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 skills/legendapp/legend-skills/react-coding-stylenpx skills add LegendApp/legend-skills --skill react-coding-stylegit clone --depth 1 https://github.com/LegendApp/legend-skillsWhat 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 | $0.00078 | $0.01829 |
| Opus 5 | $0.00039 | $0.00915 |
| Sonnet 5 | $0.00016 | $0.00366 |
| Haiku 4.5 | $0.00008 | $0.00183 |
Grade A, and why
react-coding-style 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 3d 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 — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Coding Style
Optimize for the smallest render surface. Keep volatile reads in leaves, prevent changing identities from propagating through stable subtrees, and accept modest structural complexity when it avoids broad or expensive re-renders. Preserve correctness: event or imperative freshness is not a substitute for props or subscriptions that update rendered output.
Scope
- Follow the requested mode: implement safe improvements within scope, or report findings without editing during a review or audit. Suggest changes that substantially broaden state ownership, component architecture, dependencies, or public APIs unless the user approves that wider work.
- During explicit performance work, investigate every evidence-backed source of material render cost. During ordinary React work, apply relevant safeguards within scope and mention broader opportunities only when they are likely material.
First Pass
- Check the React version, platform, lint rules, and nearby component patterns. Determine whether React Compiler is enabled for the target build and whether it compiles the affected components or hooks; do not infer coverage from package presence or a single config flag.
- Identify which values render UI and which are read only by events, async work, subscriptions, or imperative bridges.
- Trace each changing value through props, context, callbacks, and subscriptions; identify how much of the tree and which expensive or native boundaries it can update.
- Find the smallest component or selector that needs each changing value.
- Locate existing selector, stable-callback, latest-ref, memo, observer, and external-store helpers.
Render Path
- Keep render execution limited to deriving UI. Hoist static construction and run interaction, async, or imperative work at the boundary that triggers it.
- Keep event or imperative reads behind stable callbacks or refs, and isolate external synchronization in effects or focused hooks. Do not move reactive reads that must update UI into non-reactive paths.
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.
- 3d ago First seen · 96 lines · 78 tokens per session scan A 3d831586b5ab
react-coding-style is a skill published in the GitHub repository LegendApp/legend-skills (36 stars, last pushed 1mo ago), licensed MIT. It adds 78 tokens to every session and 1,829 once invoked, about $0.0004 per session on Opus 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 2026-08-30.
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