Every AI coding agent reads an instruction file — AGENTS.md, CLAUDE.md, or a system prompt. Most are copy-pasted and half-stale. Groundrules is a visual builder for them: drag battle-tested blocks (conventions, workflows, hard rules with verification probes) onto a canvas, compile to any target your tools read, then Test Drive against 12+ live models (Claude, GPT, Gemini, Grok…) to see whether the agent actually obeys — before you commit the file. Core builder is free.