# ctx

> ctx makes AI coding agents read less. Have them call ctx instead of cat, grep, find and git log: it keeps structure and line numbers and folds the rest. Measured on the public repo rtk-ai/rtk (tag dev-0.50.1-rc.456, wc -c from the repo root): 84.2–96.6% fewer output bytes. Made by Ferrorium (https://ferrorium.com/). Version 0.1.0. macOS (arm64, x86_64) and Linux (x86_64, arm64). Prebuilt binaries only; source is private.

Last updated: 2026-10-04

## Install

```sh
curl -fsSL https://ctx.ferrorium.com/install.sh | sh
```

- Installs to ~/.local/bin/ctx and verifies SHA-256.
- Env: CTX_VERSION (default latest, e.g. v0.1.0), CTX_INSTALL_DIR (default ~/.local/bin).
- If `ctx: command not found`: export PATH="$HOME/.local/bin:$PATH"
- Uninstall: rm ~/.local/bin/ctx
- Windows: no native build; WSL installs the Linux binary.

## Agent rules (paste into CLAUDE.md or AGENTS.md)

```
## Search & Read
- cat -n        → ctx outline <file>
- sed -n A,Bp   → ctx read f1 A-B f2 A-B
- grep / rg     → ctx grep <pat> <ROOT>
- find          → ctx map <ROOT>
- session start → ctx brief <ROOT>
- build / test  → ctx wrap -- <cmd>
- web search    → ctx web "<query>"
- read a page   → ctx fetch <url>
Batch many files and patterns into one call.
```

## Commands

- `ctx outline` (replaces cat -n): Signatures with line numbers. Bodies are elided, and gaps show as line jumps.
- `ctx grep` (replaces grep -rn · rg): Grouped by file, duplicate lines folded, per-file cap. Supports -E -i -w -C -l -e; literal by default.
- `ctx read` (replaces sed -n A,Bp): Read line ranges from many files in one call.
- `ctx def` (replaces grep + read): A symbol's definition through the end of its block.
- `ctx map` (replaces find · ls -R): Extension histogram and largest directories, for several roots at once.
- `ctx brief` (replaces git status + log + ls): One screen at session start: branch, changed files, recent commits, file mix.
- `ctx wrap` (replaces cmd | tail): Runs a build or test, compresses the output, keeps the exit code.
- `ctx web · fetch` (replaces 웹 검색 · 페이지 읽기): Metasearch over Brave and Bing, plus readable page bodies as markdown. No API key.

## Benchmark (output bytes, lower is better)

| ctx | baseline | before | after | change |
|---|---|---|---|---|
| ctx grep | grep -rn | 487,192 B | 53,762 B | -89.0% |
| ctx outline | cat -n | 190,645 B | 20,947 B | -89.0% |
| ctx map | find | 20,705 B | 705 B | -96.6% |
| ctx brief | git status + log | 9,231 B | 1,460 B | -84.2% |

Results vary by codebase. Part of the grep gain comes from the per-file cap.

## Downloads (v0.1.0)

- macOS Apple Silicon: https://ctx.ferrorium.com/dl/v0.1.0/ctx-aarch64-apple-darwin.tar.gz (sha256 c0bccbd9e01f9ca3a8ca5d71f8ea7fdafefd58c8de300904c567b08760e5fa6a)
- macOS Intel: https://ctx.ferrorium.com/dl/v0.1.0/ctx-x86_64-apple-darwin.tar.gz (sha256 ecc96e852a412f0a985394c0d6ed7511dff65b6bcce57157f82430f57c441c9a)
- Linux x86_64: https://ctx.ferrorium.com/dl/v0.1.0/ctx-x86_64-unknown-linux-musl.tar.gz (sha256 778f61b16b5d1c0c65769bd498141f1bff2008614033b350b1633ba6fe60cd91)
- Linux arm64: https://ctx.ferrorium.com/dl/v0.1.0/ctx-aarch64-unknown-linux-musl.tar.gz (sha256 95dbbc063175689517906849c55d535663cda2918446ddfe09be86f9ba972277)
- Latest alias: https://ctx.ferrorium.com/dl/latest/ctx-<target>.tar.gz

## Links

- Install script: https://ctx.ferrorium.com/install.sh
- All Ferrorium products: https://products.ferrorium.com/
- Ferrorium (AI engineering company): https://ferrorium.com/
- Contact: wks0968@gmail.com