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/tyrchen/cursor-rust-rulesWrote 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/tyrchen/cursor-rust-rules/performance)<a href="https://agentmods.dev/rules/tyrchen/cursor-rust-rules/performance"><img src="https://agentmods.dev/badge/rules/tyrchen/cursor-rust-rules/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/tyrchen/cursor-rust-rules/performance"><img src="https://agentmods.dev/badge/rules/tyrchen/cursor-rust-rules/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 | $0.00000 | $0.04168 |
| Opus 5.5 | $0.00000 | $0.01667 |
| Sonnet 5.5 | $0.00000 | $0.00834 |
| Haiku 4.5 | $0.00000 | $0.00417 |
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 1mo 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 — 639 lines — stays where its author put it; the contents beside it link to each section on GitHub.
⚡ RUST PERFORMANCE OPTIMIZATION
TL;DR: Performance optimization strategies for Rust applications, focusing on zero-cost abstractions, memory management, and profiling-driven optimization.
🔍 PERFORMANCE OPTIMIZATION STRATEGY
graph TD
Start["Performance Issue"] --> Measure["Profile & Measure"]
Measure --> Bottleneck{"Bottleneck<br>Type?"}
Bottleneck -->|CPU| CPUOpt["CPU Optimization"]
Bottleneck -->|Memory| MemOpt["Memory Optimization"]
Bottleneck -->|I/O| IOOpt["I/O Optimization"]
Bottleneck -->|Concurrency| ConcOpt["Concurrency Optimization"]
CPUOpt --> SIMD["SIMD Vectorization"]
CPUOpt --> Algorithms["Algorithm Optimization"]
CPUOpt --> CompileTime["Compile-Time Optimization"]
MemOpt --> Allocation["Allocation Strategy"]
MemOpt --> DataStructure["Data Structure Choice"]
MemOpt --> Caching["Caching Patterns"]
IOOpt --> Buffering["Buffering Strategy"]
IOOpt --> AsyncIO["Async I/O Patterns"]
IOOpt --> Batching["Request Batching"]
ConcOpt --> Parallelism["Parallel Processing"]
ConcOpt --> Channels["Channel Optimization"]
ConcOpt --> LockFree["Lock-Free Structures"]
SIMD --> Verify["Benchmark & Verify"]
Algorithms --> Verify
CompileTime --> Verify
Allocation --> Verify
DataStructure --> Verify
Caching --> Verify
Buffering --> Verify
AsyncIO --> Verify
Batching --> Verify
Parallelism --> Verify
Channels --> Verify
LockFree --> Verify
style Start fill:#4da6ff,stroke:#0066cc,color:white
style Measure fill:#ffa64d,stroke:#cc7a30,color:white
style CPUOpt fill:#4dbb5f,stroke:#36873f,color:white
style MemOpt fill:#d94dbb,stroke:#a3378a,color:white
🎯 PERFORMANCE PRINCIPLES
Measure First, Optimize Second
// ✅ Always profile before optimizing
use std::time::Instant;
#[cfg(feature = "profiling")]
macro_rules! time_it {
($name:expr, $block:block) => {{
let start = Instant::now();
let result = $block;
let duration = start.elapsed();
tracing::info!("{} took {:?}", $name, duration);
result
}};
}
#[cfg(not(feature = "profiling"))]
macro_rules! time_it {
($name:expr, $block:block) => {
$block
};
}
// Usage
fn process_data(data: &[u8]) -> Vec<u8> {
time_it!("process_data", {
// Expensive computation here
data.iter().map(|&b| b.wrapping_mul(2)).collect()
})
}
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.
- 1mo ago First seen · 639 lines · 0 tokens per session scan A c7110a0c389b
performance is a cursor rule published in the GitHub repository tyrchen/cursor-rust-rules (27 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 4,168 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.
Other cursor rules, from other repositories
rust-module-refactor
Use when splitting Rust modules, moving tests, tightening visibility, or preserving facades during refactors.
rust-architect
PoolAI — Rust Architect workflow: runtime stack, MSYS2, target/ disk, pre-push checks, docs sync.
table-of-contents-standard
Standard section ordering and TOC format for Verus source files.
arc-deref-pattern
When implementing parallel (Mt) algorithms in Verus, do NOT assume.
wrap-vs-specify
When to use externaltypespecification vs wrapper struct for Verus specs.
core
Core STT/TTS abstraction layer documentation.