
     }
 
+    void Clear()
+    {
+        std::lock_guard<std::mutex> lock(m_mutex);
+        while (!m_queue.empty())
+        {
+            SafeDelete(m_queue.front());
+            m_queue.pop();
+        }
+    }
+
 private:
     std::queue<DebugCommand*> m_queue;
     std::mutex m_mutex;
@@ -114,6 +124,17 @@ class ResponseQueue
         m_cv.notify_all();
     }
 
+    void Reset()
+    {
+        std::lock_guard<std::mutex> lock(m_mutex);
+        while (!m_queue.empty())
+        {
+            SafeDelete(m_queue.front());
+            m_queue.pop();
+        }
+        m_running = true;
+    }
+
 private:
     std::queue<DebugResponse*> m_queue;
     std::mutex m_mutex;

platforms/shared/desktop/mcp/mcp_transport.h

@@ -25,6 +25,7 @@
 #include <string>
 #include <iostream>
 #include <mutex>
+#include <condition_variable>
 #include <cerrno>
 #include "log.h"
 
@@ -178,6 +179,7 @@ class HttpTransport : public McpTransportInterface
             Error("[MCP] HTTP send() failed: %d", sent);
             SOCKET_CLOSE(m_current_client);
             m_current_client = INVALID_SOCKET_VALUE;
+            m_client_cv.notify_all();
             return false;
         }
 
@@ -190,6 +192,7 @@ class HttpTransport : public McpTransportInterface
         // Close connection after response (VS Code will reconnect for next request)
         SOCKET_CLOSE(m_current_client);
         m_current_client = INVALID_SOCKET_VALUE;
+        m_client_cv.notify_all();
 
         return true;
     }
@@ -232,6 +235,7 @@ class HttpTransport : public McpTransportInterface
         {
             std::lock_guard<std::mutex> lock(m_mutex);
             m_current_client = INVALID_SOCKET_VALUE;
+            m_client_cv.notify_all();
         }
         return false;
     }
@@ -240,7 +244,22 @@ class HttpTransport : public McpTransportInterface
     {
         while (!m_closed && m_server_socket != INVALID_SOCKET_VALUE)
         {
-            // Always accept new connection (we close after each response)
+            // Wait until any previous client has been responded to and closed
+            {
+                std::unique_lock<std::mutex> lock(m_mutex);
+                m_client_cv.wait(lock, [this]
+                {
+                    return m_closed || m_current_client == INVALID_SOCKET_VALUE;
+                });
+
+                if (m_closed)
+                {
+                    Debug("[MCP] Server closed, stopping recv loop");
+                    return false;
+                }
+            }
+
+            // Accept new connection (we close after each response)
             struct sockaddr_in client_addr;
             socklen_t client_len = sizeof(client_addr);
             socket_t client = accept(m_server_socket, (struct sockaddr*)&client_addr, &client_len);
@@ -346,6 +365,7 @@ class HttpTransport : public McpTransportInterface
                 std::lock_guard<std::mutex> lock(m_mutex);
                 SOCKET_CLOSE(m_current_client);
                 m_current_client = INVALID_SOCKET_VALUE;
+                m_client_cv.notify_all();
                 continue; // Wait for next connection
             }
 
@@ -367,6 +387,7 @@ class HttpTransport : public McpTransportInterface
                 std::lock_guard<std::mutex> lock(m_mutex);
                 SOCKET_CLOSE(m_current_client);
                 m_current_client = INVALID_SOCKET_VALUE;
+                m_client_cv.notify_all();
                 continue; // Wait for next connection
             }
 
@@ -406,6 +427,7 @@ class HttpTransport : public McpTransportInterface
                 std::lock_guard<std::mutex> lock(m_mutex);
                 SOCKET_CLOSE(m_current_client);
                 m_current_client = INVALID_SOCKET_VALUE;
+                m_client_cv.notify_all();
                 continue; // Wait for next request
             }
 
@@ -421,6 +443,7 @@ class HttpTransport : public McpTransportInterface
                 std::lock_guard<std::mutex> lock(m_mutex);
                 SOCKET_CLOSE(m_current_client);
                 m_current_client = INVALID_SOCKET_VALUE;
+                m_client_cv.notify_all();
                 continue; // Wait for next request
             }
 
@@ -439,6 +462,7 @@ class HttpTransport : public McpTransportInterface
                 std::lock_guard<std::mutex> lock(m_mutex);
                 SOCKET_CLOSE(m_current_client);
                 m_current_client = INVALID_SOCKET_VALUE;
+                m_client_cv.notify_all();
                 continue; // Wait for next connection
             }
         }
@@ -449,6 +473,7 @@ class HttpTransport : public McpTransportInterface
     void close()
     {
         m_closed = true;
+        m_client_cv.notify_all();
 
         if (m_current_client != INVALID_SOCKET_VALUE)
         {
@@ -465,6 +490,7 @@ class HttpTransport : public McpTransportInterface
 
 private:
     std::mutex m_mutex;
+    std::condition_variable m_client_cv;
     bool m_closed;
     socket_t m_server_socket;
     socket_t m_current_client;