AgentBrew 🍺

The Universal Hub for AI Agents.

AgentBrew is a centralized Model Context Protocol (MCP) multiplexer. Install your tools and skills once — every AI agent you use picks them up automatically.

💡 The Core Idea

AI developers today face a fragmentation problem: every agent (Claude Code, Gemini CLI, Cursor, etc.) has its own way of managing MCP servers, tools, and skills. Setting up your favorite tools in one agent doesn't mean you have them in another.

AgentBrew solves this by acting as a Universal "USB Hub" for MCP. You install your tools once in AgentBrew, and all your agents can instantly access that same consistent set of capabilities. If you switch agents, your entire "brew" of tools and skills comes with you.

How Skills Work

AgentBrew exposes skills (packages containing a SKILL.md file) as MCP tools. This is the primary delivery mechanism — it works in every agent that supports MCP, with no extra setup beyond registering agentbrew as a server.

AI Agent (Claude, Gemini, Cursor, Windsurf, Kiro…)
    │  MCP (stdio)
    ▼
AgentBrew Router
    │
    ├── Skills → MCP tools (universal, works in all agents automatically)
    │       Agent calls the tool → receives SKILL.md instructions → follows them
    │
    ├── MCP Servers → proxied to child processes (lazy-spawned)
    │
    └── Instructions → MCP resources (CLAUDE.md, GEMINI.md, KIRO.md, .cursorrules…)

Running agentbrew sync adds a second layer on top:

| Agent | After MCP registration | After agentbrew sync | |---|---|---| | Claude Code | Skills as MCP tools (AI-initiated) | + /skill-name slash commands (user-initiated) | | Gemini CLI | Skills as MCP tools | + Extension slash commands | | Cursor | Skills as MCP tools (auto-registered) | No change — Cursor uses MCP natively | | Windsurf | Skills as MCP tools | + Native skill slash commands | | Antigravity | Skills as MCP tools | + Native skill slash commands | | Codex CLI | Skills as MCP tools (auto-registered) | No change — Codex uses MCP natively | | Amazon Kiro | Skills as MCP tools (auto-registered) | + Steering file with shared instructions |

Claude Code note: After sync, Claude Code has both interfaces simultaneously. They are complementary, not duplicates:

• /skill-name — you or the AI explicitly invokes the skill; SKILL.md is injected as conversation context.
• pkg__skill-name MCP tool — the AI calls this autonomously mid-task without user input. Both read the same SKILL.md file on disk (the sync creates symlinks, not copies).

🚀 Key Features

• Universal Skill Delivery: Skills are immediately available as MCP tools in every connected agent — no sync required.
• Lazy Loading: Child MCP servers only start when a tool is actually called.
• Auto-Discovery: Automatically detects MCP servers in Node.js, Python, and Markdown projects. Detects per-agent instruction files (CLAUDE.md, GEMINI.md, KIRO.md, AGENTS.md, .cursorrules, etc.) shipped inside packages.
• Universal Migration: Import your existing configurations from Gemini, Claude Code, Cursor, Codex, Windsurf, and Kiro.
• Shared Instructions: Write agent instructions once in ~/.agentbrew/INSTRUCTIONS.md and push them to every agent's global config with agentbrew sync.
• Native Slash Commands (optional): agentbrew sync also registers skills as native slash commands in Claude Code, Gemini CLI, Windsurf, and Antigravity.

🛠 Installation

📦 Via npm Registry (Recommended)

npm install -g @patchen0518/agentbrew

🔨 Manual Development Setup

# Clone and enter the repo
git clone https://github.com/patchen0518/AgentBrew.git
cd AgentBrew

# Install dependencies and build
npm install
npm run build

# Link the local build globally
npm link

📖 Usage

First Steps

After installing AgentBrew, the recommended setup is:

# 1. Install a package
agentbrew install <github-url>

# 2. Connect your agent (see "Connecting Agents" below)
#    Skills and tools are now live in your agent as MCP capabilities.

# 3. Run sync to push shared instructions and enable native slash commands
agentbrew sync

Step 3 is optional but recommended — it unlocks slash command discoverability in Claude Code and Gemini CLI and lets you maintain shared instructions across all your agents.

Installing Tools & Skills

# Install a tool or skill package from a Git URL
agentbrew install <github-url>

# Migrate from Gemini, Claude, Cursor, Codex, Windsurf, or Kiro
agentbrew migrate

Installation failed? If agentbrew install fails (missing dependencies, build errors, etc.), ask your AI agent directly:

"Install <github-url> to agentbrew for me." The agent can run the install command, read any error output, and resolve issues autonomously.

API keys: If a package requires credentials to start its MCP server, discovery may fail silently at install time. AgentBrew will warn you which servers need attention. Set the required environment variables and run agentbrew refresh to complete setup.

🔑 Dedicated Credentials

For servers requiring custom credentials, configure them in the package's agentbrew.toml manifest file:

# ~/.agentbrew/packages/linked-custom-server/agentbrew.toml
[[servers]]
name = "custom-server"
command = "node"
args = ["index.js"]
[servers.env]
API_TOKEN = "your-secret-token-here"

📝 Shared Instructions & Skill Sync

agentbrew sync does two things:

1. Injects shared instructions from ~/.agentbrew/INSTRUCTIONS.md into every agent's global config file.
2. Registers skills as native slash commands in Claude Code, Gemini CLI, Windsurf, and Antigravity (in addition to the MCP tools that are already active).

Workflow:

# 1. First run creates an example INSTRUCTIONS.md — nothing is written yet
agentbrew sync

# 2. Edit with your shared rules (e.g. "always use Context7 before calling external APIs")
open ~/.agentbrew/INSTRUCTIONS.md

# 3. Push instructions and register slash commands in all detected agents
agentbrew sync

After syncing:

• A clearly-marked AgentBrew Shared section is injected into each agent's global config (~/.claude/CLAUDE.md, ~/.gemini/GEMINI.md, ~/.codex/AGENTS.md, etc.).
• Skills are registered as slash commands in Claude Code (~/.claude/skills/), Gemini CLI, Windsurf, and Antigravity via symlinks — no content is duplicated on disk.
• For Cursor, agentbrew is automatically registered as an MCP server in ~/.cursor/mcp.json — no manual steps required.
• For Codex CLI, agentbrew is automatically registered as an MCP server in ~/.codex/config.toml — no manual steps required.
• For Amazon Kiro, agentbrew is automatically registered as an MCP server in ~/.kiro/settings/mcp.json, and shared instructions are written to ~/.kiro/steering/agentbrew-shared.md (always-active steering file) — no manual steps required.

# Remove all injected instructions and skill registrations
agentbrew unsync

[!NOTE] agentbrew sync only writes to agents that are detected as installed on your machine (their config directory must exist). Agents you haven't installed are silently skipped.

Advanced: Claude Code users who prefer skills to be accessible only via slash commands (and not as AI-callable MCP tools) can set "skillsAsMcpTools": false in ~/.agentbrew/state.json. The default is true — both interfaces are active.

Managing the Hub

# List all tools, prompts, and resources
agentbrew list

# List with tool/prompt/resource counts from the capability cache
agentbrew list --verbose

# Enable/Disable a package or a specific capability
agentbrew enable <package-name>
agentbrew enable <package-name> <capability>
agentbrew disable <package-name>
agentbrew disable <package-name> <capability>

# Uninstall a package or a specific capability (cache is auto-refreshed)
agentbrew uninstall <package-name>
agentbrew uninstall <package-name> <capability>

# Update a specific package or all packages
agentbrew update <package-name>
agentbrew update --all

# Refresh capability cache (required after manual file changes, or after setting API keys)
agentbrew refresh

# Refresh and re-run dependency installation (use after a manual git clone)
agentbrew refresh --install

🤖 Connecting Agents

Point your AI agent to launch agentbrew as its MCP server. Once connected, all installed tools and skills are immediately available.

• Gemini CLI: gemini mcp add agentbrew agentbrew
• Claude Code: /plugin add agentbrew agentbrew
• Cursor: Run agentbrew sync — agentbrew is automatically registered in ~/.cursor/mcp.json. No manual steps required.
• Codex CLI: Run agentbrew sync — agentbrew is automatically registered in ~/.codex/config.toml if Codex CLI is installed. Or manually: codex mcp add agentbrew agentbrew
• Amazon Kiro: Run agentbrew sync — agentbrew is automatically registered in ~/.kiro/settings/mcp.json if Kiro is installed. No manual steps required.
• Windsurf / Antigravity: Add agentbrew as an MCP server, then run agentbrew sync to also register slash commands.

After connecting, run agentbrew sync to enable native slash commands and shared instructions.

Manual JSON Configuration

For agents that use a configuration file (like Claude Desktop or other MCP clients):

File Paths:

• Claude Desktop (macOS): ~/Library/Application Support/Claude/claude_desktop_config.json
• Claude Desktop (Windows): %APPDATA%\Claude\claude_desktop_config.json

Configuration:

{
  "mcpServers": {
    "agentbrew": {
      "command": "agentbrew"
    }
  }
}

[!TIP] Path Resolution Fallback: If your agent cannot resolve the global agentbrew command (e.g., throwing a "command not found" error during startup), run via node directly:

{
  "mcpServers": {
    "agentbrew": {
      "command": "node",
      "args": ["/absolute/path/to/AgentBrew/dist/cli.js"]
    }
  }
}

🏗 Architecture

AgentBrew uses an mcp-manifest.json cache in each package directory for instant startup. The Router acts as a dynamic proxy, spawning child MCP processes on-demand and routing requests using a scoped naming convention: {packageName}_{serverName}__{toolName}. The __ (double-underscore) is the reserved routing delimiter — package and server names must never contain it.

📄 License

MIT