rtk — Rust Token Killer (token discipline)

A single Rust binary that filters and summarises command output before it hits the LLM context. ~80% fewer tokens on common dev commands, <10ms overhead, 100+ commands. Apache-2.0. Directly serves token-reduction doctrine.

Install

brew install rtk                                  # macOS
curl -fsSL https://raw.githubusercontent.com/rtk-ai/rtk/refs/heads/master/install.sh | sh   # Linux/macOS -> ~/.local/bin
rtk --version

Use it (prefix the command)

rtk ls            rtk tree           rtk read <file>        # token-optimized read/list
rtk git status    rtk git diff       rtk git log            # compact git
rtk grep <pat>    rtk find -name x   rtk diff a b           # condensed search/diff
rtk test          rtk err <cmd>                             # tests: only failures; cmd: only errors/warnings
rtk gh ...        rtk docker ...     rtk psql ...           # compact gh/docker/db
rtk json <file>   rtk env            rtk deps               # compact json/env/deps

rtk smart gives a 2-line technical summary of output.

Automatic mode (recommended for agents)

rtk init -g       # installs a global hook so common commands route through rtk automatically

Without the hook, just prefix manually with rtk.

When to use

• DEFAULT for any read-only inspect command whose raw output is large (file reads, listings, grep, git status/diff/log, test runs, logs, docker ps, json).
• Pairs with token discipline: reference-over-inline, deltas-over-dumps — rtk enforces it at the shell layer.
• Not for commands whose full output you genuinely need verbatim (then run the raw command).

Verified

Tested on macOS (rtk 0.42.4): rtk git status, rtk ls return compact output correctly.