# 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. Use this skill whenever you are finalizing a dApp built with Scaffold-ETH 2.

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

---


# dApp QA — Pre-Ship Audit For Scaffold-ETH 2 Builds

## What You Probably Got Wrong

**"The app deployed, so we are done."** For SE2 builds, shipping includes UX correctness, metadata, RPC reliability, contract verification, and branding cleanup.

**"The flow is obvious."** If Connect, Network, Approve, and Action are not strictly one-at-a-time with proper pending states, users will make duplicate or failing transactions.

**"SE2 defaults are fine in production."** Default README/footer/title/favicon and default RPC fallbacks are template scaffolding, not production decisions.

**"Pass means no console errors."** QA pass/fail here is behavioral and user-facing: real wallet flow, mobile deep-link behavior, readable errors, and trust signals must be validated.

Give this 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

Fetch `crops/SKILL.md` first and include a CROPS Review in the report. Simple apps can get a concise baseline review; apps with funds, approvals, custody, wallet permissions, L2/bridge flows, private user data, identity, stablecoins, admin powers, or hosted RPC/indexer/relayer/paymaster/frontend infrastructure need the full four-pillar review.

---

## 🚨 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:** Main onchain CTA renders instead of a "Switch to [Chain]" button when the connected wallet is on the wrong network. SE-2's header `WrongNetworkDropdown` is **not sufficient** — the action button itself must become the switch CTA, or the user clicks Sign/Stake/Deposit on the wrong chain and eats a silent wagmi error.
- ❌ **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.
- ✅ **PASS:** Action button's render path branches on `useChainId() === targetNetwork.id` (or equivalent); mismatch renders a `useSwitchChain`-driven "Switch to [Chain]" button in the **same slot** as the primary CTA.

**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: two gaps, both allow double-approve.**

`isPending` from wagmi drops to `false` when the wallet returns the tx hash — not when the tx confirms. `writeContractAsync` is still awaiting confirmation. During that window `isPending = false` AND `approveCooldown = false` → button re-enables mid-flight.

Fix requires TWO states:
- `approvalSubmitting` — set at top of handler, cleared in `finally {}` (covers click→hash gap)
- `approveCooldown` — set after `await` resolves, cleared after 4s + refetch (covers confirm→cache gap)

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

const handleApprove = async () => {
  if (approvalSubmitting || approveCooldown) return;
  setApprovalSubmitting(true);
  try {
    await approveWrite({ functionName: "approve", args: [spender, amount] });
    setApproveCooldown(true);
    setTimeout(() => { setApproveCooldown(false); refetchAllowance(); }, 4000);
  } catch (e) {
    notifyError("Approval failed");
  } finally {
    setApprovalSubmitting(false); // must be finally — releases on rejection too
  }
};

<button disabled={isPending || approvalSubmitting || approveCooldown}>
```

- ❌ **FAIL:** Button `disabled` only reads `isPending` or only `approveCooldown`
- ❌ **FAIL:** No `approvalSubmitting` state, or it's not cleared in `finally {}`
- ✅ **PASS:** `disabled={isPending || approvalSubmitting || approveCooldown}` with both states managed correctly

---

## 🚨 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: CROPS Review for Trust Assumptions

- ❌ **FAIL:** No `CROPS Review` block in the QA report.
- ❌ **FAIL:** The CROPS Review lists generic values but does not name who can block users, what data leaks, who controls funds/upgrades/recovery, and how users exit.
- ❌ **FAIL:** The app has production-relevant trust assumptions (funds, approvals, custody, wallet permissions, L2/bridge, private data, identity, stablecoins, admin powers, hosted RPC/indexer/relayer/paymaster/frontend) but the CROPS Review is only a short gate and never uses `crops/SKILL.md` for the deep template.
- ✅ **PASS:** A concrete `CROPS Review` block is present, names the chosen default, accepted compromises, and the user's escape path. Depth matches the app's trust assumptions.

---

## 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
- ❌ **FAIL:** `services/web3/wagmiConfig.tsx` still includes bare `http()` fallback transport (silently hits public RPCs in parallel, causing rate limits)
- ✅ **PASS:** Bare `http()` fallback removed; only intended configured transports remain

**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: SE2 `externalContracts.ts` Registration

Scaffold hooks only work with contracts registered in `deployedContracts.ts` (auto-generated) or `externalContracts.ts` (manual). If external contracts are not registered, frontend reads/writes silently fail.

- ❌ **FAIL:** Frontend code references token/protocol contracts that are missing from `packages/nextjs/contracts/externalContracts.ts`
- ❌ **FAIL:** `deployedContracts.ts` manually edited to add external contracts
- ✅ **PASS:** All external contracts are defined in `externalContracts.ts` with correct chain, address, and ABI

Example:
```typescript
export default {
  8453: {
    USDC: {
      address: "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      abi: [...],
    },
  },
} as const;
```

Never edit `deployedContracts.ts` directly. It is regenerated on deploy.

---

## 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

---

## Important: SE2 Pill-Shaped Inputs (`--radius-field`)

SE2 DaisyUI theme defaults to `--radius-field: 9999rem`, which creates pill-shaped textareas/selects and often clips content.

- ❌ **FAIL:** `--radius-field: 9999rem` remains in `packages/nextjs/styles/globals.css`
- ✅ **PASS:** `--radius-field` is changed to `0.5rem` (or similar) in both light and dark theme blocks

Fix in theme (not per component):
```css
/* In BOTH @plugin "daisyui/theme" blocks */
--radius-field: 0.5rem;
```

Do not patch this by sprinkling `rounded-*` utility classes per input; fix it once at theme level.

---

## SE2 References

- Docs: https://docs.scaffoldeth.io/
- UI Components: https://ui.scaffoldeth.io/
- SpeedRun Ethereum: https://speedrunethereum.com/

---

## Audit Summary

Report each as PASS or FAIL:

### Ship-Blocking
- [ ] Wallet connection shows a BUTTON, not text
- [ ] Wrong network shows a Switch button **in the primary CTA slot** (not only in the header dropdown)
- [ ] One button at a time (Connect → Network → Approve → Action)
- [ ] Approve button locked through full cycle: `approvalSubmitting` (click→hash), `approveCooldown` (confirm→cache refresh) — both states required, both on the `disabled` prop
- [ ] Contracts verified on block explorer (Etherscan/Basescan/Arbiscan) — source code readable by anyone
- [ ] CROPS Review present in the QA report: names the chosen default, accepted compromises, who can block users, what data leaks, who controls funds/upgrades/recovery, and the user's escape path
- [ ] 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)