strowk/foxy-contexts

Build MCP Servers Declaratively in Golang
Features 🦊
Tool Example 🦊
Docs 🦊
Sources
Foxy contexts is a Golang library for building context servers supporting Model Context Protocol.
This library only supports server side of the protocol. Using it you can build context servers using declarative approach, by defining tools, resources and prompts and then registering them with your app.Builder, which is using uber's fx App under the hood and you can inject into its container as well.
With this approach you can easily colocate call/read/get logic and definitions of your tools/resources/prompts in a way that every tool/resource/prompt is placed in a separate place, while Dependency Injection allows you to reuse shared parts like clients, database connections, etc.
Features
Here is list of features that are implemented and planned:
- [x] Base (lifecycle/ping)
- [ ] Progress (planned)
- [x] Transports
- [x] Stdio Transport
- [x] SSE Transport
- [x] Streamable HTTP Transport (beta)
- [x] Tools
- [x] Package toolinput helps define tools input schema and validate arriving input
- [ ] Resources
- [x] Resources - static
- [x] Resources - dynamic via Resource Providers
- [ ] Resources - dynamic via Resource Templates (planned)
- [ ] Resource Templates completion (planned)
- [ ] Resource subscriptions
- [x] Prompts
- [x] Prompts Completion
- [x] Functional Testing package foxytest
- [x] Simple building of your MCP server with the power of Dependency Injection
- [ ] Logging via MCP (planned)
- [ ] Sampling (planned)
- [ ] Roots (planned)
- [ ] Pagination (planned)
- [ ] Notifications list_changed (planned)
- [x] Testing - functional tests with foxytest package
Check docs and examples to know more.
Tool Example
For example try following
, then once inspector is started in browser open http://localhost:6274 and try to use list-current-dir-files.
Here's the code of that example from examples/list_current_dir_files_tool/main.go (in real world application you would probably want to split it into multiple files):