MCP Dev Server Manager

A daemon process that runs continuously and accepts multiple concurrent MCP client connections, sharing dev server session state across all clients.

Features

• Multi-client daemon with shared global state
• STDIO and SSE transport support
• Automatic port allocation starting at 3010 with reuse
• Log capture with 512KB ring buffers per server
• Auto-cleanup of idle sessions after 60 seconds
• Process management with stdout/stderr capture

Building

cargo build --release

The binary will be at target/release/mcp-dev-manager.

Running

Start the Daemon

# Foreground
./target/release/mcp-dev-manager

# Background
./target/release/mcp-dev-manager &

The daemon will listen on http://127.0.0.1:3009.

Client Configuration

STDIO Transport (Recommended)

For Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "dev-manager": {
      "command": "mcp-dev-manager-stdio"
    }
  }
}

The STDIO proxy connects to the daemon at http://127.0.0.1:3009/sse by default. To use a different URL, set the MCP_DAEMON_URL environment variable:

{
  "mcpServers": {
    "dev-manager": {
      "command": "mcp-dev-manager-stdio",
      "env": {
        "MCP_DAEMON_URL": "http://127.0.0.1:3009/sse"
      }
    }
  }
}

SSE Transport (Legacy)

For Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "dev-manager": {
      "url": "http://127.0.0.1:3009/sse"
    }
  }
}

Multiple clients can use the same configuration and will share session state.

MCP Tools

start

Start a development server. Auto-generates a unique 4-character session key.

Parameters:

• command (string): Shell command to execute (e.g., "npm run dev", "python -m http.server 8080")
• cwd (optional string): Working directory for the command. When using STDIO transport, defaults to client's working directory.

Returns:

{
  "status": "started",
  "port": 3010,
  "session_key": "A3X9"
}

stop

Stop a running development server session.

Parameters:

• session_key (string): Session identifier

Returns:

{
  "status": "stopped",
  "session_key": "A3X9"
}

status

Get status of one or all development server sessions.

Parameters:

• session_key (optional string): Specific session to query, or omit for all sessions

Returns:

{
  "sessions": [
    {
      "session_key": "B7K2",
      "port": 3010,
      "running": true
    }
  ]
}

tail

Get stdout/stderr logs for a development server session.

Parameters:

• session_key (string): Session identifier (e.g., "A3X9")

Returns:

{
  "session_key": "A3X9",
  "stdout": "Server started on port 3010...",
  "stderr": ""
}

Architecture

Modules

• port_allocator.rs - Sequential port allocation from 3010 with free list
• log_buffer.rs - Bounded 512KB ring buffer with Clone support
• server_entry.rs - Process wrapper with async log capture
• manager.rs - Shared state manager with auto-cleanup sweeper
• service.rs - MCP service with tool definitions
• main.rs - HTTP/SSE daemon server

State Management

• Single Arc<Manager> shared across all client connections
• Each connection gets a fresh DevManagerService instance
• Mutex-protected HashMap for session storage
• Background sweeper runs every 5 seconds to clean up idle sessions (>60s)

Session Keys

• Auto-generated 4-character uppercase alphanumeric codes (e.g., "A3X9", "K7M2")
• Guaranteed unique across active sessions
• 1,679,616 possible combinations (36^4)

Port Allocation

• Starts at 3010 and increments sequentially
• Maintains free list for reused ports
• Probes availability with TcpListener before assignment

Log Capture

• Each server spawns two async tasks for stdout/stderr
• Logs stored in bounded VecDeque with byte tracking
• Oldest entries evicted when 512KB limit reached
• Non-blocking reads with line buffering

Testing Multi-Client Behavior

1. Start daemon: ./target/release/mcp-dev-manager
2. Connect Client A and start a server session
3. Connect Client B and query status - should see Client A's session
4. Client B can stop Client A's session
5. All clients share the same session state

License

MIT