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including the odd cases real users run into.

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DappDrillHarbor Labs/Harbor Vault

TestsRunsSettings

Harbor Vault

harborvault.xyz

Last run 2 min ago

Add testExplore againRun all

3 conditions failed

4 bugs from 41 checks

Last 14 days93% of 14 runs passed

PassedFailed4 min typical run

Tests6Checks41Bugs4

AllPassed 6By condition

Deposit hUSDC into the vaultPassed · 2 min ago

Rejected in walletFailed

Slow RPC

Wrong networkFailed

Switched account

Not enough gas

Withdraw hUSDCPassed · 2 min ago

Rejected in wallet

Slow RPC

Not enough gasFailed

Withdraw half of the depositPassed · 2 min ago

Claim the deposit bonusPassed · 2 min ago

Get test hUSDCPassed · 2 min ago

Connect a walletPassed · 2 min ago

How it works

Finds the flows that move money and writes a test for each: a goal, an expected result, short steps.
DappDrillHarbor Labs/Harbor Vault
TestsRunsSettings
H
Harbor Vault
harborvault.xyzLast run 2 min ago
Add testExplore againRun all
harborvault.xyz
Harbor Vault
VaultRewardsActivity
0x7a3F…41e1
DepositWithdraw
Amount
250hUSDC
Balance 1,000 hUSDCGet test hUSDC
Deposit
You receive about 242.43 hvUSDC
12.50 hUSDC to claim5% bonus on every deposit
Claim rewards
hUSDC VaultDeposit hUSDC and earn yield. Withdraw any time.
TVL102,418
APY4.8%
Share price1.0312
Your position0.00 hvUSDCworth 0.00 hUSDC
Withdrawing with too little ETH for gas
Exploring · 3:12 · 6 minutes leftStop
Running tests and checks
Tests5User flows, run again on every change
Checks23One-off checks while exploring
Bugs2What either one finds wrong
Deposit stays on “Confirming…” after rejecting in the wallet
Saved a test: Claim the deposit bonus
Wallet asked to deposit 250 hUSDC
Withdraw 100 hUSDC worked
Looking at the Rewards page
On the wrong network the deposit was sent anyway
Trying the faucet twice in a row
Withdraw hUSDC
Deposit hUSDC
Claim the bonus
Get test hUSDC
Switch account
Write your own tests or edit the ones it wrote. Say what should happen in plain words, and an LLM checks it on every run, not just a fixed script.
DappDrillHarbor Labs/Harbor Vault
TestsRunsSettings
H
Harbor Vault
harborvault.xyzLast run 2 min ago
Add testExplore againRun all
Tests6Checks41Bugs4
AllPassed 6By condition
Deposit hUSDC into the vaultPassed · 2 min ago
Rejected in walletFailed
Slow RPC
Wrong networkFailed
Switched account
Not enough gas
Withdraw hUSDCPassed · 2 min ago
Rejected in wallet
Slow RPC
Not enough gasFailed
Withdraw half of the depositPassed · 2 min ago
Claim the deposit bonusPassed · 2 min ago
Get test hUSDCPassed · 2 min ago
Connect a walletPassed · 2 min ago
Add a testWe write the steps from your answers and run the test right away.
What does the user do?One thing, start to finish.
Withdraw half of the deposit from the vault
How do you know it worked?What the page shows at the end. We check it on every run.
Position shows about 125 hvUSDC, share price didn’t drop
OptionalWhat you leave out, we work out from the app.
Where does it start?The page the test opens first.
/vault
Any steps we should follow?One per line, the way a user would say them.
Open the Withdraw tabEnter half of your positionClick Withdraw
It runs as soon as the steps are written.
Cancel
Write and run
Runs every test with its own wallet on a local fork. Real contracts.
Forks of six chains today
DappDrillHarbor Labs/Harbor Vault
TestsRunsSettings
H
Tests
Deposit hUSDC into the vault
RunDuplicate
Passed · 2 min ago · took 41s · fork of Ethereum
Goal
Deposit 250 hUSDC on the Vault page and confirm the position grows.
Expected result
The position shows 250 hUSDC deposited and the wallet shows 750 hUSDC.
“Your position” reads 242.43 hvUSDC, worth 250 hUSDC; the header shows 750 hUSDC.
Enter 250 as the deposit amountType “250” into “Amount”
Click Approve 250 hUSDCConnect the wallet if asked, then click “Approve 250 hUSDC”
Approve in the walletApprove hUSDC for HarborVault 0xe7f1…0512
Click DepositClick “Deposit”
Confirm in the walletDeposit 250 hUSDC to HarborVault 0xe7f1…0512
Harbor Vault
VaultRewardsActivity
0x7a3F…41e1
DepositWithdraw
Amount
250hUSDC
Balance 1,000 hUSDCGet test hUSDC
Confirm in wallet…
You receive about 242.43 hvUSDC
12.50 hUSDC to claim5% bonus on every deposit
Claim rewards
hUSDC VaultDeposit hUSDC and earn yield. Withdraw any time.
TVL102,418
APY4.8%
Share price1.0312
Your position0.00 hvUSDCworth 0.00 hUSDC
Test wallet0x7a3F…41e1
Deposit250 hUSDC
ToHarborVault 0xe7f1…0512
NetworkEthereum (fork)
RejectConfirm
0:26 / 0:41
Wallet3
Connect0x7a3F…41e1 on Ethereum (fork)
Approved
Approve hUSDCFor HarborVault 0xe7f1…0512
Approved
Deposit 250 hUSDCTo HarborVault 0xe7f1…0512
Approved
Replays each flow the way users break it: rejected, wrong network, switched account, slow RPC.
DappDrillHarbor Labs/Harbor Vault
TestsRunsSettings
H
Tests / Deposit hUSDC into the vault
Rejected in wallet
Run
Failed · 2 min ago · took 17s · checked again in a fresh browser
Rejected in walletSlow RPCWrong networkSwitched accountNot enough gas
Expected result
The page says the deposit was cancelled, and Deposit can be clicked again.
The button stays on “Confirming…” and nothing on the page mentions the reject.
Enter 250 as the deposit amountType “250” into “Amount”
Approve in the walletApprove hUSDC for HarborVault 0xe7f1…0512
Click DepositClick “Deposit”
Reject in the walletThe wallet answers 4001, user rejected the request
Deposit can be clicked againStill “Confirming…” after the reject
Harbor Vault
VaultRewardsActivity
0x7a3F…41e1
DepositWithdraw
Amount
250hUSDC
Balance 1,000 hUSDCGet test hUSDC
Confirming…
You receive about 242.43 hvUSDC
12.50 hUSDC to claim5% bonus on every deposit
Claim rewards
hUSDC VaultDeposit hUSDC and earn yield. Withdraw any time.
TVL102,418
APY4.8%
Share price1.0312
Your position0.00 hvUSDCworth 0.00 hUSDC
0:15 / 0:17
Wallet3
Connect0x7a3F…41e1 on Ethereum (fork)
Approved
Approve hUSDCFor HarborVault 0xe7f1…0512
Approved
Deposit 250 hUSDCTo HarborVault 0xe7f1…0512
Rejected
Runs again from CI on every commit or release, and every day on your live app. When a test stops passing, you hear about it in Slack, Telegram or email.
DappDrillHarbor Labs/Harbor Vault
TestsRunsSettings
H
RunsEvery time Harbor Vault’s tests ran: from CI, by you, after exploring, or on the daily schedule.
CI · a3f9e1c Show deposit status11 of 14 passed · 3 failed
14 results · 2 min ago · 4 min
Daily run14 of 14 passed
14 results · 6 h ago · 4 min
CI · 7c21d08 Fix rewards rounding14 of 14 passed
14 results · yesterday · 4 min
Daily run14 of 14 passed
14 results · yesterday · 5 min
Run by you14 of 14 passed
14 results · 2 days ago · 4 min
Daily run14 of 14 passed
14 results · 2 days ago · 4 min
Daily run14 of 14 passed
14 results · 3 days ago · 4 min
Harbor Vault: 3 conditions stopped passing
DappDrill <alerts@dappdrill.com>to team@harborlabs.xyz
09:04
After a3f9e1c (Show deposit status), from CI:
- Deposit · Rejected in wallet: stays on “Confirming…”- Deposit · Wrong network: sent without asking to switch- Withdraw · Not enough gas: nothing happens, no message
app.dappdrill.com/apps/harbor-vault

In CI

Runs on every change.

The same tests from the CLI or a GitHub Action, with JUnit, JSON and Markdown reports.

$ dappdrill run --unhappy

Running 14 tests on https://harborvault.xyz

✓Deposit hUSDC into the vault41s

✓Withdraw hUSDC38s

✓Withdraw half of the deposit35s

✓Claim the deposit bonus22s

✓Get test hUSDC9s

✓Connect a wallet6s

✗Deposit hUSDC into the vault · Rejected in wallet17s

The Deposit button stays on “Confirming…” after the wallet rejects.

✓Deposit hUSDC into the vault · Slow RPC58s

✗Deposit hUSDC into the vault · Wrong network12s

The deposit was sent without asking to switch networks.

✓Deposit hUSDC into the vault · Switched account24s

✓Deposit hUSDC into the vault · Not enough gas14s

✓Withdraw hUSDC · Rejected in wallet16s

✓Withdraw hUSDC · Slow RPC52s

✗Withdraw hUSDC · Not enough gas13s

Clicking Withdraw does nothing and shows no message.

11 of 14 passed, 3 failed. Videos and screenshots: dappdrill-out/artifacts

.github/workflows/dappdrill.yml

- uses: dappdrill/dappdrill/.github/actions/dappdrill@main
  with:
    url: ${{ steps.preview.outputs.url }}
    unhappy: "true"

The contract

Audited, fuzzed, proven, bountied.

Audits
Fuzzing and invariant tests
Formal verification
Bug bounties after launch

The screen

Clicked through by hand, the day before release.

What happens when the user rejects?
Wrong network? A switched account?
Two wallets installed?
A slow RPC?

On live frontends

Most bugs aren’t attacks. They’re a real user doing something unexpected.

Compound / Slow RPC
One click sent two deposits.
two supply() calls, 6 ms apart
Supply
1 clicksupply() ×2
Compound / Two wallets
The user picked MetaMask. The app talked to Rabby.
EIP-6963 choice ignored
dApp
MetaMask picked
Rabby used
pod / Wrong network
Sign-in hangs on “Connecting…” forever.
no switch prompt, no message
Connecting…3:02

Found by DappDrill on live frontends, run on local forks, November 2026. Each finding checked by hand.

A QA engineer that understands crypto and wallets.

Runs on every change.

Audited, fuzzed, proven, bountied.

Clicked through by hand, the day before release.

Most bugs aren’t attacks. They’re a real user doing something unexpected.

Paste a URL. Get a bug report.