Skill Doctor

skill-doctor

Every auto-invocable skill injects its name + description into every single request, whether it ever fires or not. With a large library that is a constant, invisible token tax. Claude Code surfaces this only per-plugin (/plugin) and never flags trigger collisions — so standalone skills are a blind spot. skill-doctor closes it: measure the tax, find dead weight, find collisions, and produce concrete, reversible fixes.

All logic is in scripts/ (Python stdlib only — no dependencies). The scripts emit deterministic JSON facts; the one judgment call (confirming collisions) is yours, made from the shortlist.

When to use

• "audit my skills", "why is my context so big", "prune unused skills"
• after installing a skill pack / many plugins
• to find duplicate or conflicting skills

Workflow

Path setup (required). Skills run from the user's working directory, not from the skill folder — so invoke the scripts by their absolute path. Set SKILL_DIR to this skill's base directory (the harness states it as "Base directory for this skill: " when the skill loads; otherwise it's the directory you read this SKILL.md from, e.g. ~/.claude/skills/skill-doctor). The --out-dir is relative to the user's cwd, which is what you want.

SKILL_DIR="<absolute dir of this SKILL.md>"
python "$SKILL_DIR/scripts/run.py" --live --out-dir ./skill-doctor-out

--live pulls the authoritative loaded set + exact injected payload from the most recent transcript. Outputs: scan.json, usage.json, collide.json, report.md, actions.json. A one-line SUMMARY prints to stdout.

Then:

1. Read report.md and present the headline (tokens/turn), the disable candidates with projected savings, the collision shortlist, and staleness.
2. Judge collisions. Open collide.json. For each candidate pair, read both full descriptions and decide if they would genuinely both auto-trigger on the same request. Keep only the real ones; recommend merging or sharpening the loser's description.
3. Propose fixes, then on the user's OK apply them (reversible):

# dry-run first (default), then --write
python "$SKILL_DIR/scripts/apply.py" --from-actions ./skill-doctor-out/actions.json --write
# undo anything:
python "$SKILL_DIR/scripts/apply.py" --names skill-a,skill-b --revert --write

apply.py only edits user/project SKILL.md frontmatter (never plugin/bundled skills), writes a .bak, and is fully reversible.

Optionally also flag unused MCP servers:

python "$SKILL_DIR/scripts/mcpusage.py"

Individual tools

All invoked as python "$SKILL_DIR/scripts/<tool>.py" --help:

• scan.py — inventory + per-skill cost + staleness (--live / --listing FILE / --exact)
• usage.py — per-skill firing history from transcripts (--days N)
• collide.py — trigger-collision shortlist (--threshold, overlap-coefficient)
• compress.py — flag verbose descriptions to slim (keep the skill, cut its cost)
• report.py — merge into report.md + actions.json (--ignore a,b to allowlist skills)
• apply.py — apply/revert disable-model-invocation (guarded)
• mcpusage.py — flag configured-but-never-used MCP servers (~/.claude.json + transcripts)
• context.py — unified always-on context budget (skills + CLAUDE.md + rules), ranked
• monitor.py — record per-session skill usage durably (--latest from a SessionEnd hook; --summary)
• lint.py — score a candidate skill before adding it (--path SKILL.md: cost, collision risk, routing)
• evalgate.py — generate trigger probes (--name/--path) to confirm a change didn't break routing

The report also flags budget (over Claude Code's skillListingBudgetFraction, descriptions get silently dropped) and lists compress candidates — skills to keep but whose descriptions are verbose. To compress one: draft a shorter routing-correct description (keep the trigger words/phrases that make Claude auto-invoke it; cut prose/examples), then apply it with the verify gate — it refuses the change unless the new text is shorter and still contains those trigger words:

python "$SKILL_DIR/scripts/apply.py" --set-description pandas-pro \
  --text "Pandas DataFrame ops: cleaning, aggregation, merging, time series." \
  --must-contain "pandas,dataframe" --write
# revert like any change:
python "$SKILL_DIR/scripts/apply.py" --names pandas-pro --revert --write

Notes

• Token figures are offline estimates (~4 chars/token); percentages are tokenizer-independent. For exact absolute counts, set ANTHROPIC_API_KEY and add --exact (uses the count_tokens API; falls back to the estimate if no key).
• The report states a confidence line — how many days of transcript history back the "never fired" calls. More history = stronger recommendation.
• paths-scoped skills (frontmatter paths:) load only for matching files, so they are excluded from the always-on tax and never proposed for disabling.
• Likely duplicates (near-identical descriptions) are reported separately from trigger collisions — one of a duplicate pair is usually removable.
• --grace-days N (default 0/off) excludes never-fired skills modified within N days. Off by default because file mtime is unreliable on synced machines.
• Disabling a skill (disable-model-invocation: true) only stops automatic invocation — you can still run it manually with /name.
• The verified mechanics this skill relies on are documented in references/mechanics.md.