GCF - Graph Compact Format

Syntax highlighting for GCF, the AI-native wire format for structured data. 71% fewer tokens than JSON.

Features

• Full syntax highlighting for .gcf files
• Supports both generic and graph profiles
• Highlights all GCF constructs:
  • Headers: GCF profile=generic, GCF profile=graph tool=...
  • Section headers: ## name, ## name [N]{field1,field2}
  • Summary trailers: ##! summary counts=N,M
  • Comments: # comment text
  • Symbol IDs: @0, @1, @123
  • Edge notation: @0<@1 calls, @1>@0 references
  • Key-value pairs: key=value
  • Scalars: numbers, booleans (true/false), null (-), absent (~)
  • Quoted strings: "hello world" with escape sequences
  • Pipe separators: tabular row delimiters
  • Attachments: ^, ^{fields}, .fieldname {}

Installation

From VSIX (local install)

1. Download the .vsix file from the releases page
2. In VS Code, open the Command Palette (Ctrl+Shift+P / Cmd+Shift+P)
3. Run Extensions: Install from VSIX...
4. Select the downloaded .vsix file

From Marketplace

Search for "GCF" in the VS Code Extensions panel.

From source

git clone https://github.com/blackwell-systems/gcf-vscode.git
cd gcf-vscode
npm install -g @vscode/vsce
vsce package
code --install-extension gcf-vscode-0.1.0.vsix

What is GCF?

GCF (Graph Compact Format) is a token-optimized wire format designed for LLM tool responses. It encodes structured data (objects, arrays, tables, graphs) using 71% fewer tokens than JSON at scale.

• Generic profile: Lossless round-trip encoding for any JSON-compatible data
• Graph profile: Specialized encoding for code graphs with symbol IDs and edges

Learn more at betterthanjson.com or read the specification.

License

MIT. Copyright (c) 2026 Blackwell Systems.