index.md

title	RTK Documentation
description	RTK (Rust Token Killer) — cut the bash output your agent reads on common dev commands, with zero workflow changes
sidebar	order 1

RTK — Rust Token Killer

RTK is a CLI proxy that sits between your AI assistant and your development tools. It filters command output before it reaches the LLM, keeping only what matters and discarding boilerplate, progress bars, and noise.

Result: fewer bash output bytes reaching the LLM per command, without changing how you work. You run git status as usual — RTK's hook intercepts it, filters the output, and the LLM sees a compact 3-line summary instead of 40 lines.

How it works

Your AI assistant runs:  git status
                              ↓
              Hook intercepts (PreToolUse)
                              ↓
              rtk git status  (transparent rewrite)
                              ↓
     Raw output: 40 lines     →     Filtered: 3 lines
                              ↓
              LLM sees the compact output

Zero config changes to your workflow. The hook handles everything automatically.

What the savings mean

RTK reduces bash output bytes — the output a shell command sends back before your agent reads it. That is not the same as reducing your bill by the same amount.

Bash output is one contributor to input tokens, alongside your prompt, the system prompt and conversation history. Input tokens are in turn only part of the bill, which also counts output tokens. The reduction dilutes at every step.

See How RTK Savings Work for the full picture, including why the token counts RTK reports are estimates.

What RTK optimizes

Dozens of commands across all major ecosystems — Git, Cargo/Rust, JavaScript, Python, Go, Ruby, .NET, Docker/Kubernetes, and more. See What RTK Optimizes for the full list.

Get started

1. Installation — Install RTK and verify you have the right package
2. Quick Start — Connect to your AI assistant in 5 minutes
3. Supported Agents — Claude Code, Cursor, Copilot, Gemini, and more

Measure your savings

rtk gain           # total savings across all sessions
rtk gain --daily   # day-by-day breakdown
rtk gain --weekly  # weekly aggregation

See Token Savings Analytics for export formats and analysis workflows.

Analyze your usage

rtk discover       # find commands that ran without RTK (missed savings)
rtk session        # RTK adoption rate per Claude Code session

See Discover and Session for details.

Go further

Two optional layers sit on top of the hooks. Neither changes anything until you opt in.

• The engine — everything RTK does is expressed in one composable pipeline.toml: which commands get rewritten, what happens to a tool's output, what the proxy compresses. With no pipeline file you are on rtk:default and nothing changes. Start with Writing a Pipeline; Conditions and Judges and Methods are the vocabulary, Pipeline Commands is for inspecting, debugging and sharing one.
• The RTK Proxy — a local daemon that runs the pipeline on the API traffic itself, one layer above bash output. Ships as its own download. See What the Proxy Compresses and Proxy Configuration.

Further reading

• Configuration — config.toml, global flags, env vars, recall recovery
• Troubleshooting — common issues and fixes
• Telemetry & Privacy — what RTK collects and how to opt out
• Agent Coverage — what each agent's hook API lets RTK do
• Editions and Licensing — the three downloads, what each contains, where the licence boundary falls
• ARCHITECTURE.md — system design for contributors