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.
git clone --depth 1 https://github.com/mhmdreza-rafiei/agent-toolsWrote 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/rules/mhmdreza-rafiei/agent-tools/performance)<a href="https://agentmods.dev/rules/mhmdreza-rafiei/agent-tools/performance"><img src="https://agentmods.dev/badge/rules/mhmdreza-rafiei/agent-tools/performance/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/rules/mhmdreza-rafiei/agent-tools/performance"><img src="https://agentmods.dev/badge/rules/mhmdreza-rafiei/agent-tools/performance.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 | $0.00017 | $0.00355 |
| Opus 5.5 | $0.00007 | $0.00142 |
| Sonnet 5.5 | $0.00003 | $0.00071 |
| Haiku 4.5 | $0.00002 | $0.00036 |
Grade A, and why
performance 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 2mo 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
Performance
Applies when performance is a stated requirement or the change touches a hot path. Load for user-facing features, data pipelines, hot loops. Not every chat — premature optimization is a real cost.
Budget before optimization
- A performance change needs a budget: LCP / TBT / CLS for web, p95 / p99 latency for APIs, throughput for pipelines. No budget → no target → no way to know when to stop.
- If the user gave no budget, ask once. If they don't know, propose a sane default and label it as a suggestion.
Measure, then fix
- Measure before optimizing. A guess about where time goes is usually wrong.
- Fix the measured bottleneck, then re-measure. One bottleneck at a time.
- The cheapest fix is usually algorithmic (a better data structure, fewer passes, an index), not a micro-optimization.
Hot paths
- N+1 queries, repeated parsing, re-reading the same file, synchronous I/O in a loop — these are the usual suspects. Check them first.
- Cache only what is expensive and stable. A cache invalidation bug is worse than no cache.
Do not
- Optimize without a budget and a measurement.
- Trade correctness for speed without flagging it (a
ponytail:comment naming the ceiling is fine). - Add a dependency for a perf gain the stdlib already covers.
- Micro-optimize a path that isn't hot.
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.
- 2mo ago First seen · 42 lines · 17 tokens per session scan A b0ade8c5dad9
performance is a cursor rule published in the GitHub repository mhmdreza-rafiei/agent-tools (5 stars, last pushed 18d ago), licensed MIT. It adds 17 tokens to every session and 355 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 2026-08-31.
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