fathom-custodian

Register falsifiable concerns about a repo's agent configuration (CLAUDE.md / AGENTS.md) and act on fathom config audit violations — the "instructed means true" loop, where fathom is the instrument and THIS session is the hand. Use when config feels stale, after a doctor concerns failure or a session-start config attention line, when asked to "keep CLAUDE.md honest", or to set up config contracts in a newly wired repo.