Content
# TinyMCP
A tiny Ruby implementation of the Model Context Protocol (MCP) that makes it easy to create and serve tools locally for AI assistants.
## Installation
```bash
gem install tiny_mcp
```
## Usage
Create tools by inheriting from `TinyMCP::Tool`:
```ruby
#!/usr/bin/env ruby
require 'tiny_mcp'
class WeatherTool < TinyMCP::Tool
name 'get_weather'
desc 'Get current weather for a city'
arg :city, :string, 'City name' # required
opt :units, :string, 'Temperature units (c/f)' # optional
def call(city:, units: 'c')
# Your implementation here
"Weather in #{city}: 20°C, sunny"
end
end
class TimeTool < TinyMCP::Tool
name 'get_time'
desc 'Get current time'
opt :timezone, :string, 'Timezone name'
def call(timezone: 'UTC')
Time.now.getlocal(timezone).to_s
end
end
# Serve multiple tools
TinyMCP.serve(WeatherTool, TimeTool)
```
You can put this in a `bin/mcp` file for example, and make it executable:
```bash
chmod +x bin/mcp
```
Then add it to Claude Code:
```bash
claude mcp add my-mcp bin/mcp
```
The server reads JSON-RPC requests from stdin and writes responses to stdout.
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and the created tag, and push the `.gem` file to [rubygems.org](https://rubygems.org).
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/maxim/tiny_mcp. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [code of conduct](https://github.com/maxim/tiny_mcp/blob/main/CODE_OF_CONDUCT.md).
## License
The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).
## Code of Conduct
Everyone interacting in the TinyMCP project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://github.com/maxim/tiny_mcp/blob/main/CODE_OF_CONDUCT.md).