RTK (Rust Token Killer) is a command-line tool from RTK AI Labs that reduces the tokens an AI coding agent reads. Tokens are the units of text that a language model is paid by. RTK is a proxy, a program placed between the agent and the shell: it intercepts shell commands and compresses their output before the agent reads it.
A hook rewrites a command such as git status to rtk git status. For more than 100 commands RTK removes noise, groups similar lines, truncates and deduplicates: a test run shows only the failures, and git log shows only hash, author and subject. The project reports 56% less command output on average. RTK Engine can also send large file reads to a cheaper model.
RTK is a single Rust binary, free to use. The command-line tool is open source under the Apache 2.0 license; the compression engine and the optional proxy use the Business Source License 1.1, which allows free production use but not resale as a service.