JetBrains benchmark finds RTK token compression tool shows 7.6% cost increase on Claude Code

JetBrains measured Rust Token Killer (RTK), a compression proxy for Claude Code, and found it increased token costs by 7.6 percent at low reasoning effort (p=0.004) and showed no measurable change at high effort, contrary to RTK's advertised 60-90 percent savings, according to the JetBrains AI blog. Task quality remained unchanged in both test arms.

Update (2026-07-29): According to GitHub repositories, ContextSpy and MemU emerged to address token bloat in Claude Code sessions. ContextSpy profiles tool descriptions and API responses to identify token waste by intercepting and visualizing prompt composition across multiple requests. MemU p...