RTK (Rust Token Killer)
Command-line proxy (a single Rust binary, zero dependencies) that compresses shell command output before it reaches your agent context. The principle: when Claude Code runs `git log`, `pytest` or `tsc`, the raw output weighs thousands of tokens of which the agent uses a fraction. RTK filters and condenses that output on the fly (100+ commands covered) with under 10 ms overhead. It installs with one curl command, then `rtk init -g` sets a Claude Code hook that automatically rewrites Bash commands to their rtk equivalents. Claims 60 to 90% fewer tokens on common dev commands.
Strengths
- Attacks the cost line nothing else shrinks: command outputs reread by the agent
- A single Rust binary, zero dependencies, under 10 ms overhead per command
- Installs as a global hook once, then transparent: no change in how you prompt
Limitations
- The 60-90% figures come from the vendor; the real gain depends on your command mix
- A filter between agent and terminal: overly aggressive compression can hide a useful signal
Best for
- A dev on a quota Claude plan whose sessions die on verbose test suites
- A CI agent replaying the same verification commands dozens of times a day