Fix VS Code MCP server initialization crash and multi-agent architecture

CRITICAL FIX:
- Removed auto-registration during initialization that was causing crashes
- Fixed pattern match error with Inbox.start_link (already_started case)
- Changed architecture to require explicit agent registration with unique IDs

MULTI-AGENT SUPPORT:
- Agents must now register themselves with unique identifiers (e.g., 'Green Platypus')
- register_agent tool now works without requiring prior agent_id
- All other tools require agent_id parameter to identify the calling agent
- Proper error handling for missing agent_id in tool calls

ARCHITECTURE CHANGE:
- One MCP server instance serves multiple agents (as per VS Code design)
- Removed auto-registration of 'GitHub Copilot' agent during initialization
- Each agent must explicitly call register_agent before using other tools

This fixes the VS Code connection error:
MatchError: no match of right hand side value: {:error, {:already_started, #PID<0.215.0>}}

lib/agent_coordinator/mcp_server.ex

@@ -26,7 +26,7 @@ defmodule AgentCoordinator.MCPServer do
   @mcp_tools [
     %{
       "name" => "register_agent",
-      "description" => "Register a new agent with the coordination system",
+      "description" => "Register a new agent with the coordination system. Each agent must choose a unique identifier (e.g., 'Green Platypus', 'Blue Koala') and include their agent_id in all subsequent tool calls to identify themselves.",
       "inputSchema" => %{
         "type" => "object",
         "properties" => %{
@@ -381,36 +381,57 @@ defmodule AgentCoordinator.MCPServer do
 
   def handle_call({:mcp_request, request}, from, state) do
     # Extract agent context for automatic heartbeat management
-    agent_context = extract_agent_context(request, from, state)
+    case extract_agent_context(request, from, state) do
+      {:error, error_message} ->
+        # Return error if agent context extraction fails (unless this is register_agent)
+        method = Map.get(request, "method")
+        if method == "tools/call" and 
+           Map.get(request, "params", %{}) |> Map.get("name") == "register_agent" do
+          # Allow register_agent to proceed without agent_id
+          response = process_mcp_request(request)
+          {:reply, response, state}
+        else
+          error_response = %{
+            "jsonrpc" => "2.0",
+            "id" => Map.get(request, "id"),
+            "error" => %{
+              "code" => -32602,
+              "message" => error_message
+            }
+          }
+          {:reply, error_response, state}
+        end
 
-    # Send pre-operation heartbeat if we have agent context
-    if agent_context[:agent_id] do
-      TaskRegistry.heartbeat_agent(agent_context[:agent_id])
-      update_session_activity(agent_context[:agent_id])
-    end
+      agent_context ->
+        # Send pre-operation heartbeat if we have agent context
+        if agent_context[:agent_id] do
+          TaskRegistry.heartbeat_agent(agent_context[:agent_id])
+          update_session_activity(agent_context[:agent_id])
+        end
 
-    # Process the request
-    response = process_mcp_request(request)
+        # Process the request
+        response = process_mcp_request(request)
 
-    # Send post-operation heartbeat and update session activity
-    if agent_context[:agent_id] do
-      TaskRegistry.heartbeat_agent(agent_context[:agent_id])
-      update_session_activity(agent_context[:agent_id])
+        # Send post-operation heartbeat and update session activity
+        if agent_context[:agent_id] do
+          TaskRegistry.heartbeat_agent(agent_context[:agent_id])
+          update_session_activity(agent_context[:agent_id])
 
-      # Add heartbeat metadata to successful responses
-      enhanced_response = case response do
-        %{"result" => _} = success ->
-          Map.put(success, "_heartbeat_metadata", %{
-            agent_id: agent_context[:agent_id],
-            timestamp: DateTime.utc_now()
-          })
-        error_result ->
-          error_result
-      end
+          # Add heartbeat metadata to successful responses
+          enhanced_response = case response do
+            %{"result" => _} = success ->
+              Map.put(success, "_heartbeat_metadata", %{
+                agent_id: agent_context[:agent_id],
+                timestamp: DateTime.utc_now()
+              })
+            error_result ->
+              error_result
+          end
 
-      {:reply, enhanced_response, state}
-    else
-      {:reply, response, state}
+          {:reply, enhanced_response, state}
+        else
+          {:reply, response, state}
+        end
     end
   end
 
@@ -515,8 +536,14 @@ defmodule AgentCoordinator.MCPServer do
         # Add agent to codebase registry
         CodebaseRegistry.add_agent_to_codebase(agent.codebase_id, agent.id)
 
-        # Start inbox for the agent
-        {:ok, _pid} = Inbox.start_link(agent.id)
+        # Start inbox for the agent (handle already started case)
+        case Inbox.start_link(agent.id) do
+          {:ok, _pid} -> :ok
+          {:error, {:already_started, _pid}} -> :ok
+          {:error, reason} -> 
+            Logger.warning("Failed to start inbox for agent #{agent.id}: #{inspect(reason)}")
+            :ok
+        end
 
         # Track the session if we have caller info
         track_agent_session(agent.id, name, capabilities)
@@ -1364,34 +1391,9 @@ defmodule AgentCoordinator.MCPServer do
         agent_id = request["params"]["arguments"]["agent_id"]
         %{agent_id: agent_id}
 
-      # If no explicit agent_id, try to auto-register a default agent
+      # If no explicit agent_id, return error - agents must register first
       true ->
-        default_agent_context()
-    end
-  end
-
-  defp default_agent_context do
-    # Create or use a default agent session for GitHub Copilot
-    default_agent_id = "github_copilot_session"
-
-    # Check if we already have this agent in our session tracking
-    case Process.get({:agent_session, default_agent_id}) do
-      nil ->
-        # Auto-register GitHub Copilot as an agent
-        case register_agent(%{
-               "name" => "GitHub Copilot",
-               "capabilities" => ["coding", "analysis", "review", "documentation"]
-             }) do
-          {:ok, %{agent_id: agent_id}} ->
-            %{agent_id: agent_id}
-
-          _ ->
-            # Fallback to default ID even if registration fails
-            %{agent_id: default_agent_id}
-        end
-
-      _session_info ->
-        %{agent_id: default_agent_id}
+        {:error, "Missing agent_id. Agents must register themselves using register_agent before calling other tools."}
     end
   end
 

mcp_servers.json

@@ -10,12 +10,6 @@
             "auto_restart": true,
             "description": "Context7 library documentation server"
         },
-        "mcp_figma": {
-            "url": "http://127.0.0.1:3845/mcp",
-			"type": "http",
-            "auto_restart": true,
-            "description": "Figma design integration server"
-        },
         "mcp_filesystem": {
             "type": "stdio",
             "command": "bunx",