Magg

Official

by sitbon · Python

Aggregates and proxies other MCP servers, letting LLMs discover, add, and manage tools at runtime.

io.github.sitbon/magg — Model Context Protocol (MCP) Aggregator Server

The io.github.sitbon/magg MCP server aggregates and proxies other MCP servers. It enables LLMs to discover, add, and manage available tools at runtime by routing requests through the aggregated server layer.

🛠️ Key Features

Aggregates other MCP servers
Proxies requests to other MCP servers
Supports LLM-driven discovery of available tools
Allows adding and managing tools at runtime

🚀 Use Cases

Dynamic tool discovery across multiple MCP servers
Centralized tool access via an aggregator/proxy layer
Runtime selection and management of tools for LLM sessions

⚡ Developer Benefits

One integration point for multiple MCP tool sources
Runtime tool discovery and management without static configuration

⚠️ Limitations

The server description only specifies aggregation/proxying and runtime tool management; no additional capabilities, requirements, or constraints are provided.

Topics

aggregatoraidockerdocker-composefastmcpjson-rpcllmmcpmcp-sdkmcp-servermcp-serversmodelcontextprotocolproxypydanticpydantic-v2python

readme.md20 KBView on GitHub

🧲 Magg - The MCP Aggregator

A Model Context Protocol server that manages, aggregates, and proxies other MCP servers, enabling LLMs to dynamically extend their own capabilities.

What is Magg?

Magg is a meta-MCP server that acts as a central hub for managing multiple MCP servers. It provides tools that allow LLMs to:

Search for new MCP servers and discover setup instructions
Add and configure MCP servers dynamically
Enable/disable servers on demand
Aggregate tools from multiple servers under unified prefixes
Persist configurations across sessions

Think of Magg as a "package manager for LLM tools" - it lets AI assistants install and manage their own capabilities at runtime.

Features

Self-Service Tool Management: LLMs can search for and add new MCP servers without human intervention.
Dynamic Configuration Reloading: Automatically detects and applies config changes without restarting.
Automatic Tool Proxying: Tools from added servers are automatically exposed with configurable prefixes.
ProxyMCP Tool: A built-in tool that proxies the MCP protocol to itself, for clients that don't support notifications or dynamic tool updates (which is most of them currently).
Smart Configuration: Uses MCP sampling to intelligently configure servers from just a URL.
Persistent Configuration: Maintains server configurations in .magg/config.json.
Multiple Transport Support: Works with stdio, HTTP, and in-memory transports.
Bearer Token Authentication: Optional RSA-based JWT authentication for secure HTTP access.
Docker Support: Pre-built images for production, staging, and development workflows.
Health Monitoring: Built-in magg_status and magg_check tools for server health checks.
Real-time Messaging: Full support for MCP notifications and messages - receive tool/resource updates and progress notifications from backend servers.
Python 3.12+ Support: Fully compatible with Python 3.12 and 3.13.
Kit Management: Bundle related MCP servers into kits for easy loading/unloading as a group.
MBro CLI: Included MCP Browser for interactive exploration and management of MCP servers, with script support for automation.

Installation

Prerequisites

Python 3.12 or higher (3.13+ recommended)
uv (recommended) - Install from astral.sh/uv

Quick Install (Recommended)

The easiest way to install Magg is as a tool using uv:

bash

# Install Magg as a tool
uv tool install magg

# Run with stdio transport (for Claude Desktop, Cline, etc.)
magg serve

# Run with HTTP transport (for system-wide access)
magg serve --http

Alternative: Run Directly from GitHub

You can also run Magg directly from GitHub without installing:

bash

# Run with stdio transport
uvx --from git+https://github.com/sitbon/magg.git magg

# Run with HTTP transport
uvx --from git+https://github.com/sitbon/magg.git magg serve --http

Local Development

For development, clone the repository and install in editable mode:

bash

# Clone the repository
git clone https://github.com/sitbon/magg.git
cd magg

# Install in development mode with dev dependencies
uv sync --dev

# Or with poetry
poetry install --with dev

# Run the CLI
magg --help

Docker

Magg is available as pre-built Docker images from GitHub Container Registry:

bash

# Run production image (WARNING log level)
docker run -p 8000:8000 ghcr.io/sitbon/magg:latest

# Run with authentication (mount or set private key)
docker run -p 8000:8000 \
  -v ~/.ssh/magg:/home/magg/.ssh/magg:ro \
  ghcr.io/sitbon/magg:latest

# Or with environment variable
docker run -p 8000:8000 \
  -e MAGG_PRIVATE_KEY="$(cat ~/.ssh/magg/magg.key)" \
  ghcr.io/sitbon/magg:latest

# Run beta image (INFO log level)
docker run -p 8000:8000 ghcr.io/sitbon/magg:beta

# Run with custom config directory
docker run -p 8000:8000 \
  -v /path/to/config:/home/magg/.magg \
  ghcr.io/sitbon/magg:latest

Docker Image Strategy

Magg uses a multi-stage Docker build with three target stages:

pro (Production): Minimal image with WARNING log level, suitable for production deployments
pre (Pre-production): Same as production but with INFO log level for staging/testing (available but not published)
dev (Development): Includes development dependencies and DEBUG logging for troubleshooting

Images are automatically published to GitHub Container Registry with the following tags:

Version tags (from main branch): 1.2.3, 1.2, dev, 1.2-dev, 1.2-dev-py3.12, etc.
Branch tags (from beta branch): beta, beta-dev
Python-specific dev tags: beta-dev-py3.12, beta-dev-py3.13, etc.

Pull requests build and test images but do not publish them unless a maintainer adds the push-image label, which publishes ephemeral pr-NN / pr-NN-dev tags (same-repo PRs only). Ephemeral pr-* tags and untagged manifests are cleaned up weekly; version tags are kept forever, so pinned deployments are never affected.

Docker Compose

For easier management, use Docker Compose:

bash

# Clone the repository
git clone https://github.com/sitbon/magg.git
cd magg

# Run production version
docker compose up magg

# Run staging version (on port 8001)
docker compose up magg-beta

# Run development version (on port 8008)
# This uses ./.magg/config.json for configuration
docker compose up magg-dev

# Build and run with custom registry
REGISTRY=my.registry.com docker compose build
REGISTRY=my.registry.com docker compose push

See compose.yaml and .env.example for configuration options.

Usage

Running Magg

Magg can run in three modes:

Stdio Mode (default) - For integration with Claude Desktop, Cline, Cursor, etc.:
bash
```
magg serve
```
HTTP Mode - For system-wide access or web integrations:
bash
```
magg serve --http --port 8000
```

Hybrid Mode - Both stdio and HTTP simultaneously:

bash

magg serve --hybrid
magg serve --hybrid --port 8080  # Custom port

This is particularly useful when you want to use Magg through an MCP client while also allowing HTTP access. For example:

With Claude Code:

bash

# Configure Claude Code to use Magg in hybrid mode
claude mcp add magg -- magg serve --hybrid --port 42000

With mbro:

bash

# mbro hosts Magg and connects via stdio
mbro connect magg "magg serve --hybrid --port 8080"

# Other mbro instances can connect via HTTP
mbro connect magg http://localhost:8080

Available Tools

Once Magg is running, it exposes the following tools to LLMs:

magg_list_servers - List all configured MCP servers
magg_add_server - Add a new MCP server
magg_remove_server - Remove a server
magg_enable_server / magg_disable_server - Toggle server availability
magg_search_servers - Search for MCP servers online
magg_list_tools - List all available tools from all servers
magg_smart_configure - Intelligently configure a server from a URL
magg_analyze_servers - Analyze configured servers and suggest improvements
magg_status - Get server and tool statistics
magg_check - Health check servers with repair actions (report/remount/unmount/disable)
magg_reload_config - Reload configuration from disk and apply changes
magg_load_kit - Load a kit and its servers into the configuration
magg_unload_kit - Unload a kit and optionally its servers from the configuration
magg_list_kits - List all available kits with their status
magg_kit_info - Get detailed information about a specific kit

Quick Inspection with MBro

Magg includes the mbro (MCP Browser) CLI tool for interactive exploration. A unique feature is the ability to connect to Magg in stdio mode for quick inspection:

bash

# Connect mbro to a Magg instance via stdio (no HTTP server needed)
mbro connect local-magg magg serve

# Now inspect your Magg setup from the MCP client perspective
mbro:local-magg> call magg_status
mbro:local-magg> call magg_list_servers

MBro also supports:

Scripts: Create .mbro files with commands for automation
Shell-style arguments: Use key=value syntax instead of JSON
Tab completion: Rich parameter hints after connecting

See the MBro Documentation for details.

Authentication

Magg supports optional bearer token authentication to secure access:

Quick Start

Initialize authentication (creates RSA keypair):
bash
```
magg auth init
```

Generate a JWT token for clients:

bash

# Generate token (displays on screen)
magg auth token

# Export as environment variable
export MAGG_JWT=$(magg auth token -q)

Connect with authentication:

Using MaggClient (auto-loads from MAGG_JWT):

python

from magg.client import MaggClient

async def main():
    async with MaggClient("http://localhost:8000/mcp") as client:
        tools = await client.list_tools()

Using FastMCP with explicit token:

python

from fastmcp import Client
from fastmcp.client import BearerAuth

jwt_token = "your-jwt-token-here"
async with Client("http://localhost:8000/mcp", auth=BearerAuth(jwt_token)) as client:
    tools = await client.list_tools()

Key Management

Keys are stored in ~/.ssh/magg/ by default
Private key can be set via MAGG_PRIVATE_KEY environment variable
To disable auth, remove keys or set non-existent key_path in .magg/auth.json

Authentication Commands

magg auth init - Initialize authentication (generates RSA keypair)
magg auth status - Check authentication configuration
magg auth token - Generate JWT token
magg auth public-key - Display public key (for verification)
magg auth private-key - Display private key (for backup)

See examples/authentication.py for more usage patterns.

Configuration

Magg stores its configuration in .magg/config.json in your current working directory. This allows for project-specific tool configurations.

Dynamic Configuration Reloading

Magg supports automatic configuration reloading without requiring a restart:

Automatic file watching: Detects changes to config.json and reloads automatically (uses watchdog when available)
SIGHUP signal: Send kill -HUP <pid> to trigger immediate reload (Unix-like systems)
MCP tool: Use magg_reload_config tool from any MCP client
Smart transitions: Only affected servers are restarted during reload

Configuration reload is enabled by default. You can control it with:

MAGG_AUTO_RELOAD=false - Disable automatic reloading
MAGG_RELOAD_POLL_INTERVAL=5.0 - Set polling interval in seconds (when watchdog unavailable)

See Configuration Reload Documentation for detailed information.

Environment Variables

Magg supports several environment variables for configuration:

MAGG_CONFIG_PATH - Path to config file (default: .magg/config.json)
MAGG_LOG_LEVEL - Logging level: DEBUG, INFO, WARNING, ERROR, CRITICAL (default: INFO)
MAGG_STDERR_SHOW=1 - Show stderr output from subprocess MCP servers (default: suppressed)
MAGG_AUTO_RELOAD - Enable/disable config auto-reload (default: true)
MAGG_RELOAD_POLL_INTERVAL - Config polling interval in seconds (default: 1.0)
MAGG_READ_ONLY=true - Run in read-only mode
MAGG_SELF_PREFIX - Prefix for Magg tools (default: "magg"). Tools will be named as {prefix}{sep}{tool} (e.g., magg_list_servers)
MAGG_PREFIX_SEP - Separator between prefix and tool name (default: "_")

Example configuration:

json

{
  "servers": {
    "calculator": {
      "name": "calculator",
      "source": "https://github.com/executeautomation/calculator-mcp",
      "command": "npx @executeautomation/calculator-mcp",
      "prefix": "calc",
      "enabled": true
    }
  }
}

Adding Servers

Servers can be added in several ways:

Using the LLM (recommended):

code

"Add the Playwright MCP server"
"Search for and add a calculator tool"

Manual configuration via magg_add_server:

code

name: playwright
url: https://github.com/microsoft/playwright-mcp
command: npx @playwright/mcp@latest
prefix: pw

The magg server CLI (see below)
Direct config editing: Edit .magg/config.json directly

Managing Servers from the CLI

Server and kit configuration can be managed entirely from the command line — no MCP client or running server required. The CLI edits .magg/config.json directly, and a running Magg instance picks up the changes automatically via config reload. (Tools that require a live server, like magg_search_servers, magg_check, and magg_smart_configure, remain available through any MCP client such as mbro.)

bash

# List servers (human-readable, or JSON on stdout for scripting)
magg server list
magg server list --json

# Add a server
magg server add playwright https://github.com/microsoft/playwright-mcp \
    --command "npx @playwright/mcp@latest" --prefix pw

# Add a server without enabling it, with transport options
magg server add web https://example.com/web --uri http://localhost:9000/mcp \
    --transport '{"keep_alive": false}' --disable

# Update an existing server (pass '' to clear an optional field)
magg server update playwright --prefix play --notes "Browser automation"
magg server update playwright --command "npx @playwright/mcp@next"
magg server update playwright --notes ""

# Enable / disable / inspect / remove
magg server enable playwright
magg server disable playwright
magg server info playwright --json
magg server remove playwright

Real-time Notifications with MaggClient

The MaggClient now supports real-time notifications from backend MCP servers:

python

from magg import MaggClient, MaggMessageHandler

# Using callbacks
handler = MaggMessageHandler(
    on_tool_list_changed=lambda n: print("Tools changed!"),
    on_progress=lambda n: print(f"Progress: {n.params.progress}")
)

async with MaggClient("http://localhost:8000/mcp", message_handler=handler) as client:
    # Client will receive notifications while connected
    tools = await client.list_tools()

See Messaging Documentation for advanced usage including custom message handlers.

Kit Management

Magg supports organizing related MCP servers into "kits" - bundles that can be loaded and unloaded as a group:

bash

# List available kits
magg kit list

# Load a kit (adds all its servers)
magg kit load web-tools

# Unload a kit (removes servers only in that kit)
magg kit unload web-tools

# Get information about a kit
magg kit info web-tools

# Export the current configuration (or a loaded kit) as a kit file
magg kit export --name my-kit --output my-kit.json

When unloading a kit, servers that belong only to that kit are removed, while servers shared with other kits are kept.

You can also manage kits programmatically through Magg's tools when connected via an MCP client:

magg_list_kits - List all available kits
magg_load_kit - Load a kit and its servers
magg_unload_kit - Unload a kit
magg_kit_info - Get detailed kit information

Kits are JSON files stored in ~/.magg/kit.d/ or .magg/kit.d/ that define a collection of related servers. See Kit Documentation for details on creating and managing kits.

MBro Scripts

Automate common workflows with MBro scripts:

bash

# Create a setup script
cat > setup.mbro <<EOF
# Connect to Magg and check status
connect magg magg serve
call magg_status
call magg_list_servers

# Add a new server if needed
call magg_add_server name=calculator source="npx -y @modelcontextprotocol/server-calculator"
EOF

# Run the script
mbro -x setup.mbro

MCP 2026-07-28 (Stateless Spec)

The MCP 2026-07-28 spec moves the protocol to a stateless request/response core. Magg's take: something still has to own long-lived stdio subprocesses, backend connections, and tool-list caching — and that's exactly the layer an aggregator provides. See Magg and the Stateless MCP Spec for the impact analysis and migration plan, including how Magg bridges pre-2026 (stateful) backends to stateless-era clients and how hierarchical Magg deployments fit in.

Documentation

For more documentation, see docs/.

Appearances

Magg appears in multiple locations. Please feel free to submit a PR to add more appearances below in alphabetical order.

Listing, Index, and other MCP Sites

DeepWiki - AI-generated documentation
Glama.ai - MCP server listing and hosting

Magg ships a server.json manifest for the official MCP Registry (as io.github.sitbon/magg), and magg_search_servers queries the registry as a first-class discovery source alongside Glama, GitHub, and npm. See MCP Registry Documentation for publishing instructions.

mcp-name: io.github.sitbon/magg

Awesome GitHub MCP Lists

Install

Add to VS Code Add to Cursor

claude_desktop_config.json

json

{
  "mcpServers": {
    "magg": {
      "command": "uvx",
      "args": [
        "magg",
        "serve"
      ]
    }
  }
}