parse_contributing_files documented that callers depend on None vs [], because a
parse failure returning [] would silently disable the check. Only check 8
honoured it; checks 4/5 (skill-audit) and 3/4 (agent-audit) used a truthiness
test, so an unreadable block disabled them without a word.
Two live corpus entries were skipping this way. A sweep of all 32 sources.md
found 134 entries, exactly 2 parsing to None, both in gitea-files: one heading
carried an inline parenthetical that defeated both regexes, and one (none) was
written without its leading bullet. Also pins EMPTY_SOURCE_KEYS_RE to the two
indents parse_source_keys actually reads.
agent-audit had no INFO tier at all, so it gains one rather than reporting a
check that could not run as a FAIL.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EJJrm5YmacbwMdzZpXcoti