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 skills add Jamie-BitFlight/claude_skills --skill review-performance-changegit clone --depth 1 https://github.com/Jamie-BitFlight/claude_skillsWrote 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/jamie-bitflight/claude_skills/review-performance-change)<a href="https://agentmods.dev/skills/jamie-bitflight/claude_skills/review-performance-change"><img src="https://agentmods.dev/badge/skills/jamie-bitflight/claude_skills/review-performance-change/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/jamie-bitflight/claude_skills/review-performance-change"><img src="https://agentmods.dev/badge/skills/jamie-bitflight/claude_skills/review-performance-change.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00030 | $0.00192 |
| Opus 5.5 | $0.00012 | $0.00077 |
| Sonnet 5.5 | $0.00006 | $0.00038 |
| Haiku 4.5 | $0.00003 | $0.00019 |
Grade A, and why
review-performance-change 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 7d 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.
What it actually says
Review Performance Change
Load /dh:review-principles and read Review methods before
assessing the supplied scope. Preserve the caller's applicability and result contract.
Review only the supplied change scope. Identify changed hot paths, I/O boundaries, queries, allocation/collection growth, concurrency, caching, and algorithmic work. Look for N+1 operations, blocking work on async paths, repeated expensive work, unbounded growth, and changed complexity where consequence is material. Do not reject on stylistic micro-optimization. Return APPROVE, REJECT, or SKIP when the change has no plausible performance-relevant execution path. Support blockers with a concrete path and evidence; request measurement when static inspection cannot establish impact.
What ships with it
1 file 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.
- 7d ago Changed · -1 lines 783dcd467304
- 15d ago Changed · +4 lines 0a615bef8762
- 28d ago First seen · 8 lines · 30 tokens per session scan A c7fa10ca6696
review-performance-change is a skill published in the GitHub repository Jamie-BitFlight/claude_skills (67 stars, last pushed 4d ago), licensed MIT. It adds 30 tokens to every session and 192 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-26.
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