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 rules/ivangrynenko/cursorrules/javascript-performancegit clone --depth 1 https://github.com/ivangrynenko/cursorrulesWhat 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 | $0.00000 | $0.00198 |
| Opus 5 | $0.00000 | $0.00099 |
| Sonnet 5 | $0.00000 | $0.00040 |
| Haiku 4.5 | $0.00000 | $0.00020 |
Grade A, and why
javascript-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 2d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- javascript-performance — 100% identical, 0 lines differ
What it actually says
JavaScript Performance Optimization
actions:
-
type: enforce conditions:
-
pattern: "\buseState\(([^)]*)\)" message: "Avoid unnecessary state updates."
-
pattern: "React\.memo\(" message: "Consider using React.memo() to optimize component re-renders."
-
pattern: "\b\(\)\s*=>\s*{" message: "Avoid using anonymous functions in render methods."
-
-
type: suggest message: | Performance tips:
- Use memoization for expensive calculations.
- Optimize FlatList with performance props.
- Minimize unnecessary re-renders.
metadata: priority: high version: 1.0
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.
- 2d ago First seen · 34 lines · 198 tokens per session scan A 2055c06cc248
javascript-performance is a cursor rule published in the GitHub repository ivangrynenko/cursorrules (87 stars, last pushed 10mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 198 tokens. 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 2026-08-30.
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