rtk

Agent-agnostic token optimization: compress, route, filter, and more. One composable pipeline across everything your AI agent reads and sends — built on RTK's battle-tested bash-output compression (up to 90% smaller).

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rtk filters and compresses command outputs before they reach your LLM context. Single Rust binary, 100+ supported commands, <10ms overhead.

What RTK Does

RTK intercepts shell commands and compresses their output before your agent reads it.

How Savings Work

RTK reduces the bash output your agent reads. That is what RTK measures, and it is not the same as cutting 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.

The token counts RTK reports are estimated as bytes / 4 — RTK ships no tokenizer, so the percentages are reliable but the absolute token numbers are approximate.

Full explanation: How RTK Savings Work

Installation

brew install rtk                                              # macOS / Linux
winget install rtk-ai.rtk                                     # Windows
curl -fsSL https://raw.githubusercontent.com/rtk-ai/rtk/refs/heads/master/install.sh | sh

Then check you have the right package — another project named "rtk" exists on crates.io:

rtk --version   # any current version
rtk gain        # must show the savings dashboard, not "command not found"

Cargo, pre-built binaries, native Windows, WSL, and uninstall: Installation guide

What You Install

RTK ships as three downloads. The two rtk editions install a binary with the same name — hooks, scripts and agent config work unchanged across both — so they cannot be installed together. Uninstall one before installing the other.

flowchart TD
    agent["Your coding agent"]

    subgraph editions["Pick one · both install a binary named rtk"]
        direction LR
        full["<b>rtk</b><br/>Apache-2.0 + BUSL-1.1<br/>hooks · filters · engine"]
        oss["<b>rtk-oss</b><br/>Apache-2.0 only<br/>hooks · filters"]
    end

    proxy["<b>rtk-proxy</b><br/>BUSL-1.1<br/>compresses API traffic"]

    agent -->|"command output"| full
    agent -->|"command output"| oss
    agent -.->|"API traffic"| proxy

    classDef apache stroke:#2da44e,stroke-width:2px,fill:none
    classDef busl stroke:#0969da,stroke-width:2px,fill:none
    classDef mixed stroke:#8250df,stroke-width:2px,fill:none
    classDef plain stroke:#8c959f,stroke-width:1px,fill:none
    class full mixed
    class oss apache
    class proxy busl
    class agent plain
    style editions fill:none,stroke:#d0d7de,stroke-dasharray:4 4

Production use is free, engine and daemon included. What the BUSL grant does not cover is offering RTK or a derivative to third parties as a commercial product or service — for that, contact contact@rtk-ai.app.

curl -fsSL .../install.sh | RTK_EDITION=oss sh    # Apache-2.0 edition
brew install rtk-ai/tap/rtk-oss

What the Apache-2.0 edition omits and where the licence boundary falls: Editions and Licensing

Quick Start

# 1. Install for your AI tool
rtk init -g                     # Claude Code / Copilot (default)
rtk init -g --gemini            # Gemini CLI
rtk init -g --codex             # Codex (OpenAI)
rtk init -g --agent cursor      # Cursor
rtk init -g --agent windsurf    # Windsurf
rtk init --agent cline          # Cline / Roo Code
rtk init --agent kilocode       # Kilo Code
rtk init --agent antigravity    # Google Antigravity
rtk init --agent kimi           # Kimi AI
rtk init -g --agent pi          # Pi
rtk init --agent omp            # Oh My Pi (OMP)
rtk init --agent hermes         # Hermes
rtk init -g --agent droid       # Factory Droid
rtk init --agent trae           # Trae (project: .trae/hooks.json)
rtk init -g --agent trae        # Trae global: ~/.trae and existing ~/.trae-cn

# 2. Restart your AI tool, then test
git status  # Automatically rewritten to rtk git status

The agent receives compact output without ever calling rtk explicitly.

The hook only fires on Bash tool calls. Built-in tools like Read, Grep and Glob do not pass through it. Use shell commands (cat, rg, find) or call rtk read, rtk grep, rtk find directly.

Per-agent setup, --dry-run, and uninstall: Quick Start · Supported Agents

How It Works

  Without rtk:                                    With rtk:

  Claude  --git status-->  shell  -->  git         Claude  --git status-->  RTK  -->  git
    ^                                   |            ^                      |          |
    |         full raw output           |            |  compact output      | filter   |
    +-----------------------------------+            +------- (filtered) ---+----------+

Four strategies applied per command type:

1. Smart Filtering - Removes noise (comments, whitespace, boilerplate)

2. Grouping - Aggregates similar items (files by directory, errors by type)

3. Truncation - Keeps relevant context, cuts redundancy

4. Deduplication - Collapses repeated log lines with counts

Does RTK break Claude's prompt cache? No. RTK filters output once per command. The result is stored in history and cached normally on subsequent API calls, so the cache keeps working as expected. Smaller outputs also mean cheaper cache writes and reads. See Troubleshooting for details.

Supported AI Tools

RTK supports 18 AI coding tools. Each integration rewrites shell commands to rtk equivalents, reducing the bash output the agent reads where the agent supports command interception.