A set of rules for making software run more efficiently across databases, caching, web interfaces, asynchronous work, and bundled files.

Use it to review database access, caching, React interfaces, asynchronous calls, bundle size, and performance measurements before optimizing.

It points out common sources of slow performance, such as repeated database queries, unnecessary interface updates, and sequential independent operations.

performance — Cursor rule for Cursor by dasomel/oh-my-cursor

Install

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.

Clone the repo

git clone --depth 1 https://github.com/dasomel/oh-my-cursor

Made for: Cursor.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/rules/dasomel/oh-my-cursor/performance/github.svg)](https://agentmods.dev/rules/dasomel/oh-my-cursor/performance)

Your own site

<a href="https://agentmods.dev/rules/dasomel/oh-my-cursor/performance"><img src="https://agentmods.dev/badge/rules/dasomel/oh-my-cursor/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.

Your own site · 80×15

<a href="https://agentmods.dev/rules/dasomel/oh-my-cursor/performance"><img src="https://agentmods.dev/badge/rules/dasomel/oh-my-cursor/performance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 0 Nothing until a file matches its globs; then the whole rule loads.

When invoked 294 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00000	$0.00294
Opus 5.5	$0.00000	$0.00118
Sonnet 5.5	$0.00000	$0.00059
Haiku 4.5	$0.00000	$0.00029

Measured 2mo ago against content hash 83658f8487ab, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

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.

rules/practices/performance.mdc · 42 lines

What it actually says

Performance Standards

Database

N+1 queries: Always batch-load related records
Use database-level pagination (LIMIT/OFFSET or cursor-based)
Index foreign keys and frequently-queried columns
Avoid SELECT * — specify needed columns

Caching

Cache expensive computations (memoization for pure functions)
Cache HTTP responses where appropriate (ETags, Cache-Control)
Invalidate cache on data mutation
Don't cache sensitive or user-specific data globally

Frontend (React/UI)

Avoid unnecessary re-renders (useMemo, useCallback for stable references)
Lazy-load routes and heavy components
Virtualize long lists (>100 items)
Avoid inline object/function creation in JSX

Async Operations

Run independent async operations in parallel: await Promise.all([...])
Don't await inside loops for independent operations
Set timeouts on external calls
Handle backpressure in streams

Bundle Size

Check bundle size impact before adding dependencies
Tree-shake unused code
Use dynamic imports for large libraries used infrequently

Measurement

Measure before optimizing (don't guess)
Profile in production conditions (not dev mode)
Set performance budgets and enforce in CI

Changes

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 · 0 tokens per session scan A 83658f8487ab

Subscribe to this mod's changes

performance is a cursor rule published in the GitHub repository dasomel/oh-my-cursor (3 stars, last pushed 7mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 294 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 2026-08-31.

Debugging

error-handling-and-validation

A code-quality guide for handling errors, invalid inputs, edge cases, preconditions, logging, and user-friendly error messages.

holtwood/awesome-cursorrules-zh · 185 tokens

css-render-blocking-diagnosis

Cursor rule "css-render-blocking-diagnosis" from adobecom/da-express-milo, covering css render-blocking diagnosis & resolution, critical learning from 98 pagespeed achievement, primary diagnostic protocol, step 1: css blocking symptom recognition and step 2: css loading sequence audit.

adobecom/da-express-milo · 1,102 tokens

performance