Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/paultaki/claude-skill-usage/skill-usagenpx skills add paultaki/claude-skill-usage --skill skill-usagegit clone --depth 1 https://github.com/paultaki/claude-skill-usageWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/paultaki/claude-skill-usage/skill-usage)<a href="https://agentmods.dev/skills/paultaki/claude-skill-usage/skill-usage"><img src="https://agentmods.dev/badge/skills/paultaki/claude-skill-usage/skill-usage.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00122 | $0.01163 |
| Opus 5 | $0.00061 | $0.00581 |
| Sonnet 5 | $0.00024 | $0.00233 |
| Haiku 4.5 | $0.00012 | $0.00116 |
Grade A, and why
skill-usage scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.
skill-usage
Answers: how often is each skill used, what does it cost, and should I keep / modernize / turn off / prune it?
How it works
The real record of skill use is the Skill tool_use events in ~/.claude/projects/**/*.jsonl. The bundled script parses those (no LLM) for usage + token cost + a heuristic baseline verdict. A Claude recommendation pass then adds judgment. Everything renders to one local HTML dashboard. Nothing is uploaded.
Two token costs (what "turn off" saves)
- Always-on tax — every enabled skill's name+description sits in context every session, paid even if never invoked. Scales with the number of enabled skills.
- On-invoke cost — when a skill fires, its full body loads once.
So the strongest turn-off candidates are skills you never use.
The script
The collector is bundled with this skill at scripts/skill-usage.py. Resolve its absolute path from this skill's directory:
- installed as a plugin:
"$CLAUDE_PLUGIN_ROOT/skills/skill-usage/scripts/skill-usage.py" - dropped into
~/.claude/skills/manually:~/.claude/skills/skill-usage/scripts/skill-usage.py
Outputs always go to ~/.claude/skill-usage/ (never next to the script), so they survive plugin updates.
Run it (usage only — fast, deterministic)
python3 "<script-path>" --open
Flags: --open open the dashboard · --prune print the never-used prune list · --rescan ignore cache · --demo build a sample-data dashboard (no transcripts; writes demo.html). First run parses all transcripts; later runs only re-parse new/changed files. Token counts use tiktoken if installed, else a chars/4 estimate (pip install tiktoken for a closer number).
This produces usage + token cost + a heuristic baseline verdict. For real recommendations, run the full pass below.
Full recommendation pass (Claude)
Hybrid engine: the script collects deterministic data; this pass adds judgment and writes the persistent verdict store.
- Run
python3 "<script-path>"— writes~/.claude/skill-usage/data/skill-usage.json+dashboard.html. - Fetch the current Anthropic skill-authoring docs (search if the URL moved; do not hardcode a stale link). Distill a best-practice checklist → write
~/.claude/skill-usage/data/best-practices.mdwith afetched: <date>line. - Read
~/.claude/skill-usage/data/skill-usage.json, the user's~/.claude/CLAUDE.md+~/.claude/rules/**, and each candidateSKILL.md(prioritize never-used + lint-flagged; confirm Keep+current in bulk). - Assign per skill
{verdict (keep|modernize|turn_off|prune), reason, modernize_note (modernize only), confidence}:- off-stack vs the user's stack → prune
- situational / maybe-later → turn_off
- valuable but behind docs (weak description, bloated body, stale refs) → modernize
- good + current → keep
- genuinely uncertain → keep / low-confidence (never a confident cut)
- Write
~/.claude/skill-usage/data/recommendations.json(schema inDESIGN.md§4.2). - Run
python3 "<script-path>" --open— re-renders, merging recommendations, and opens the dashboard.
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 59 lines · 122 tokens per session scan A 16978c3ccd28
skill-usage is a skill published in the GitHub repository paultaki/claude-skill-usage (2 stars, last pushed 2mo ago), licensed MIT. It adds 122 tokens to every session and 1,163 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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