rtk hit 75,000 stars compressing shell output before the agent reads it, and its README admits output reduction isn't bill reduction.

v0.28.2, single Rust binary, zero dependencies, intercepting 100+ common dev commands (git, cargo, docker, test runners) and filtering their output before it enters context, claiming up to 90% reduction on test-runner output and ~80% on cargo builds. The honest part is what earns the attention: the README explicitly separates output reduction from cost reduction, noting bash output is one component of input tokens alongside prompts and conversation history, so savings dilute across the bill. 74,979 stars, 1,451 commits. That kind of README honesty is rare enough to be a purchase signal.