Implementations
Seven official implementations, all Apache-2.0 licensed and zero runtime dependencies. The current spec v3.5.3 contract is defined by 281 conformance fixtures. All seven implementations pass 281, with 43B+ combined round-trips verified.
Official Implementations
| Language | Package | Install | Registry | Status |
|---|---|---|---|---|
| Go | gcf-go | go get github.com/blackwell-systems/gcf-go@v1.7.1 | pkg.go.dev | v1.7.1 · 281 · 1B+ RT |
| TypeScript | @blackwell-systems/gcf | npm install @blackwell-systems/gcf@2.6.1 | npm | v2.6.1 · 281 · 20M RT |
| Python | gcf-python | pip install gcf-python==2.7.1 | PyPI | v2.7.1 · 281 · 10M RT |
| Rust | gcf | cargo add gcf@3.0.1 | crates.io | v3.0.1 · 281 · 43B+ RT |
| Swift | GCF | .package(url: "https://github.com/blackwell-systems/gcf-swift", from: "2.7.1") | GitHub | v2.7.1 · 281 · 20M RT |
| Kotlin | gcf | implementation("com.github.blackwell-systems:gcf-kotlin:2.6.1") | JitPack | v2.6.1 · 281 · 10M RT |
| .NET | BlackwellSystems.Gcf | dotnet add package BlackwellSystems.Gcf | NuGet | v1.0.0 · 281 · new |
All seven support both encoding profiles:
| Feature | Go | TypeScript | Python | Rust | Swift | Kotlin | .NET |
|---|---|---|---|---|---|---|---|
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 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | n/a |
| GitHub | gcf-go | gcf-typescript | gcf-python | gcf-rust | gcf-swift | gcf-kotlin | gcf-dotnet |
| Registry | pkg.go.dev | npm | PyPI | crates.io | SPM | JitPack | NuGet |
| API Docs | Go API | TypeScript API | Python API | Rust API | Swift API | Kotlin API | .NET 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 # Gogcf-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 serviceYour server keeps outputting JSON. The LLM receives GCF. Full setup guide.
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 281 conformance fixtures, then PR a link here.