# QA

> Pre-ship audit checklist for Ethereum dApps built with Scaffold-ETH 2. Give this to a separate reviewer agent (or fresh context) AFTER the build is complete. Covers only the bugs AI agents actually ship — validated by baseline testing against stock LLMs.

- Skill: `involvex/qa` (Agent Skill)
- Install (CLI): `npx skillmds@latest add involvex/qa`
- Raw SKILL.md: https://api.skillmd.com/api/skills/involvex/qa/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: involvex (https://skillmd.com/u/involvex)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/involvex/qa

---


# dApp QA — Pre-Ship Audit

This skill is for **review, not building.** Give it to a fresh agent after the dApp is built. The reviewer should:

1. Read the source code (`app/`, `components/`, `contracts/`)
2. Open the app in a browser and click through every flow
3. Check every item below — report PASS/FAIL, don't fix

---

## 🚨 Critical: Wallet Flow — Button Not Text

Open the app with NO wallet connected.

- ❌ **FAIL:** Text saying "Connect your wallet to play" / "Please connect to continue" / any paragraph telling the user to connect
- ✅ **PASS:** A big, obvious Connect Wallet **button** is the primary UI element

**This is the most common AI agent mistake.** Every stock LLM writes a `<p>Please connect your wallet</p>` instead of rendering `<RainbowKitCustomConnectButton />`.

---

## 🚨 Critical: Four-State Button Flow

The app must show exactly ONE primary button at a time, progressing through:

```
1. Not connected  → Connect Wallet button
2. Wrong network  → Switch to [Chain] button
3. Needs approval → Approve button
4. Ready          → Action button (Stake/Deposit/Swap)
```

Check specifically:

- ❌ **FAIL:** Approve and Action buttons both visible simultaneously
- ❌ **FAIL:** No network check — app tries to work on wrong chain and fails silently
- ❌ **FAIL:** User can click Approve, sign in wallet, come back, and click Approve again while tx is pending
- ✅ **PASS:** One button at a time. Approve button shows spinner, stays disabled until block confirms onchain. Then switches to the action button.

**In the code:** the button's `disabled` prop must be tied to `isPending` from `useScaffoldWriteContract`. Verify it uses `useScaffoldWriteContract` (waits for block confirmation), NOT raw wagmi `useWriteContract` (resolves on wallet signature):

```
grep -rn "useWriteContract" packages/nextjs/
```

Any match outside scaffold-eth internals → bug.

**Watch out: the post-submit allowance refresh gap.** When `writeContractAsync` resolves, it returns the tx hash — but wagmi hasn't re-fetched the allowance yet. During this window `isMining` is false AND `needsApproval` is still true (stale cache) — so the Approve button reappears clickable. The fix: after the tx submits, hold the button disabled with a cooldown while the allowance re-fetches:

```tsx
const [approveCooldown, setApproveCooldown] = useState(false);

const handleApprove = async () => {
  await approveWrite({ functionName: 'approve', args: [spender, amount] });
  // Hold disabled while allowance re-fetches
  setApproveCooldown(true);
  setTimeout(() => setApproveCooldown(false), 4000);
};

// Button:
<button disabled={isMining || approveCooldown}>
  {isMining || approveCooldown ? (
    <>
      <span className="loading loading-spinner loading-sm" /> Approving...
    </>
  ) : (
    'Approve'
  )}
</button>;
```

Cooldown timing: 4s works for most L2s (Base, Arb, Op). Mainnet may need 6-8s. Adjust based on network.

- ❌ **FAIL:** Approve button becomes clickable again for a few seconds after the tx submits
- ✅ **PASS:** Button stays locked through submission + cooldown, then switches to the action button

---

## 🚨 Critical: SE2 Branding Removal

AI agents treat the scaffold as sacred and leave all default branding in place.

- [ ] **Footer:** Remove BuidlGuidl links, "Built with 🏗️ SE2", "Fork me" link, support links. Replace with project's own repo link or clean it out
- [ ] **Tab title:** Must be the app name, NOT "Scaffold-ETH 2" or "SE-2 App" or "App Name | Scaffold-ETH 2"
- [ ] **README:** Must describe THIS project. Not the SE2 template README. Remove "Built with Scaffold-ETH 2" sections and SE2 doc links
- [ ] **Favicon:** Must not be the SE2 default

---

## Important: Contract Address Display

- ❌ **FAIL:** The deployed contract address appears nowhere on the page
- ✅ **PASS:** Contract address displayed using `<Address/>` component (blockie, ENS, copy, explorer link)

Agents display the connected wallet address but forget to show the contract the user is interacting with.

---

## Important: Address Input — Always `<AddressInput/>`

**EVERY input that accepts an Ethereum address must use `<AddressInput/>`, not a plain `<input type="text">`.**

- ❌ **FAIL:** `<input type="text" placeholder="0x..." value={addr} onChange={e => setAddr(e.target.value)} />`
- ✅ **PASS:** `<AddressInput value={addr} onChange={setAddr} placeholder="0x... or ENS name" />`

`<AddressInput/>` gives you ENS resolution (type "vitalik.eth" → resolves to address), blockie avatar preview, validation, and paste handling. A raw text input is unacceptable for address collection.

**In SE2, it's in `@scaffold-ui/components`:**

```typescript
import { AddressInput } from '@scaffold-ui/components';
// or
import { AddressInput } from '~~/components/scaffold-eth'; // if re-exported
```

**Quick check:**

```bash
grep -rn 'type="text"' packages/nextjs/app/ | grep -i "addr\|owner\|recip\|0x"
grep -rn 'placeholder="0x' packages/nextjs/app/
```

Any match → **FAIL**. Replace with `<AddressInput/>`.

The pair: `<Address/>` for **display**, `<AddressInput/>` for **input**. Always.

---

## Important: USD Values

- ❌ **FAIL:** Token amounts shown as "1,000 TOKEN" or "0.5 ETH" with no dollar value
- ✅ **PASS:** "0.5 ETH (~$1,250)" with USD conversion

Agents never add USD values unprompted. Check every place a token or ETH amount is displayed, including inputs.

---

## Important: OG Image Must Be Absolute URL

- ❌ **FAIL:** `images: ["/thumbnail.jpg"]` — relative path, breaks unfurling everywhere
- ✅ **PASS:** `images: ["https://yourdomain.com/thumbnail.jpg"]` — absolute production URL

Quick check:

```
grep -n "og:image\|images:" packages/nextjs/app/layout.tsx
```

---

## Important: RPC & Polling Config

Open `packages/nextjs/scaffold.config.ts`:

- ❌ **FAIL:** `pollingInterval: 30000` (default — makes the UI feel broken, 30 second update lag)
- ✅ **PASS:** `pollingInterval: 3000`
- ❌ **FAIL:** Using default Alchemy API key that ships with SE2
- ❌ **FAIL:** Code references `process.env.NEXT_PUBLIC_*` but the variable isn't actually set in the deployment environment (Vercel/hosting). Falls back to public RPC like `mainnet.base.org` which is rate-limited
- ✅ **PASS:** `rpcOverrides` uses `process.env.NEXT_PUBLIC_*` variables AND the env var is confirmed set on the hosting platform

**Verify the env var is set, not just referenced.** AI agents will change the code to use `process.env`, see the pattern matches PASS, and move on — without ever setting the actual variable on Vercel/hosting. Check:

```bash
vercel env ls | grep RPC
```

---

## Important: Dark Mode — No Hardcoded Dark Backgrounds

AI agents love the aesthetic of a dark UI and will hardcode it directly on the page wrapper:

```tsx
// ❌ FAIL — hardcoded black background, ignores system preference AND DaisyUI theme
<div className="min-h-screen bg-[#0a0a0a] text-white">
```

This bypasses the entire DaisyUI theme system. Light-mode users get a black page. The `SwitchTheme` toggle in the SE2 header stops working. `prefers-color-scheme` is ignored.

**Check for this pattern:**

```bash
grep -rn 'bg-\[#0\|bg-black\|bg-gray-9\|bg-zinc-9\|bg-neutral-9\|bg-slate-9' packages/nextjs/app/
```

Any match on a root layout div or page wrapper → **FAIL**.

- ❌ **FAIL:** Root page wrapper uses a hardcoded hex color or Tailwind dark bg class (`bg-[#0a0a0a]`, `bg-black`, `bg-zinc-900`, etc.)
- ❌ **FAIL:** `SwitchTheme` toggle is present in the header but the page ignores `data-theme` entirely
- ✅ **PASS:** All backgrounds use DaisyUI semantic variables — `bg-base-100`, `bg-base-200`, `text-base-content`
- ✅ **PASS (dark-only exception):** Theme is explicitly forced via `data-theme="dark"` on `<html>` **AND** the `<SwitchTheme/>` component is removed from the header

**The fix:**

```tsx
// ✅ CORRECT — responds to light/dark toggle and prefers-color-scheme
<div className="min-h-screen bg-base-200 text-base-content">
```

---

## Important: Phantom Wallet in RainbowKit

Phantom is NOT in the SE2 default wallet list. A lot of users have Phantom — if it's missing, they can't connect.

- ❌ **FAIL:** Phantom wallet not in the RainbowKit wallet list
- ✅ **PASS:** `phantomWallet` is in `wagmiConnectors.tsx`

---

## Important: Mobile Deep Linking

**RainbowKit v2 / WalletConnect v2 does NOT auto-deep-link to the wallet app.** It relies on push notifications instead, which are slow and unreliable. You must implement deep linking yourself.

On mobile, when a user taps a button that needs a signature, it must open their wallet app. Test this: open the app on a phone, connect a wallet via WalletConnect, tap an action button — does the wallet app open with the transaction ready to sign?

- ❌ **FAIL:** Nothing happens, user has to manually switch to their wallet app
- ❌ **FAIL:** Deep link fires BEFORE the transaction — user arrives at wallet with nothing to sign
- ❌ **FAIL:** `window.location.href = "rainbow://"` called before `writeContractAsync()` — navigates away and the TX never fires
- ❌ **FAIL:** It opens the wrong wallet (e.g. opens MetaMask when user connected with Rainbow)
- ❌ **FAIL:** Deep links inside a wallet's in-app browser (unnecessary — you're already in the wallet)
- ✅ **PASS:** Every transaction button fires the TX first, then deep links to the correct wallet app after a delay

### How to implement it

**Pattern: `writeAndOpen` helper.** Fire the write call first (sends the TX request over WalletConnect), then deep link after a delay to switch the user to their wallet:

```typescript
const writeAndOpen = useCallback(
  <T,>(writeFn: () => Promise<T>): Promise<T> => {
    const promise = writeFn(); // Fire TX — does gas estimation + WC relay
    setTimeout(openWallet, 2000); // Switch to wallet AFTER request is relayed
    return promise;
  },
  [openWallet],
);

// Usage — wraps every write call:
await writeAndOpen(() => gameWrite({ functionName: "click", args: [...] }));
```

**Why 2 seconds?** `writeContractAsync` must estimate gas, encode calldata, and relay the signing request through WalletConnect's servers. 300ms is too fast — the wallet won't have received the request yet.

**Detecting the wallet:** `connector.id` from wagmi says `"walletConnect"`, NOT `"rainbow"` or `"metamask"`. You must check multiple sources:

```typescript
const openWallet = useCallback(() => {
  if (typeof window === 'undefined') return;
  const isMobile = /iPhone|iPad|iPod|Android/i.test(navigator.userAgent);
  if (!isMobile || window.ethereum) return; // Skip if desktop or in-app browser

  // Check connector, wagmi storage, AND WalletConnect session data
  const allIds = [connector?.id, connector?.name, localStorage.getItem('wagmi.recentConnectorId')]
    .filter(Boolean)
    .join(' ')
    .toLowerCase();

  let wcWallet = '';
  try {
    const wcKey = Object.keys(localStorage).find((k) => k.startsWith('wc@2:client'));
    if (wcKey) wcWallet = (localStorage.getItem(wcKey) || '').toLowerCase();
  } catch {}
  const search = `${allIds} ${wcWallet}`;

  const schemes: [string[], string][] = [
    [['rainbow'], 'rainbow://'],
    [['metamask'], 'metamask://'],
    [['coinbase', 'cbwallet'], 'cbwallet://'],
    [['trust'], 'trust://'],
    [['phantom'], 'phantom://'],
  ];

  for (const [keywords, scheme] of schemes) {
    if (keywords.some((k) => search.includes(k))) {
      window.location.href = scheme;
      return;
    }
  }
}, [connector]);
```

**Key rules:**

1. **Fire TX first, deep link second.** Never `window.location.href` before the write call
2. **Skip deep link if `window.ethereum` exists** — means you're already in the wallet's in-app browser
3. **Check WalletConnect session data** in localStorage — `connector.id` alone won't tell you which wallet
4. **Use simple scheme URLs** like `rainbow://` — not `rainbow://dapp/...` which reloads the page
5. **Wrap EVERY write call** — approve, action, claim, batch — not just the main one

---

## 🚨 Critical: Contract Verification on Block Explorer

After deploying, every contract MUST be verified on the block explorer. Unverified contracts are a trust red flag — users can't read the source code, and it looks like you're hiding something.

- ❌ **FAIL:** Block explorer shows "Contract source code not verified" for any deployed contract
- ✅ **PASS:** All deployed contracts show verified source code with a green checkmark on the block explorer

**How to check:** Take each contract address from `deployedContracts.ts`, open it on the block explorer (Etherscan, Basescan, Arbiscan, etc.), and look for the "Contract" tab with a ✅ checkmark. If it shows bytecode only — not verified.

**How to fix (SE2):**

```bash
yarn verify --network mainnet   # or base, arbitrum, optimism, etc.
```

**How to fix (Foundry):**

```bash
forge verify-contract <ADDRESS> <CONTRACT> --chain <CHAIN_ID> --etherscan-api-key $ETHERSCAN_API_KEY
```

AI agents frequently skip verification because `yarn deploy` succeeds and they move on. Deployment is not done until verification passes.

---

## Important: Button Loading State — DaisyUI `loading` Class Is Wrong

AI agents almost always implement button loading states incorrectly when using DaisyUI + SE2.

**The mistake:** Adding `loading` as a class directly on a `btn`:

```tsx
// ❌ FAIL — DaisyUI's `loading` class on a `btn` replaces the entire button content
// with a spinner that fills the full button. No text, misaligned, looks broken.
<button className={`btn btn-primary ${isPending ? 'loading' : ''}`}>
  {isPending ? 'Approving...' : 'Approve'}
</button>
```

**The fix:** Remove `loading` from the button class, add an inline `loading-spinner` span inside the button alongside the text:

```tsx
// ✅ PASS — small spinner inside the button, text visible next to it
<button className="btn btn-primary" disabled={isPending}>
  {isPending && <span className="loading loading-spinner loading-sm mr-2" />}
  {isPending ? 'Approving...' : 'Approve'}
</button>
```

**Check for this in code:**

```bash
grep -rn '"loading"' packages/nextjs/app/
```

Any `"loading"` string in a button's className → **FAIL**.

- ❌ **FAIL:** `className={... isPending ? "loading" : ""}` on a button
- ✅ **PASS:** `<span className="loading loading-spinner loading-sm" />` inside the button

---

## Audit Summary

Report each as PASS or FAIL:

### Ship-Blocking

- [ ] Wallet connection shows a BUTTON, not text
- [ ] Wrong network shows a Switch button
- [ ] One button at a time (Connect → Network → Approve → Action)
- [ ] Approve button disabled with spinner through block confirmation
- [ ] Contracts verified on block explorer (Etherscan/Basescan/Arbiscan) — source code readable by anyone
- [ ] SE2 footer branding removed
- [ ] SE2 tab title removed
- [ ] SE2 README replaced

### Should Fix

- [ ] Contract address displayed with `<Address/>`
- [ ] Every address input uses `<AddressInput/>` — no raw `<input type="text">` for addresses
- [ ] USD values next to all token/ETH amounts
- [ ] OG image is absolute production URL
- [ ] pollingInterval is 3000
- [ ] RPC overrides set (not default SE2 key) AND env var confirmed set on hosting platform
- [ ] Favicon updated from SE2 default
- [ ] `--radius-field` in `globals.css` changed from `9999rem` to `0.5rem` (or similar) — no pill-shaped textareas
- [ ] Every contract error mapped to a human-readable message — no silent catch blocks, no raw hex selectors
- [ ] No hardcoded dark backgrounds — page wrapper uses `bg-base-200 text-base-content` (or `data-theme="dark"` forced + `<SwitchTheme/>` removed)
- [ ] Button loaders use inline `<span className="loading loading-spinner loading-sm" />` — NOT `className="... loading"` on the button itself
- [ ] Phantom wallet in RainbowKit wallet list
- [ ] Mobile: ALL transaction buttons deep link to wallet (fire TX first, then `setTimeout(openWallet, 2000)`)
- [ ] Mobile: wallet detection checks WC session data, not just `connector.id`
- [ ] Mobile: no deep link when `window.ethereum` exists (in-app browser)