build-and-test

build-and-test is a skill for Claude Code, Codex from Lykhoyda/rn-dev-agent. It costs 37 tokens per session (251 once invoked), scanned A, original, MIT.

A guided workflow for building and testing Expo or React Native apps. It builds the app locally or with EAS, installs it, starts Metro, and tests a requested feature from start to finish.

In plain words
What is it for?
Use it to build an app, install it on a device, start Metro, and verify a feature through a complete user flow.
Why use it?
It brings the build, installation, development server, and end-to-end testing steps into one documented process.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present. Also seen: mentions Codex; $skill-name invocation.

Part of the rn-dev-agent plugin — 28 skills, 17 commands, 6 agents, 6 hooks shipped together

Good fit Use it to build an app, install it on a device, start Metro, and verify a feature through a complete user flow.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/lykhoyda/rn-dev-agent/build-and-test
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.

Any agent
npx skills add Lykhoyda/rn-dev-agent --skill build-and-test
Clone the repo
git clone --depth 1 https://github.com/Lykhoyda/rn-dev-agent

Made for: Claude Code, Codex.

Or install rn-dev-agent, the plugin that ships this one along with the rest of its 28 skills, 17 commands, 6 agents, 6 hooks.

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.

agentmods badge for build-and-test

README.md
[![agentmods](https://agentmods.dev/badge/skills/lykhoyda/rn-dev-agent/build-and-test/github.svg)](https://agentmods.dev/skills/lykhoyda/rn-dev-agent/build-and-test)
Your own site
<a href="https://agentmods.dev/skills/lykhoyda/rn-dev-agent/build-and-test"><img src="https://agentmods.dev/badge/skills/lykhoyda/rn-dev-agent/build-and-test/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.

agentmods 80×15 button for build-and-test

Your own site · 80×15
<a href="https://agentmods.dev/skills/lykhoyda/rn-dev-agent/build-and-test"><img src="https://agentmods.dev/badge/skills/lykhoyda/rn-dev-agent/build-and-test.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 251 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00037 $0.00251
Opus 5.5 $0.00015 $0.00100
Sonnet 5.5 $0.00007 $0.00050
Haiku 4.5 $0.00004 $0.00025

Measured 1mo ago against content hash f33ba25e0f95, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

build-and-test 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.

Origin

Copies of this mod

8 near-identical copies found in the catalogue:

packages/claude-plugin/codex-skills/build-and-test/SKILL.md · 14 lines

What it actually says

build-and-test

Invoke this workflow explicitly as $rn-dev-agent:build-and-test [request text].

The exact text after the skill mention is the conceptual request. It is user-message data, not a shell variable or a Claude command-template substitution. Preserve it while applying the workflow's documented grammar; pass only separately parsed and validated values to MCP tools or package helpers. Never use eval or interpolate the raw request into a shell command.

Read the complete package-local workflow before acting. Resolve that file and every helper relative to this exact SKILL.md path; never scan Codex caches or rely on a plugin-root environment variable. If a required cdp MCP tool is absent from the active task, stop and use the read-only discovery diagnosis. Do not substitute raw Maestro for rn-dev-agent strict proof.

Files

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.

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.

  1. 1mo ago Changed f33ba25e0f95
  2. 1mo ago First seen · 14 lines · 37 tokens per session scan A fbec9acc6cb6

Subscribe to this mod's changes

build-and-test is a skill published in the GitHub repository Lykhoyda/rn-dev-agent (20 stars, last pushed yesterday), licensed MIT. It adds 37 tokens to every session and 251 once invoked, about $0.0001 per session on Opus 5.5. 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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