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/ericrisco/rsc-harness/react-nativenpx skills add ericrisco/rsc-harness --skill react-nativegit clone --depth 1 https://github.com/ericrisco/rsc-harnessWrote 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/skills/ericrisco/rsc-harness/react-native)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/react-native"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/react-native.svg" alt="Measured on agentmods" 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 | $0.00090 | $0.02953 |
| Opus 5 | $0.00045 | $0.01477 |
| Sonnet 5 | $0.00018 | $0.00591 |
| Haiku 4.5 | $0.00009 | $0.00295 |
Grade A, and why
react-native 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 today.
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 — 216 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Native (app code)
Hand-off — the app vs its motion. Animation and gestures in a React Native app — Reanimated
worklets on the UI runtime, gesture handoff, sheets, press feedback, haptics — are
../motion-craft/SKILL.md's, whose guidance is platform-agnostic and applies to bare React Native as well as Expo.
You write the code that runs inside the app: render, navigate, animate, list, persist, and author native modules. Mobile is split across two skills by verb — run the verb test before doing anything:
| Verb in the request | Skill |
|---|---|
| render / navigate / animate / list / persist / author-native-module / debug-runtime | react-native (here) |
build / submit / update (OTA) / prebuild / config-plugin / eas.json / channel / runtime-version |
../expo/SKILL.md |
Assume the New Architecture is on (Fabric + Turbo Modules). It is mandatory from RN 0.82 / Expo SDK 55 — RN 0.82 (2025-10-08) ignores any disable flag, and SDK 55 is New-Arch-only. SDK 54 (RN 0.81) was the last that could opt out. Never write newArchEnabled: false to dodge a bug; fix the bug. Why: the flag is a no-op on current versions, so the "fix" silently does nothing.
Reference SDK→RN map (accessed 2026-06-02): SDK 53 = RN 0.79, SDK 54 = RN 0.81 (React Compiler GA), SDK 55 = RN 0.83.
Project shape — pick a router first
This is the one real branch at scaffold time:
| Use | When |
|---|---|
| Expo Router (file-based) | New apps, web parity, deep links, typed routes. The recommended default. It is a layer on top of React Navigation; both are Expo-team maintained. |
| React Navigation v7 (static API) | Brownfield apps, native integration, highly bespoke custom transitions where you need imperative control. |
Default file tree for an Expo Router app:
app/ # routes — file system IS the navigation
(auth)/ # group: unauthenticated screens
(app)/ # group: authenticated screens
(tabs)/ # nested tab navigator
_layout.tsx # root layout + providers
components/ # dumb, reusable UI
features/<domain>/ # feature-scoped screens, hooks, components
lib/ # clients, query setup, storage, utils
What ships with it
5 files 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.
- today First seen · 216 lines · 90 tokens per session scan A b3c37d2efc1b
react-native is a skill published in the GitHub repository ericrisco/rsc-harness (60 stars, last pushed yesterday), licensed MIT. It adds 90 tokens to every session and 2,953 once invoked, about $0.0005 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 2026-09-03.
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