ctx — anti-tokens CLI for Claude Code

Analyze your codebase locally. Feed Claude dense summaries, not raw files.

Status: alpha — under active development. Interfaces will change.

Why

Every token Claude reads costs money and burns context window. When working on a large C# or React codebase, Claude often spends thousands of tokens just reading files to build a mental model before doing any actual work.

ctx runs locally, analyzes your project with language-aware tools (Roslyn for C#, tree-sitter for TypeScript), and emits compact markdown summaries that give Claude everything it needs in a fraction of the tokens.

Installation

go install github.com/ricarneiro/ctx/cmd/ctx@latest

Requires Go 1.22+. Binaries for common platforms will be published after the MVP is validated.

Usage

# Git context: recent commits, status, branch info
ctx git

# Auto-detect stack and emit project overview
ctx auto project

# C# project structure (requires .NET SDK)
ctx csharp project

# C# file outline: types, methods, signatures
ctx csharp outline src/MyService.cs

# List compilation errors
ctx csharp errors

All output is UTF-8 markdown on stdout. Pipe it where you need it:

ctx csharp project | pbcopy   # macOS
ctx csharp project | clip     # Windows

Or reference it in a CLAUDE.md:

Run `ctx csharp project` to get the project overview before making changes.

Architecture

ctx uses a plugin system. Each stack (git, csharp, react, auto) is a plugin that implements the core.Plugin interface and registers itself via init().

core.Plugin interface
  Name() string
  Version() string
  ShortDescription() string
  Command(ctx *core.Context) *cobra.Command

In the MVP, plugins are compiled into the binary. Future plan: migrate to subprocess dispatch (binaries named ctx-csharp, ctx-react in PATH), same pattern as kubectl plugins.

C# analysis uses a separate helper process (tools/roslyn-helper/) written in C# with Roslyn. The helper communicates with ctx via JSON-RPC over stdin/stdout. This lets us use the best tool for the job without pulling a .NET runtime into the Go binary.

See docs/DECISIONS.md for the full rationale behind each architectural choice.

Development

Prerequisites

• Go 1.26+
• .NET SDK 10.0+ (for Roslyn helper)
• golangci-lint (go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest)

Build

go build -o ctx.exe ./cmd/ctx

Tests & lint

go vet ./...
golangci-lint run ./...

Pre-commit hooks

git config core.hooksPath .githooks
# On Linux/macOS also: chmod +x .githooks/pre-commit

Roslyn helper

cd tools/roslyn-helper
dotnet publish src/RoslynHelper -c Release -r win-x64 --self-contained false -o publish/

Contributing

Contributions welcome. See CONTRIBUTING.md (coming soon) for guidelines. Open an issue first if you plan a large change.

License

MIT — see LICENSE.