FAQ
Frequently asked questions about Arnold.
What is Arnold?
Arnold is a documentation-first development toolkit. It runs as slash commands inside AI coding agents like Claude Code, Cursor, and Windsurf. The signature feature is drift detection - comparing your docs to your code and telling you where they disagree.
Is Arnold a CLI tool?
No. Arnold is not a standalone CLI. It runs as slash commands inside your existing coding agent. You type /arnold:check in Claude Code the same way you'd type any other slash command. No separate terminal, no separate install.
Does Arnold need an API key?
No. Arnold uses the host agent's context and LLM. No separate API key, no separate billing.
Does Arnold have a database?
No. Arnold is pure markdown files and shell scripts. Your docs are stored as markdown files in a docs/ folder in your repo. Version-controlled with Git like everything else.
What agents does Arnold work with?
Arnold works with Claude Code (native plugin), Cursor, Windsurf, Gemini CLI, Codex, and 30+ other AI coding agents. If your agent can read files and follow instructions, Arnold works with it.
Is Arnold free?
Yes. Arnold is open-source, MIT licensed, and free forever. No premium tiers, no feature gating.
What's the Jurassic Park thing about?
Arnold uses a 🦕 Jurassic Park personality because documentation should be alive, not extinct. The character of Ray Arnold (played by Samuel L. Jackson in the film) is the engineer who tries to keep the park's systems running - a perfect metaphor for keeping docs and code aligned. Plus, "Hold on to your butts" is excellent advice before running a drift check.
How is Arnold different from Notion/Jira/Google Docs?
Those tools live outside your codebase. Arnold puts docs next to your code as markdown files you version-control with Git. More importantly, Arnold checks your docs against your code. Nobody else does that.
Can Arnold write code?
Yes, with /arnold:build. It reads acceptance criteria from your feature docs, builds code to satisfy them, and verifies each criterion with a code citation. But you can also build code any way you like and just use Arnold for drift detection.