WAVE: Skill for Claude Code

.agents/skills/expo-api-routes/SKILL.md

expo-api-routes is a skill for Claude Code, Codex from emilyLi2020/WAVE. It costs 18 tokens per session (2,108 once invoked), scanned B, a copy of expo-api-routes, Apache-2.0.

A set of guidelines for creating server-side API endpoints in Expo Router. Expo Router is a navigation and application framework for Expo apps.

In plain words
What is it for?
Adding endpoints for protected API calls, database work, webhooks, server-side validation, rate limits, and heavy computation.
Why use it?
It helps keep secrets and database operations off the mobile client, where users could access them.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is emilyLi2020/WAVE's own configuration. It tells Claude Code and Codex how to work on WAVE itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything WAVE configures →

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is import { requireAuth } from "../../utils/auth";.

Reuse

Borrowing it

Nothing to install: this file belongs to emilyLi2020/WAVE. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/emilyLi2020/WAVE/main/.agents/skills/expo-api-routes/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/emilyLi2020/WAVE

Made for: Claude Code, Codex.

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 expo-api-routes

README.md
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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 expo-api-routes

Your own site · 80×15
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Per session 18 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,108 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod 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 $0.00018 $0.02108
Opus 5 $0.00009 $0.01054
Sonnet 5 $0.00004 $0.00422
Haiku 4.5 $0.00002 $0.00211

Measured 9d ago against content hash db4d2cd6fbce, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade B, and why

expo-api-routes scanned grade B with 2 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 9d 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.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

const response = await fetch("https://api.openai.com/v1/chat/completions", { method: "POST",

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

Test with curl:
Origin

This is a copy

100% identical to expo-api-routes — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/expo-api-routes/SKILL.md · 369 lines

How it starts

The opening of the file, as written. The whole thing — 369 lines — stays where its author put it; the contents beside it link to each section on GitHub.

When to Use API Routes

Use API routes when you need:

  • Server-side secrets — API keys, database credentials, or tokens that must never reach the client
  • Database operations — Direct database queries that shouldn't be exposed
  • Third-party API proxies — Hide API keys when calling external services (OpenAI, Stripe, etc.)
  • Server-side validation — Validate data before database writes
  • Webhook endpoints — Receive callbacks from services like Stripe or GitHub
  • Rate limiting — Control access at the server level
  • Heavy computation — Offload processing that would be slow on mobile

When NOT to Use API Routes

Avoid API routes when:

  • Data is already public — Use direct fetch to public APIs instead
  • No secrets required — Static data or client-safe operations
  • Real-time updates needed — Use WebSockets or services like Supabase Realtime
  • Simple CRUD — Consider Firebase, Supabase, or Convex for managed backends
  • File uploads — Use direct-to-storage uploads (S3 presigned URLs, Cloudflare R2)
  • Authentication only — Use Clerk, Auth0, or Firebase Auth instead

File Structure

API routes live in the app directory with +api.ts suffix:

app/
  api/
    hello+api.ts          → GET /api/hello
    users+api.ts          → /api/users
    users/[id]+api.ts     → /api/users/:id
  (tabs)/
    index.tsx

Basic API Route

// app/api/hello+api.ts
export function GET(request: Request) {
  return Response.json({ message: "Hello from Expo!" });
}

HTTP Methods

Export named functions for each HTTP method:

// app/api/items+api.ts
export function GET(request: Request) {
  return Response.json({ items: [] });
}

export async function POST(request: Request) {
  const body = await request.json();
  return Response.json({ created: body }, { status: 201 });
}

export async function PUT(request: Request) {
  const body = await request.json();
  return Response.json({ updated: body });
}

export async function DELETE(request: Request) {
  return new Response(null, { status: 204 });
}

Read the full file on GitHub · 369 lines

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. 9d ago First seen · 369 lines · 18 tokens per session scan B db4d2cd6fbce

Subscribe to this mod's changes

expo-api-routes is a skill published in the GitHub repository emilyLi2020/WAVE (2 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 18 tokens to every session and 2,108 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B with 2 findings (sends data to an external url, makes network calls). It is 100% identical to expo-api-routes, differing in 0 lines, and is treated as a copy.

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