**A cyclic YAML alias crashed the tool.** `meta: &m [*m]` parses cleanly into
a self-referential array, and the frontmatter comparison is a recursive walk,
so a hostile server could take down `--verify` or the TUI with a stack
overflow instead of receiving a finding. Verified before fixing: it really
did raise `RangeError: Maximum call stack size exceeded`.
Rejected at the parse, so no consumer has to be cycle-safe on its own, and it
becomes an ordinary `frontmatter-unparsable` finding. Detection is per-PATH
rather than per-graph — `seen` unwinds on the way back up — so an alias reused
across siblings, which is ordinary YAML and represents fine in JSON, is not
mistaken for a cycle. A depth bound closes the same hole by its other door: a
legal, acyclic but absurdly nested document exhausts the stack just as well,
and a cycle check alone passes it.
**The web frontmatter check was gated on the presentation MIME.** It ran off
`previewParts`, which exists only when the displayed type is recognized as
markdown — so a `SKILL.md` a server typed `text/plain`, or served as a base64
blob, skipped a mandatory comparison while the pane still read as clean. It
now decodes the same fetched bytes the digest is taken over, which also stops
the two answers describing different derivations of the payload.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ND46Ci64DC3tzBy9aG81Nc
Signed-off-by: cliffhall <cliff@futurescale.com>
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