Jenny Ouyang's two-month Claude Code bill came to $1,600. She wrote up the autopsy on her Build to Launch Substack , and the diagnosis was unambiguous: the prompts were not the problem. The tool output was. "Every time Claude reads a file, runs a shell command, or calls an MCP server, the full output gets appended to context," she wrote. By message 40 of a session, she was paying for everything that came before — over and over. 📖 Read the full version with charts and embedded sources on ComputeLeap → If you have ever seen Claude Code helpfully run git log only to dump 800 lines of merge commits into its working memory, you already understand the shape of this problem. The fix that the open-source community has rallied around in 2026 is a 4 MB Rust binary called rtk — short for Rust Token Killer. It sits between your AI agent and your shell, intercepting noisy commands and returning compact, LLM-friendly summaries before the bytes ever reach the context window.…