# RTK — CLI Proxy That Cuts LLM Token Usage

> RTK is a single-binary Rust CLI proxy that intercepts common developer commands and compresses their output before it reaches your LLM, reducing token consumption without changing your workflow.

## Install

Save as a script file and run:

# RTK — CLI Proxy That Cuts LLM Token Usage

## Quick Use
```bash
# Install via cargo or download the prebuilt binary
cargo install rtk
# Wrap any command — output is compressed before your LLM sees it
rtk -- ls -la
rtk -- git diff
```

## Introduction
RTK sits between your AI coding agent and the shell, intercepting command output and applying format-aware compression so the LLM receives fewer tokens. It ships as a single Rust binary with zero runtime dependencies, making it trivial to drop into any agentic workflow.

## What RTK Does
- Intercepts stdout/stderr of arbitrary shell commands and rewrites them into a compact representation
- Applies format-specific reducers for JSON, diffs, directory listings, logs, and build output
- Preserves semantic content while stripping redundant whitespace, ANSI codes, and boilerplate
- Works transparently with Claude Code, Codex CLI, and other agentic tools
- Outputs original content when piped to a non-LLM consumer via TTY detection

## Architecture Overview
RTK spawns the target command as a child process, captures its output streams, and passes them through a pipeline of format detectors and compressors. Each compressor is a pure function that pattern-matches on the input structure. The final output is emitted to stdout so the calling agent reads the reduced version. Because it is a thin wrapper with no daemon, startup overhead is sub-millisecond.

## Self-Hosting & Configuration
- Install from source with `cargo install rtk` or grab a static binary from the GitHub releases page
- No configuration file required — sensible defaults cover most use cases
- Set `RTK_PASSTHROUGH=1` to disable compression for debugging
- Custom reducers can be added via a TOML config at `~/.config/rtk/config.toml`
- Integrates with Claude Code by prefixing shell commands or aliasing common tools

## Key Features
- Single static binary, no Python or Node dependency
- Sub-millisecond startup; negligible overhead on command execution
- Format-aware compression preserves meaning while dramatically shrinking output
- TTY detection prevents accidental compression of human-facing output
- Open source under MIT license with active community contributions

## Comparison with Similar Tools
- **LLMLingua** — prompt compression at the model level; RTK compresses at the shell output level before the prompt is built
- **Repomix** — packs entire repos into a single file for context; RTK focuses on individual command output
- **Context window managers** — most operate on chat history; RTK targets raw tool output

## FAQ
**Q: Does RTK change the command's behavior?**
A: No. RTK only post-processes stdout/stderr. The underlying command runs exactly as it would without RTK.

**Q: Which AI agents does it work with?**
A: Any agent that shells out to run commands — Claude Code, Codex CLI, OpenCode, and custom setups.

**Q: Can I disable it for specific commands?**
A: Yes, set `RTK_PASSTHROUGH=1` or use the `--raw` flag.

**Q: Is it safe for production CI pipelines?**
A: RTK is designed for interactive agentic use. In CI, run commands directly without the wrapper.

## Sources
- https://github.com/rtk-ai/rtk
- https://rtk.dev/docs

---
Source: https://tokrepo.com/en/workflows/rtk-cli-proxy-cuts-llm-token-usage-58a018a0
Author: Script Depot