ctx

Local-first, pure-Rust MCP context engine for TypeScript/JS/CSS/HTML codebases.

ctx watches your source tree, extracts symbols via tree-sitter, embeds them with a local model, and serves results through the Model Context Protocol so editors and AI agents can query your codebase without sending code to the cloud.

Phase 1: local-only, TS/JS/CSS/HTML support only. Not yet suitable for production use.

Install (macOS, Apple Silicon)

curl -L https://github.com/CodeWithBryan/context/releases/latest/download/ctx-latest-aarch64-apple-darwin.tar.gz | tar xz -C /usr/local/bin ctx

Binaries are Developer ID signed + notarized — no Gatekeeper workaround needed. Intel Macs and Linux are out of scope for Phase 1.

First run

cd my-project
ctx init .
ctx index .      # first time: ~150 MB model download + ~7 min indexing

Wire it into your agent

Claude Code

claude mcp add ctx -- ctx serve .

Codex CLI

codex mcp add ctx -- ctx serve .

Both commands register ctx as a stdio MCP server scoped to the current repo. Run them from the project root after ctx init . + ctx index ..

Update

ctx update --force

Benchmark

A/B bench: runs fixed question set through claude --print twice — once with no MCP, once with ctx — and compares wall time, tokens, cost.

Requires: bun, claude, ctx in PATH. Target repo already indexed (ctx init . && ctx index .).

# defaults: 5 built-in questions, 1 run, concurrency 4
bun run scripts/bench-ctx.ts ~/path/to/repo

# custom questions file (one per line, `#` comments ignored), 3 runs averaged,
# serial (concurrency 1 = most stable numbers)
bun run scripts/bench-ctx.ts ~/path/to/repo \
  --questions scripts/bench-questions.txt \
  --runs 3 \
  --concurrency 1

Prints a markdown table per question + totals (wall clock, input/output tokens, USD). Kill any running ctx serve before starting — the bench spawns its own shared HTTP server so the embedder loads once.

Status

Phase 1 MVP is complete and verified end-to-end. See the implementation plan for scope and known limitations: docs/superpowers/plans/2026-04-19-ctx-phase1-mvp.md

Full install options and MCP config JSON: INSTALL.md