Drop your Claude Code session log and find out which of your installed Skills actually fire in practice. Half of installed skills don't activate per session — each unused one burns hundreds to thousands of context tokens.
Claude Code session logs live in ~/.claude/projects/<project-slug>/<session-id>.jsonl. Pick a recent, long session (10K+ lines) for the most representative audit.
Quick shell command to list recent logs:
Or paste log contents below if file upload is awkward:
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Installed skills
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Actually invoked
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Never fired
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Tokens wasted / session
| Skill | Invocations | Estimated tokens loaded | Status |
|---|
This pattern was first surfaced in a r/ClaudeAI post (2026-05) auditing session logs and finding that approximately half of installed Skills never fired — burning roughly 23,000 context tokens per session for the average power user. The mechanism is structural: Claude Code loads every installed skill's instruction text into context at session start, regardless of whether the model auto-activates it.
For the full operator-side cost catalog (13 token-spike patterns including this one, with 800 hours of measured before/after data), see the Token Book on Zenn (¥2,500, ~15 chapters, free preview includes Chapter 1).
For the broader cluster framework (13 structural failure clusters in Claude Code, ~11,800 cumulative GitHub reactions), see the cluster tracker. Skills metadata loading sits in Cluster 7 with this 23K-per-session waste as the operationally-tractable sub-pattern.
For the monthly continuation — newly-found incidents, defensive hooks, safety checklist, archived month-by-month — see CC Safety Lab Founder Membership (¥500/month, locked price for charter members).