Implementations

Six official implementations, all MIT licensed and zero runtime dependencies. The current spec v3.2 contract is defined by 174 conformance fixtures. All six implementations pass 174/174 with 43B+ combined round-trips verified.

Official Implementations

Language	Package	Install	Registry	Status
Go	gcf-go	go get github.com/blackwell-systems/gcf-go@v1.3.1	pkg.go.dev	v1.3.1 · 174/174 · 1B+ RT
TypeScript	@blackwell-systems/gcf	npm install @blackwell-systems/gcf@2.2.1	npm	v2.2.1 · 174/174 · 20M RT
Python	gcf-python	pip install gcf-python==2.2.1	PyPI	v2.2.1 · 174/174 · 10M RT
Rust	gcf	cargo add gcf@2.2.1	crates.io	v2.2.1 · 174/174 · 43B+ RT
Swift	GCF	.package(url: "https://github.com/blackwell-systems/gcf-swift", from: "2.2.1")	GitHub	v2.2.1 · 174/174 · 20M RT
Kotlin	gcf	implementation("com.github.blackwell-systems:gcf-kotlin:2.2.1")	JitPack	v2.2.1 · 174/174 · 10M RT

All six support both encoding profiles:

Feature	Go	TypeScript	Python	Rust	Swift	Kotlin
Graph encode (encode)	✓	✓	✓	✓	✓	✓
Graph decode (decode)	✓	✓	✓	✓	✓	✓
Generic encode (encodeGeneric)	✓	✓	✓	✓	✓	✓
Generic decode (decodeGeneric)	✓	✓	✓	✓	✓	✓
Session deduplication	✓	✓	✓	✓	✓	✓
Delta encoding	✓	✓	✓	✓	✓	✓
Flatten opt-out (noFlatten)	✓	✓	✓	✓	✓	✓
Streaming encode (StreamEncoder)	✓	✓	✓	✓	✓	✓
Thread-safe Session	✓	n/a	✓	✓	✓	✓
CLI	✓	✓	✓	✓	✓	✓
GitHub	gcf-go	gcf-typescript	gcf-python	gcf-rust	gcf-swift	gcf-kotlin
Registry	pkg.go.dev	npm	PyPI	crates.io	SPM	JitPack
API Docs	Go API	TypeScript API	Python API	Rust API	Swift API	Kotlin API

MCP Proxy

Bidirectional proxy for any MCP server: local or remote, stdio or HTTP. Zero code changes required. Session dedup, streaming progress, and HTTP/SSE frontend built in.

pip install gcf-proxy          # PyPI
npm install -g @blackwell-systems/gcf-proxy   # npm
go install github.com/blackwell-systems/gcf-proxy@latest   # Go

gcf-proxy your-mcp-server                                   # local stdio
gcf-proxy --upstream http://host:3000/mcp                    # remote HTTP
gcf-proxy --http :9090 --session your-mcp-server             # deploy as HTTP service

Your server keeps outputting JSON. The LLM receives GCF. Full setup guide.

GitHub · PyPI · npm

Editor Support

Editor	Install	Source
VS Code	Marketplace	gcf-vscode
JetBrains	Marketplace	gcf-jetbrains
Neovim, Helix, Zed	tree-sitter	tree-sitter-gcf

Output compatibility

All implementations produce byte-for-byte identical output for the same input. The format is the product, not the implementation. Token efficiency numbers are independent of which library you use.

Community Implementations

Language	Repository	Maintainer	Status
	Your implementation here

Building an implementation? See the contribution guide. Validate against the 174 conformance fixtures, then PR a link here.