diff --git a/src/ClaudeDo.Worker/Config/WorkerConfig.cs b/src/ClaudeDo.Worker/Config/WorkerConfig.cs
index 6ef4b0d..7f35b24 100644
--- a/src/ClaudeDo.Worker/Config/WorkerConfig.cs
+++ b/src/ClaudeDo.Worker/Config/WorkerConfig.cs
@@ -31,6 +31,14 @@ public sealed class WorkerConfig
     [JsonPropertyName("claude_bin")]
     public string ClaudeBin { get; set; } = "claude";
 
+    /// <summary>Port for the external MCP endpoint. 0 disables the external listener entirely.</summary>
+    [JsonPropertyName("external_mcp_port")]
+    public int ExternalMcpPort { get; set; } = 47_822;
+
+    /// <summary>Optional API key clients must pass via X-ClaudeDo-Key header. Null/empty = loopback trust only.</summary>
+    [JsonPropertyName("external_mcp_api_key")]
+    public string? ExternalMcpApiKey { get; set; }
+
     public static string DefaultConfigPath =>
         Path.Combine(Paths.AppDataRoot(), "worker.config.json");
 
diff --git a/src/ClaudeDo.Worker/External/ExternalMcpAuthMiddleware.cs b/src/ClaudeDo.Worker/External/ExternalMcpAuthMiddleware.cs
new file mode 100644
index 0000000..38b90ff
--- /dev/null
+++ b/src/ClaudeDo.Worker/External/ExternalMcpAuthMiddleware.cs
@@ -0,0 +1,32 @@
+using ClaudeDo.Worker.Config;
+using Microsoft.AspNetCore.Http;
+
+namespace ClaudeDo.Worker.External;
+
+public sealed class ExternalMcpAuthMiddleware
+{
+    private const string HeaderName = "X-ClaudeDo-Key";
+
+    private readonly RequestDelegate _next;
+
+    public ExternalMcpAuthMiddleware(RequestDelegate next) => _next = next;
+
+    public async Task InvokeAsync(HttpContext ctx, WorkerConfig cfg)
+    {
+        if (string.IsNullOrEmpty(cfg.ExternalMcpApiKey))
+        {
+            await _next(ctx);
+            return;
+        }
+
+        var provided = ctx.Request.Headers[HeaderName].ToString();
+        if (!string.Equals(provided, cfg.ExternalMcpApiKey, StringComparison.Ordinal))
+        {
+            ctx.Response.StatusCode = 401;
+            await ctx.Response.WriteAsync($"Missing or invalid {HeaderName} header");
+            return;
+        }
+
+        await _next(ctx);
+    }
+}
diff --git a/src/ClaudeDo.Worker/External/ExternalMcpService.cs b/src/ClaudeDo.Worker/External/ExternalMcpService.cs
new file mode 100644
index 0000000..bbe13ed
--- /dev/null
+++ b/src/ClaudeDo.Worker/External/ExternalMcpService.cs
@@ -0,0 +1,197 @@
+using System.ComponentModel;
+using ClaudeDo.Data.Models;
+using ClaudeDo.Data.Repositories;
+using ClaudeDo.Worker.Hub;
+using ClaudeDo.Worker.Services;
+using ModelContextProtocol.Server;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Worker.External;
+
+public sealed record TaskListDto(string Id, string Name, string? WorkingDir);
+
+public sealed record TaskDto(
+    string Id,
+    string ListId,
+    string Title,
+    string? Description,
+    string Status,
+    string? Result,
+    string? CreatedBy,
+    DateTime CreatedAt,
+    DateTime? StartedAt,
+    DateTime? FinishedAt);
+
+[McpServerToolType]
+public sealed class ExternalMcpService
+{
+    private readonly TaskRepository _tasks;
+    private readonly ListRepository _lists;
+    private readonly QueueService _queue;
+    private readonly HubBroadcaster _broadcaster;
+
+    public ExternalMcpService(
+        TaskRepository tasks,
+        ListRepository lists,
+        QueueService queue,
+        HubBroadcaster broadcaster)
+    {
+        _tasks = tasks;
+        _lists = lists;
+        _queue = queue;
+        _broadcaster = broadcaster;
+    }
+
+    [McpServerTool, Description("List all task lists available in ClaudeDo.")]
+    public async Task<IReadOnlyList<TaskListDto>> ListTaskLists(CancellationToken cancellationToken)
+    {
+        var lists = await _lists.GetAllAsync(cancellationToken);
+        return lists.Select(l => new TaskListDto(l.Id, l.Name, l.WorkingDir)).ToList();
+    }
+
+    [McpServerTool, Description("List tasks in a given list. Optionally filter by creator (CreatedBy) and/or status.")]
+    public async Task<IReadOnlyList<TaskDto>> ListTasks(
+        string listId,
+        string? createdBy,
+        string? status,
+        CancellationToken cancellationToken)
+    {
+        TaskStatus? statusFilter = null;
+        if (!string.IsNullOrWhiteSpace(status))
+        {
+            if (!Enum.TryParse<TaskStatus>(status, ignoreCase: true, out var parsed))
+                throw new InvalidOperationException($"Unknown status '{status}'.");
+            statusFilter = parsed;
+        }
+
+        var tasks = await _tasks.GetByListIdAsync(listId, cancellationToken);
+        IEnumerable<TaskEntity> query = tasks;
+        if (createdBy is not null)
+            query = query.Where(t => t.CreatedBy == createdBy);
+        if (statusFilter is not null)
+            query = query.Where(t => t.Status == statusFilter);
+
+        return query.Select(ToDto).ToList();
+    }
+
+    [McpServerTool, Description("Get a single task by id, including its current status and result.")]
+    public async Task<TaskDto> GetTask(string taskId, CancellationToken cancellationToken)
+    {
+        var task = await _tasks.GetByIdAsync(taskId, cancellationToken)
+            ?? throw new InvalidOperationException($"Task {taskId} not found.");
+        return ToDto(task);
+    }
+
+    [McpServerTool, Description("Create a new task in the given list. Set queueImmediately=true to enqueue it for agent execution.")]
+    public async Task<TaskDto> AddTask(
+        string listId,
+        string title,
+        string? description,
+        string createdBy,
+        bool queueImmediately,
+        CancellationToken cancellationToken)
+    {
+        if (string.IsNullOrWhiteSpace(listId))
+            throw new InvalidOperationException("listId is required.");
+        if (string.IsNullOrWhiteSpace(title))
+            throw new InvalidOperationException("title is required.");
+        if (string.IsNullOrWhiteSpace(createdBy))
+            throw new InvalidOperationException("createdBy is required.");
+
+        var list = await _lists.GetByIdAsync(listId, cancellationToken)
+            ?? throw new InvalidOperationException($"List {listId} not found.");
+
+        var entity = new TaskEntity
+        {
+            Id = Guid.NewGuid().ToString(),
+            ListId = listId,
+            Title = title,
+            Description = description,
+            Status = queueImmediately ? TaskStatus.Queued : TaskStatus.Manual,
+            CreatedAt = DateTime.UtcNow,
+            CommitType = list.DefaultCommitType,
+            CreatedBy = createdBy,
+        };
+        await _tasks.AddAsync(entity, cancellationToken);
+
+        if (queueImmediately)
+            _queue.WakeQueue();
+
+        await _broadcaster.TaskUpdated(entity.Id);
+        return ToDto(entity);
+    }
+
+    [McpServerTool, Description("Update a task's status. Only 'Manual' and 'Queued' are permitted — use RunTaskNow or CancelTask for execution control.")]
+    public async Task<TaskDto> UpdateTaskStatus(
+        string taskId,
+        string status,
+        CancellationToken cancellationToken)
+    {
+        if (!Enum.TryParse<TaskStatus>(status, ignoreCase: true, out var target))
+            throw new InvalidOperationException($"Unknown status '{status}'.");
+
+        var task = await _tasks.GetByIdAsync(taskId, cancellationToken)
+            ?? throw new InvalidOperationException($"Task {taskId} not found.");
+
+        switch (target)
+        {
+            case TaskStatus.Manual:
+                await _tasks.ResetToManualAsync(taskId, cancellationToken);
+                break;
+
+            case TaskStatus.Queued:
+                if (task.Status is TaskStatus.Running)
+                    throw new InvalidOperationException("Cannot enqueue a running task.");
+                task.Status = TaskStatus.Queued;
+                await _tasks.UpdateAsync(task, cancellationToken);
+                _queue.WakeQueue();
+                break;
+
+            default:
+                throw new InvalidOperationException(
+                    $"Status '{target}' is not settable externally. Use RunTaskNow or CancelTask.");
+        }
+
+        var reload = (await _tasks.GetByIdAsync(taskId, cancellationToken))!;
+        await _broadcaster.TaskUpdated(taskId);
+        return ToDto(reload);
+    }
+
+    [McpServerTool, Description("Immediately run a task in the override execution slot (bypasses the agent queue).")]
+    public async Task RunTaskNow(string taskId, CancellationToken cancellationToken)
+    {
+        try
+        {
+            await _queue.RunNow(taskId);
+        }
+        catch (InvalidOperationException)
+        {
+            throw new InvalidOperationException("Override slot busy. Try again later.");
+        }
+        catch (KeyNotFoundException)
+        {
+            throw new InvalidOperationException($"Task {taskId} not found.");
+        }
+        await _broadcaster.TaskUpdated(taskId);
+    }
+
+    [McpServerTool, Description("Cancel a running task. Returns true if the task was running and cancellation was requested.")]
+    public async Task<bool> CancelTask(string taskId, CancellationToken cancellationToken)
+    {
+        var cancelled = _queue.CancelTask(taskId);
+        if (cancelled) await _broadcaster.TaskUpdated(taskId);
+        return cancelled;
+    }
+
+    private static TaskDto ToDto(TaskEntity t) => new(
+        t.Id,
+        t.ListId,
+        t.Title,
+        t.Description,
+        t.Status.ToString(),
+        t.Result,
+        t.CreatedBy,
+        t.CreatedAt,
+        t.StartedAt,
+        t.FinishedAt);
+}
diff --git a/src/ClaudeDo.Worker/Program.cs b/src/ClaudeDo.Worker/Program.cs
index cefec7e..cfb768e 100644
--- a/src/ClaudeDo.Worker/Program.cs
+++ b/src/ClaudeDo.Worker/Program.cs
@@ -2,6 +2,7 @@ using ClaudeDo.Data;
 using ClaudeDo.Data.Git;
 using ClaudeDo.Data.Repositories;
 using ClaudeDo.Worker.Config;
+using ClaudeDo.Worker.External;
 using ClaudeDo.Worker.Hub;
 using ClaudeDo.Worker.Planning;
 using ClaudeDo.Worker.Runner;
@@ -72,6 +73,7 @@ builder.Services.AddScoped<PlanningMcpContextAccessor>();
 builder.Services.AddScoped<ClaudeDoDbContext>(sp =>
     sp.GetRequiredService<IDbContextFactory<ClaudeDoDbContext>>().CreateDbContext());
 builder.Services.AddScoped<TaskRepository>();
+builder.Services.AddScoped<ListRepository>();
 builder.Services.AddScoped<PlanningMcpService>();
 builder.Services.AddMcpServer()
     .WithHttpTransport()
@@ -108,4 +110,44 @@ app.MapMcp("/mcp");
 app.Logger.LogInformation("ClaudeDo.Worker listening on http://127.0.0.1:{Port} (db: {Db})",
     cfg.SignalRPort, cfg.DbPath);
 
-app.Run();
+// Build the external MCP endpoint as a separate WebApplication on its own port.
+// Rationale: ModelContextProtocol.AspNetCore registers one server per DI container,
+// so we need a second app to expose a different tool set under different auth.
+// Shared singletons (QueueService, HubBroadcaster, WorkerConfig, db factory) are
+// injected by instance so both apps operate on the same runtime state.
+WebApplication? externalApp = null;
+if (cfg.ExternalMcpPort > 0)
+{
+    var externalBuilder = WebApplication.CreateBuilder();
+    externalBuilder.Services.AddSingleton(cfg);
+    externalBuilder.Services.AddSingleton(app.Services.GetRequiredService<HubBroadcaster>());
+    externalBuilder.Services.AddSingleton(app.Services.GetRequiredService<QueueService>());
+    externalBuilder.Services.AddSingleton(app.Services.GetRequiredService<IDbContextFactory<ClaudeDoDbContext>>());
+    externalBuilder.Services.AddScoped<ClaudeDoDbContext>(sp =>
+        sp.GetRequiredService<IDbContextFactory<ClaudeDoDbContext>>().CreateDbContext());
+    externalBuilder.Services.AddScoped<TaskRepository>();
+    externalBuilder.Services.AddScoped<ListRepository>();
+    externalBuilder.Services.AddScoped<ExternalMcpService>();
+    externalBuilder.Services.AddMcpServer()
+        .WithHttpTransport()
+        .WithTools<ExternalMcpService>();
+    externalBuilder.WebHost.UseUrls($"http://127.0.0.1:{cfg.ExternalMcpPort}");
+
+    externalApp = externalBuilder.Build();
+    externalApp.UseMiddleware<ExternalMcpAuthMiddleware>();
+    externalApp.MapMcp("/mcp");
+
+    externalApp.Logger.LogInformation(
+        "ClaudeDo.Worker external MCP listening on http://127.0.0.1:{Port} (auth: {Auth})",
+        cfg.ExternalMcpPort,
+        string.IsNullOrEmpty(cfg.ExternalMcpApiKey) ? "loopback-only" : "X-ClaudeDo-Key");
+}
+
+if (externalApp is null)
+{
+    await app.RunAsync();
+}
+else
+{
+    await Task.WhenAll(app.RunAsync(), externalApp.RunAsync());
+}