If you use Claude Code, Cursor, Copilot, or any other AI coding assistant in your terminal, you are probably spending way more on tokens than you need to. RTK (Rust Token Killer) is an open-source CLI proxy that sits between your shell and your LLM and silently compresses what gets sent to the model — without changing how you work.
It has 39.5k stars on GitHub. It is worth understanding why.
The Problem It Solves
When an AI coding agent runs git status, the raw output can be 2,000 tokens. When it runs cargo test on a mid-sized project and a few tests fail, you are looking at 200+ lines of output — most of it passing tests you do not care about.
The agent reads all of it. You pay for all of it.
