Startup hooks in data-platform and pr-review were checking for venvs
at the marketplace path (~/.claude/plugins/marketplaces/.../mcp-servers/)
which gets wiped on updates. The actual venvs live in the cache directory
(~/.cache/claude-mcp-venvs/) which survives updates.
This caused false "MCP venv missing" errors even when venvs existed,
wasting hours of debugging time.
Fixed hooks now check cache path first, matching the pattern used
by run.sh scripts.
Also updated docs/CANONICAL-PATHS.md with the correct venv path pattern
to prevent future occurrences.
Lesson learned: lessons/patterns/startup-hooks-must-check-venv-cache-path-first
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
