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Merged
DearVa merged 3 commits into from
Apr 11, 2026
Merged

refactor: extract ManagedMcpClient and handle session expiry (#232) #338

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ae2bc0f
refactor: extract ManagedMcpClient and handle session expiry (#232)
TheNotoBarth Apr 11, 2026
68eaa56
refactor: cleanup code & handle potential task exceptions
DearVa Apr 11, 2026
5a9426c
refactor: introduce concurrent managed MCP client management
DearVa Apr 11, 2026
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20 changes: 3 additions & 17 deletions src/Everywhere.Core/Chat/Plugins/ChatFunction.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,9 +2,9 @@
using System.Reflection;
using CommunityToolkit.Mvvm.ComponentModel;
using Everywhere.Chat.Permissions;
using Everywhere.Chat.Plugins.Mcp;
using Lucide.Avalonia;
using Microsoft.SemanticKernel;
using ModelContextProtocol.Client;
using ZLinq;

namespace Everywhere.Chat.Plugins;
Expand Down Expand Up @@ -128,29 +128,15 @@ public NativeChatFunction(
}
}

public sealed class McpChatFunction : ChatFunction
public class McpChatFunction : ChatFunction
{
public override ChatFunctionPermissions Permissions => ChatFunctionPermissions.MCP;

public override KernelFunction KernelFunction { get; }

public McpChatFunction(McpClientTool tool)
public McpChatFunction(ManagedMcpClientTool tool)
{
KernelFunction = tool.AsKernelFunction();
IsAutoApproveAllowed = true;
}

/// <summary>
/// MCP tool name SHOULD only allow: uppercase and lowercase ASCII letters (A-Z, a-z), digits (0-9), underscore (_), hyphen (-), and dot (.)
/// But SK only allow ASCII letters, digits, and underscores in function name, so we need to escape the tool name to make it compatible with SK.
/// </summary>
/// <param name="tool"></param>
private static void EscapeToolName(McpClientTool tool)
{
ref var name = ref GetName(tool);
name = new string(name.AsValueEnumerable().Select(c => char.IsLetterOrDigit(c) ? c : '_').ToArray());
}

[UnsafeAccessor(UnsafeAccessorKind.Field, Name = "_name")]
private static extern ref string GetName(McpClientTool tool);
}
196 changes: 10 additions & 186 deletions src/Everywhere.Core/Chat/Plugins/ChatPluginManager.cs
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Original file line number Diff line number Diff line change
@@ -1,21 +1,18 @@
using System.Collections.Concurrent;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Reactive.Disposables;
using System.Text;
using DynamicData;
using Everywhere.Chat.Permissions;
using Everywhere.Chat.Plugins.Mcp;
using Everywhere.Collections;
using Everywhere.Common;
using Everywhere.Configuration;
using Everywhere.Initialization;
using Everywhere.Interop;
using Everywhere.Utilities;
using FuzzySharp;
using Lucide.Avalonia;
using Microsoft.Extensions.Logging;
using ModelContextProtocol.Client;
using ModelContextProtocol.Protocol;
using ZLinq;

namespace Everywhere.Chat.Plugins;
Expand All @@ -30,12 +27,11 @@ public class ChatPluginManager : IChatPluginManager
private readonly IHttpClientFactory _httpClientFactory;
private readonly ILoggerFactory _loggerFactory;
private readonly Settings _settings;
private readonly ILogger<ChatPluginManager> _logger;

private readonly CompositeDisposable _disposables = new();
private readonly SourceList<BuiltInChatPlugin> _builtInPluginsSource = new();
private readonly SourceList<McpChatPlugin> _mcpPluginsSource = new();
private readonly ConcurrentDictionary<Guid, McpClient> _runningMcpClients = [];
private readonly ConcurrentDictionary<Guid, ManagedMcpClient> _startedMcpClients = [];

public ChatPluginManager(
IEnumerable<BuiltInChatPlugin> builtInPlugins,
Expand All @@ -49,7 +45,6 @@ public ChatPluginManager(
_httpClientFactory = httpClientFactory;
_loggerFactory = loggerFactory;
_settings = settings;
_logger = loggerFactory.CreateLogger<ChatPluginManager>();

// Load MCP plugins from settings.
_mcpPluginsSource.AddRange(settings.Plugin.McpChatPlugins.Select(m => m.ToMcpChatPlugin()).OfType<McpChatPlugin>());
Expand Down Expand Up @@ -217,10 +212,9 @@ public async Task UpdateMcpPluginAsync(McpChatPlugin mcpChatPlugin, McpTransport

public async Task StopMcpClientAsync(McpChatPlugin mcpChatPlugin)
{
if (_runningMcpClients.TryRemove(mcpChatPlugin.Id, out var runningClient))
if (_startedMcpClients.TryRemove(mcpChatPlugin.Id, out var runningClient))
{
await runningClient.DisposeAsync();
mcpChatPlugin.IsRunning = false;
}
}

Expand All @@ -246,104 +240,10 @@ public async Task StartMcpClientAsync(McpChatPlugin mcpChatPlugin, CancellationT
new DynamicResourceKey(LocaleKey.ChatPluginManager_Common_InvalidMcpTransportConfiguration));
}

if (_runningMcpClients.ContainsKey(mcpChatPlugin.Id)) return; // Just return without error if already running.

var loggerFactory = new McpLoggerFactory(mcpChatPlugin, _loggerFactory);
IClientTransport clientTransport = transportConfiguration switch
{
StdioMcpTransportConfiguration stdio => new StdioClientTransport(
new StdioClientTransportOptions
{
Name = stdio.Name,
Command = stdio.Command,
Arguments = stdio.Arguments
.AsValueEnumerable()
.Select(x => x.Value)
.Where(x => !x.IsNullOrWhiteSpace())
.ToList(),
WorkingDirectory = EnsureWorkingDirectory(stdio.WorkingDirectory),
EnvironmentVariables = EnsureLatestPath(
stdio.EnvironmentVariables
.AsValueEnumerable()
.Where(kv => !kv.Key.IsNullOrWhiteSpace())
.DistinctBy(
kv => kv.Key,
OperatingSystem.IsWindows() ? StringComparer.OrdinalIgnoreCase : StringComparer.Ordinal)
.ToDictionary(
kv => kv.Key,
kv => kv.Value,
OperatingSystem.IsWindows() ? StringComparer.OrdinalIgnoreCase : StringComparer.Ordinal)),
},
loggerFactory),
HttpMcpTransportConfiguration sse => new HttpClientTransport(
new HttpClientTransportOptions
{
Name = sse.Name,
Endpoint = new Uri(sse.Endpoint, UriKind.Absolute),
AdditionalHeaders = sse.Headers
.AsValueEnumerable()
.Where(kv => !kv.Key.IsNullOrWhiteSpace() && !kv.Value.IsNullOrWhiteSpace())
.DistinctBy(kv => kv.Key)
.ToDictionary(kv => kv.Key, kv => kv.Value),
TransportMode = sse.TransportMode
},
_httpClientFactory.CreateClient(NetworkExtension.JsonRpcClientName),
loggerFactory),
_ =>
throw new HandledException(
new InvalidOperationException("Unsupported MCP transport configuration type."),
new DynamicResourceKey(LocaleKey.ChatPluginManager_Common_InvalidMcpTransportConfiguration))
};

var client = await McpClient.CreateAsync(
clientTransport,
null,
loggerFactory,
cancellationToken);

// Store the running client.
_runningMcpClients[mcpChatPlugin.Id] = client;
mcpChatPlugin.IsRunning = true;

var processId = -1;
try
{
if (clientTransport is StdioClientTransport)
{
// Add the underlying process to the watchdog to ensure it is cleaned up properly.
// We need reflection here because StdioClientTransport does not expose the process directly.
// client is `ModelContextProtocol.Client.McpClientImpl`
var transport = GetMcpClientTransport(client);
if (GetStdioClientSessionTransportProcess(transport) is { HasExited: false, Id: > 0 } process)
{
process.Exited += HandleProcessExited;

void HandleProcessExited(object? sender, EventArgs e)
{
mcpChatPlugin.IsRunning = false;
_runningMcpClients.TryRemove(mcpChatPlugin.Id, out _);
process.Exited -= HandleProcessExited;
}

await _watchdogManager.RegisterProcessAsync(process.Id);
processId = process.Id;
}
}
}
finally
{
if (processId == -1 && transportConfiguration is StdioMcpTransportConfiguration stdio)
{
_logger.LogWarning(
"MCP started with stdio transport, but failed to get the underlying process ID for watchdog registration. " +
"Command: {Command}, Arguments: {Arguments}",
stdio.Command,
stdio.Arguments);
}
}

var tools = await client.ListToolsAsync(cancellationToken: cancellationToken);
var client = await ManagedMcpClient.StartAsync(mcpChatPlugin, _httpClientFactory, _watchdogManager, _loggerFactory, cancellationToken);
_startedMcpClients[mcpChatPlugin.Id] = client;

var tools = await client.ListToolsAsync(cancellationToken);
var isEnabledRecords = _settings.Plugin.IsEnabledRecords;
var isPermissionGrantedRecords = _settings.Plugin.IsPermissionGrantedRecords;
mcpChatPlugin.SetFunctions(
Expand All @@ -352,33 +252,6 @@ void HandleProcessExited(object? sender, EventArgs e)
IsEnabled = !isEnabledRecords.TryGetValue(t.Name, out var isEnabled) || isEnabled, // true if not set
AutoApprove = isPermissionGrantedRecords.TryGetValue(t.Name, out var isGranted) && isGranted, // false if not set
}));

string EnsureWorkingDirectory(string? workingDirectory)
{
if (Directory.Exists(workingDirectory)) return workingDirectory;

// If not exists, fall back to Everywhere\cache\plugins\mcp\<plugin-id>
var fallbackDir = RuntimeConstants.EnsureWritableDataFolderPath("plugins", "mcp", mcpChatPlugin.Id.ToString("N"));
return fallbackDir;
}

Dictionary<string, string?> EnsureLatestPath(Dictionary<string, string?> environmentVariables)
{
var latestPath = EnvironmentVariableUtilities.GetLatestPathVariable();
if (latestPath.IsNullOrEmpty()) return environmentVariables;

// Put our latest PATH at the front.
var pathBuilder = new StringBuilder(latestPath);

// Append existing PATH variable if any.
if (environmentVariables.TryGetValue("PATH", out var existingPath) && !existingPath.IsNullOrEmpty())
{
pathBuilder.Append(Path.PathSeparator).Append(existingPath);
}

environmentVariables["PATH"] = pathBuilder.ToString();
return environmentVariables;
}
}

public async Task<IChatPluginScope> CreateScopeAsync(bool isSubagent, CancellationToken cancellationToken)
Expand Down Expand Up @@ -419,14 +292,6 @@ public async Task<IChatPluginScope> CreateScopeAsync(bool isSubagent, Cancellati
.ToList());
}

[UnsafeAccessor(UnsafeAccessorKind.Field, Name = "_transport")]
private static extern ref ITransport GetMcpClientTransport(
[UnsafeAccessorType("ModelContextProtocol.Client.McpClientImpl, ModelContextProtocol.Core")] object client);

[UnsafeAccessor(UnsafeAccessorKind.Field, Name = "_process")]
private static extern ref Process GetStdioClientSessionTransportProcess(
[UnsafeAccessorType("ModelContextProtocol.Client.StdioClientSessionTransport, ModelContextProtocol.Core")] object transport);

private class ChatPluginScope(List<ChatPluginSnapshot> pluginSnapshots) : IChatPluginScope
{
public IReadOnlyList<ChatPlugin> Plugins => pluginSnapshots;
Expand All @@ -450,7 +315,7 @@ public bool TryGetPluginAndFunction(

plugin = null;
function = null;
similarFunctionNames = FuzzySharp.Process.ExtractTop(
similarFunctionNames = Process.ExtractTop(
functionName,
pluginSnapshots.SelectMany(p => p.Functions).Select(f => f.KernelFunction.Name),
limit: 5)
Expand Down Expand Up @@ -504,11 +369,11 @@ ChatFunction EnsureUniqueFunctionName(ChatFunction function)

public void Dispose()
{
foreach (var mcpClient in _runningMcpClients.Values)
foreach (var mcpClient in _startedMcpClients.Values)
{
mcpClient.DisposeAsync().Detach(IExceptionHandler.DangerouslyIgnoreAllException);
}
_runningMcpClients.Clear();
_startedMcpClients.Clear();

_mcpPluginsSource.Edit(items =>
{
Expand All @@ -519,45 +384,4 @@ public void Dispose()
});
_disposables.Dispose();
}

/// <summary>
/// Used to create ILogger instances for MCP clients.
/// It logs to both the Everywhere logging system and the <see cref="McpChatPlugin"/>'s log entries.
/// </summary>
private sealed class McpLoggerFactory(McpChatPlugin mcpChatPlugin, ILoggerFactory innerLoggerFactory) : ILoggerFactory
{
public void AddProvider(ILoggerProvider provider)
{
innerLoggerFactory.AddProvider(provider);
}

public ILogger CreateLogger(string categoryName)
{
var innerLogger = innerLoggerFactory.CreateLogger(categoryName);
return new McpLogger(mcpChatPlugin, innerLogger);
}

public void Dispose()
{
innerLoggerFactory.Dispose();
}

private sealed class McpLogger(ILogger mcpChatPlugin, ILogger innerLogger) : ILogger
{
public IDisposable? BeginScope<TState>(TState state) where TState : notnull => innerLogger.BeginScope(state);

public bool IsEnabled(LogLevel logLevel) => true;

public void Log<TState>(
LogLevel logLevel,
EventId eventId,
TState state,
Exception? exception,
Func<TState, Exception?, string> formatter)
{
mcpChatPlugin.Log(logLevel, eventId, state, exception, formatter);
innerLogger.Log(logLevel, eventId, state, exception, formatter);
}
}
}
}
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