I’ve got a pile of skills installed in Claude Code and I started wondering how many actually auto-activate vs. just sit there loading their instructions into context every session. Turns out Claude Code’s session logs ( ~/.claude/projects/*.jsonl ) already record this. Both when a skill gets explicitly invoked, and a per-message “attribution” tag showing which skill was active. So you can reconstruct, per skill: how often it fired, how much it was actually used afterward, when it last activated, and what it costs in context tokens. I pulled mine and it wasn’t pretty. About 4 skills doing real work, about 13 that have never fired once, together loading 23.5k tokens into every single session for nothing. So I built a small CLI/MCP tool to make this a one-liner instead of grepping JSONL by hand: $ skillvitals scan | skill | fires | engaged | ctx | last seen | status | |------------------|-------|---------|------|-----------|-------------| | frontend-design | 31 | 140 | 6.4k | today | healthy | | ab-test-coach | 2 | 2 | 5.7k | 3d ago | misfiring | | data-analysis | 0 | 0 | 4.2k | never | never-fired | | … | | | | | | 3 dormant/never-fired skills are costing you 8.7k tokens per session. It also flags why a skill might not be firing (vague description, no “use when…” trigger phrasing, near-duplicate of another skill, broken frontmatter) and suggests fixes. It shows them, it doesn’t edit your files. A few honest notes: It’s 100% local. Only reads files already on your machine, no uploads, no telemetry. The health labels (dormant/misfiring) are heuristics, not ground truth. The thresholds are in the source if you want to argue with them. It does not generate activation hooks. That space already has good tools (skills-hook, claude-skills-supercharged). This is just the monitoring layer. Install: pip install skillvitals # or: uvx skillvitals scan Repo: https://github.com/PraveenKumarSridhar/skillvitals Genuinely curious what everyone else’s dead-token number is. Drop it in the comments if you run it, and I’ll take feature requests or bug reports here or on GitHub. submitted by /u/praveen1411
Originally posted by u/praveen1411 on r/ClaudeCode