`CLAUDE.md`

A router, not a home. Claude Code loads this file first, and its job is to send the agent to AGENTS.md and to state the one rule that has to arrive before anything else: check whether a skill owns this request before acting on it.

If your agent is Cursor, Codex or something else, this file is not the one it loads - but the pattern is. Whatever your tool reads first carries the same two sentences.

What goes in here

Almost nothing, and that is the design:

read AGENTS.md first, it is the source of truth
check the skills before acting, and check them again when the work is done
the note that .standards-version records a bookmark rather than a version you are held at

What does not go in here

Any rule. Conventions, red flags, commands, the branching model - all of it lives in AGENTS.md. A rule written here applies to Claude Code and to nothing else, so the repo starts behaving differently depending on which tool somebody opened, with no visible cause.

This is the most common way a repo's instructions rot, and it does not look like rot while it happens. It looks like being helpful to the tool you happen to use.

Why the skills reminder is here and not only in AGENTS.md

Because it is the one instruction that must land before the agent forms a plan. Everything else can be read when it becomes relevant; "is there a procedure for this" stops being answerable once the agent has already started doing it its own way.

The reminder is deliberately repeated at the end, too: the closing steps are the ones most easily skipped - reconciling the spec against what you built, filing what you noticed and did not do, reviewing your own diff before pushing.

Decisions behind it

Routers point, they never hold. The alternative is a per-tool instruction file with real content in it, which is what most repositories have and why their rules quietly disagree.
The skills rule is stated twice, on purpose. Repetition is normally a defect in this standard. Here it is load-bearing, because the two moments it addresses - before starting, after finishing - are far enough apart that one statement covers only the first.

Reference

Status. Optional - part of the core profile.
How it arrives. merge - combine the standard's content with what the repo already has, keeping both (ignore files, CI that already has jobs)
Shipped form. read it in the standard's own tree

The rule that requires it

A repo MUST carry AGENTS.md at its root as the single entry point for

See it in the spec