fix: restore MCP servers and skills when recreating expired session

PolyPilot.Tests/ConnectionRecoveryTests.cs

@@ -264,6 +264,88 @@ public void SendPromptAsync_ReconnectPath_UsesRefreshedClientForCreateSession()
             "client.CreateSessionAsync (Session not found fallback) must be after client = _client refresh");
     }
 
+    // ===== Regression: Fresh session after "Session not found" must include MCP servers & skills =====
+    // When the JSON-RPC connection is lost and the server-side session has expired,
+    // SendPromptAsync falls back to creating a fresh session via CreateSessionAsync.
+    // Previously, the freshConfig was missing McpServers, SkillDirectories, and
+    // SystemMessage — causing "environment keeps going away" because MCP tools
+    // disappeared after reconnection.
+
+    [Fact]
+    public void SendPromptAsync_FreshSessionConfig_IncludesMcpServers()
+    {
+        // STRUCTURAL REGRESSION GUARD: The "Session not found" fallback must assign
+        // McpServers in the freshConfig so MCP tools survive reconnection.
+        var source = File.ReadAllText(Path.Combine(GetRepoRoot(), "PolyPilot", "Services", "CopilotService.cs"));
+
+        // Anchor on the freshConfig initializer inside the "Session not found" reconnect path
+        var freshConfigIndex = source.IndexOf("freshConfig = new SessionConfig");
+        Assert.True(freshConfigIndex > 0, "Could not find freshConfig in reconnect path");
+
+        // Extract the config block (generously sized to cover all fields)
+        var endIndex = Math.Min(freshConfigIndex + 600, source.Length);
+        var configBlock = source.Substring(freshConfigIndex, endIndex - freshConfigIndex);
+        Assert.Contains("McpServers = ", configBlock);
+    }
+
+    [Fact]
+    public void SendPromptAsync_FreshSessionConfig_IncludesSkillDirectories()
+    {
+        // STRUCTURAL REGRESSION GUARD: The "Session not found" fallback must assign
+        // SkillDirectories in the freshConfig so skills survive reconnection.
+        var source = File.ReadAllText(Path.Combine(GetRepoRoot(), "PolyPilot", "Services", "CopilotService.cs"));
+
+        var freshConfigIndex = source.IndexOf("freshConfig = new SessionConfig");
+        Assert.True(freshConfigIndex > 0, "Could not find freshConfig in reconnect path");
+
+        var endIndex = Math.Min(freshConfigIndex + 600, source.Length);
+        var configBlock = source.Substring(freshConfigIndex, endIndex - freshConfigIndex);
+        Assert.Contains("SkillDirectories = ", configBlock);
+    }
+
+    [Fact]
+    public void SendPromptAsync_FreshSessionConfig_IncludesSystemMessage()
+    {
+        // STRUCTURAL REGRESSION GUARD: The "Session not found" fallback must include
+        // SystemMessage so the session retains its system prompt after reconnection.
+        var source = File.ReadAllText(Path.Combine(GetRepoRoot(), "PolyPilot", "Services", "CopilotService.cs"));
+
+        var freshConfigIndex = source.IndexOf("freshConfig = new SessionConfig");
+        Assert.True(freshConfigIndex > 0, "Could not find freshConfig in reconnect path");
+
+        var endIndex = Math.Min(freshConfigIndex + 600, source.Length);
+        var configBlock = source.Substring(freshConfigIndex, endIndex - freshConfigIndex);
+        Assert.Contains("SystemMessage = ", configBlock);
+        Assert.Contains("SystemMessageMode.Append", configBlock);
+    }
+
+    [Fact]
+    public void SendPromptAsync_FreshSessionConfig_MatchesCreateSessionFields()
+    {
+        // STRUCTURAL REGRESSION GUARD: The freshConfig in the reconnect path must
+        // set the same critical fields as the original CreateSessionAsync config.
+        // This prevents "environment keeps going away" after connection loss.
+        var source = File.ReadAllText(Path.Combine(GetRepoRoot(), "PolyPilot", "Services", "CopilotService.cs"));
+
+        var freshConfigIndex = source.IndexOf("freshConfig = new SessionConfig");
+        Assert.True(freshConfigIndex > 0);
+
+        // Extract the full config initializer block
+        var endIndex = Math.Min(freshConfigIndex + 800, source.Length);
+        var configBlock = source.Substring(freshConfigIndex, endIndex - freshConfigIndex);
+
+        // All critical SessionConfig property assignments must be present
+        var requiredAssignments = new[]
+        {
+            "Model = ", "WorkingDirectory = ", "McpServers = ", "SkillDirectories = ",
+            "Tools = ", "SystemMessage = ", "OnPermissionRequest = "
+        };
+        foreach (var assignment in requiredAssignments)
+        {
+            Assert.Contains(assignment, configBlock);
+        }
+    }
+
     [Fact]
     public void IsConnectionError_DetectsOrchestratorDispatchError()
     {

PolyPilot/Services/CopilotService.cs

@@ -2446,16 +2446,50 @@ public async Task<string> SendPromptAsync(string sessionName, string prompt, Lis
                     }
                     catch (Exception resumeEx) when (resumeEx.Message.Contains("Session not found", StringComparison.OrdinalIgnoreCase))
                     {
-                        // Session expired server-side (e.g., codespace restarted). Create a fresh session.
+                        // Session expired server-side (e.g., codespace restarted). Create a fresh session
+                        // with full config (MCP servers, skills, system message) matching CreateSessionAsync.
                         Debug($"Session '{sessionName}' expired on server, creating fresh session...");
                         OnActivity?.Invoke(sessionName, "🔄 Session expired, creating new session...");
+                        var freshSettings = _currentSettings ?? ConnectionSettings.Load();
+                        var freshMcpServers = LoadMcpServers(freshSettings.DisabledMcpServers, freshSettings.DisabledPlugins);
+                        var freshSkillDirs = LoadSkillDirectories(freshSettings.DisabledPlugins);
+                        // Rebuild system message with the same conditional logic as CreateSessionAsync
+                        var freshSystemContent = new StringBuilder();
+                        var freshDir = state.Info.WorkingDirectory;
+                        if (string.Equals(freshDir, ProjectDir, StringComparison.OrdinalIgnoreCase))
+                        {
+                            var relaunchCmd = OperatingSystem.IsWindows()
+                                ? $"powershell -ExecutionPolicy Bypass -File \"{Path.Combine(ProjectDir, "relaunch.ps1")}\""
+                                : $"bash {Path.Combine(ProjectDir, "relaunch.sh")}";
+                            freshSystemContent.AppendLine($@"
+CRITICAL BUILD INSTRUCTION: You are running inside the PolyPilot MAUI application.
+When you make ANY code changes to files in {ProjectDir}, you MUST rebuild and relaunch by running:
+
+    {relaunchCmd}
+
+This script builds the app, launches a new instance, waits for it to start, then kills the old one.
+NEVER use 'dotnet build' + 'open' separately. NEVER skip the relaunch after code changes.
+ALWAYS run the relaunch script as the final step after making changes to this project.
+");
+                        }
                         var freshConfig = new SessionConfig
                         {
                             Model = reconnectModel ?? DefaultModel,
-                            WorkingDirectory = state.Info.WorkingDirectory,
+                            WorkingDirectory = freshDir,
+                            McpServers = freshMcpServers,
+                            SkillDirectories = freshSkillDirs,
                             Tools = new List<Microsoft.Extensions.AI.AIFunction> { ShowImageTool.CreateFunction() },
+                            SystemMessage = new SystemMessageConfig
+                            {
+                                Mode = SystemMessageMode.Append,
+                                Content = freshSystemContent.ToString()
+                            },
                             OnPermissionRequest = AutoApprovePermissions
                         };
+                        if (freshMcpServers != null)
+                            Debug($"[RECONNECT] Fresh session config includes {freshMcpServers.Count} MCP server(s)");
+                        if (freshSkillDirs != null)
+                            Debug($"[RECONNECT] Fresh session config includes {freshSkillDirs.Count} skill dir(s)");
                         newSession = await client.CreateSessionAsync(freshConfig, cancellationToken);
                         state.Info.SessionId = newSession.SessionId;
                     }