# Bundler Mcp

> A Model Context Protocol (MCP) server enabling AI agents to query information about gems in a Ruby project's Gemfile, including source code and metadata.

- **Type:** MCP server
- **Install:** `agentstack add mcp-subelsky-bundler-mcp`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [subelsky](https://agentstack.voostack.com/s/subelsky)
- **Installs:** 0
- **Category:** [Integrations](https://agentstack.voostack.com/c/integrations)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [subelsky](https://github.com/subelsky)
- **Source:** https://github.com/subelsky/bundler_mcp
- **Website:** https://rubygems.org/gems/bundler_mcp

## Install

```sh
agentstack add mcp-subelsky-bundler-mcp
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# BundlerMCP

A Model Context Protocol (MCP) server enabling AI agents to query information about dependencies in a Ruby project's `Gemfile`. Built with [fast-mcp](https://github.com/yjacquin/fast-mcp).

[](https://github.com/subelsky/bundler_mcp/actions/workflows/main.yml)
[](https://badge.fury.io/rb/bundler_mcp)

## Installation

Install the gem and add to the application's Gemfile by executing:

```bash
bundle add bundler_mcp --group=development
```

## Usage

1. Generate the binstub:

```bash
bundle binstubs bundler_mcp
```

2. Configure your client to execute the binstub. Here are examples that work for Claude and Cursor:

### Basic Example (mcp.json)

```json
{
  "mcpServers": {
    "bundler-mcp": {
      "command": "/Users/mike/my_project/bin/bundler_mcp"
    }
  }
}
```

### Example with logging and explicit Gemfile

```json
{
  "mcpServers": {
    "bundler-mcp": {
      "command": "/Users/mike/my_project/bin/bundler_mcp",

      "env": {
        "BUNDLER_MCP_LOG_FILE": "/Users/mike/my_project/log/mcp.log",
        "BUNDLE_GEMFILE": "/Users/mike/my_project/subdir/Gemfile"
      }
    }
  }
}
```

### Documentation

[Available on RubyDoc](https://www.rubydoc.info/gems/bundler_mcp/)

### Available Tools

The server provides two tools for AI agents:

#### list_project_gems

Lists all bundled Ruby gems with their:

- Versions
- Descriptions
- Installation paths
- Top-level documentation locations (e.g. `README` and `CHANGELOG`)

#### get_gem_details

Retrieves detailed information about a specific gem, including:

- Version
- Description
- Installation path
- Top-level documentation locations
- Source code file locations

## Environment Variables

- `BUNDLE_GEMFILE`: Used by Bundler to locate your Gemfile. If you use the binstub method described in the [Usage](#usage) section, this is usually not needed.
- `BUNDLER_MCP_LOG_FILE`: Path to log file. Useful for troubleshooting (defaults to no logging)

## Development

After checking out the repo, run `bin/setup` to install dependencies and `bundle exec rspec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.

### Testing with the MCP Inspector

You can test the server directly using the [MCP inspector](https://modelcontextprotocol.io/docs/tools/inspector):

```bash
# Basic usage
npx @modelcontextprotocol/inspector ./bin/bundler_mcp

# With logging enabled
BUNDLER_MCP_LOG_FILE=/tmp/log/mcp.log npx @modelcontextprotocol/inspector ./bin/bundler_mcp

# With custom Gemfile
BUNDLE_GEMFILE=./other/Gemfile npx @modelcontextprotocol/inspector ./bin/bundler_mcp
```

### Release Process

To install this gem onto your local machine, run `bundle exec rake install`. To release a new version:

1. Update the version number in `version.rb`
2. Run `bundle exec rake release`

This will:

- Create a git tag for the version
- Push git commits and the created tag
- Push the `.gem` file to [rubygems.org](https://rubygems.org)

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/subelsky/bundler_mcp.

## License

Open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).

## Author

[Mike Subelsky](https://subelsky.com)

## Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [subelsky](https://github.com/subelsky)
- **Source:** [subelsky/bundler_mcp](https://github.com/subelsky/bundler_mcp)
- **License:** MIT
- **Homepage:** https://rubygems.org/gems/bundler_mcp

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/mcp-subelsky-bundler-mcp
- Seller: https://agentstack.voostack.com/s/subelsky
- Browse the marketplace: https://agentstack.voostack.com/browse

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