https://github.com/maxim/tiny_mcp
Make local MCP tools in Ruby and easily serve them
https://github.com/maxim/tiny_mcp
Last synced: 10 months ago
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Make local MCP tools in Ruby and easily serve them
- Host: GitHub
- URL: https://github.com/maxim/tiny_mcp
- Owner: maxim
- License: mit
- Created: 2025-05-26T04:08:37.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2025-06-10T02:34:11.000Z (about 1 year ago)
- Last Synced: 2025-08-01T11:52:58.303Z (11 months ago)
- Language: Ruby
- Size: 27.3 KB
- Stars: 64
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.txt
- Code of conduct: CODE_OF_CONDUCT.md
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README
# 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)
end
end
# Serve multiple tools
TinyMCP.serve(WeatherTool, TimeTool, server_name: 'my_tool')
```
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.
See [examples/](examples/) for more.
## Multiple results and different formats
By default TinyMCP assumes you're returning `text` from your call function. If you want to return image, audio, or a bunch of different results, wrap your return value in an array, and TinyMCP will treat your return value as the whole `content` body.
Don't forget that binary data such as images and audio needs to be Base64-encoded.
```ruby
require 'base64'
class MultiModalTool < TinyMCP::Tool
name 'get_different_formats'
desc 'Get results in different formats'
def call
[
{
type: 'text',
text: 'This is a text response'
},
{
type: 'image',
mimeType: 'image/png',
data: Base64.strict_encode64(File.binread('image.png'))
},
{
type: 'audio',
mimeType: 'audio/mpeg',
data: Base64.strict_encode64(File.binread('audio.mp3'))
}
]
end
end
```
## 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).