← kerf.boxopen the app →
⎯ Pricing

It’s free.
You bring the key.

kerf.box runs on whatever AI provider you already use — Claude, OpenAI, Gemini, Kimi, Qwen, DeepSeek, Groq, OpenRouter, even a local Ollama. Bring your own key (or connect it to your agent over MCP) and it’s free, forever. We never charge you, and we never run generation on our own key — every live run is yours, billed to your own provider account. No subscriptions, no metering, no per-seat math.

Free
$0/ forever

Bring a key from any AI provider, or connect via MCP. You only ever pay your provider for the tokens you use.

  • ▪Kerfs on your own key — Claude, OpenAI, Gemini, Kimi, Qwen, DeepSeek, Groq, OpenRouter, Ollama, or any custom endpoint
  • ▪Or connect it to Claude over the MCP server — no key to paste
  • ▪Full REST API + MCP server for agents — no account, no API key
  • ▪Save kerfs in your browser; export & import as JSON to share
  • ▪No sign-up — every page is public
  • ▪The refusal engine — undefendable strategy is rejected
  • ▪Open source. Self-host the whole thing.
Start free →

Your key lives only in your browser and is sent to our API as a single per-request header — never stored, logged, or proxied. Building an agent or self-hosting? Point the API or MCP server at your own key — we add no metering (only a per-IP abuse cap); the only bill is your own provider usage. See the source →