I saved 10M tokens (89%) on my Claude Code sessions with a CLI proxy

[muskiness]

Feature Request: Built-in CLI output filtering/compression to reduce token usage (inspired by RTK)

Hey team! 👋

I recently came across an interesting project called [RTK (Rust Token Killer)](https://github.com/rtk-ai/rtk) — a CLI proxy that filters and compresses command output before it reaches the LLM context. The author shared their results on [Reddit](https://www.reddit.com/r/ClaudeAI/comments/1r2tt7q/i_saved_10m_tokens_89_on_my_claude_code_sessions/), and the numbers are impressive:

• cargo test: 155 lines → 3 lines (98% reduction)
• git status: 119 chars → 28 chars (76% reduction)
• git log: compact summaries instead of full output
• Total savings over 2 weeks: ~10M tokens (89%)

The core idea is simple: most CLI output sent to the LLM is noise — passing tests, verbose logs, progress bars, redundant formatting. Stripping that out before it hits the context window saves a massive amount of tokens without losing any useful information.

Why this would be valuable as a built-in feature in your project:

1. Users wouldn't need to install and configure a separate tool
2. Filtering rules could be context-aware and tightly integrated with your existing command execution pipeline
3. It directly reduces costs and improves response quality (less noise = better reasoning)
4. It could be opt-in with sensible defaults

Possible implementation scope:

• Configurable output filters for common commands (git, npm, cargo, pip, test runners, etc.)
• Smart truncation with summary (e.g., "47 tests passed, 2 failed" instead of full test output)
• User-defined rules for custom commands
• Toggle on/off per session or globally

I think this kind of optimization would be a huge quality-of-life improvement for users and a natural fit for your tool. Would love to hear your thoughts on whether this is something you'd consider exploring!

References:

• RTK repo: https://github.com/rtk-ai/rtk
• RTK site: https://www.rtk-ai.app
• Reddit discussion: https://www.reddit.com/r/ClaudeAI/comments/1r2tt7q/