Spec mismatch

0xC6dd99dC547a1dA35Bd777eA5CEe5c080667db47

0xC6dd99dC547a1dA35Bd777eA5CEe5c080667db47Monad testnet

1 of 30 properties failed at block 69,207,426. The vault's behavior contradicts an EIP-4626 MUST sentence.

Created by Specfirst DemoVaultFactory in block 68,922,607; the watcher found it 2026-10-07 08:27 UTC. First deposit seen in block 68,922,734. It was not on the hand-made list the board started from.

Request a re-checkThis report comes from a check the watcher ran on its own on 2026-10-08; nobody asked for it.

What failed

previewDepositEIP-4626 MUST
Forge found a counterexample: Error: a >=~ b not satisfied [uint]
Counterexample: test_previewDeposit(([0xB816CD016734A139Eeed23597dAb8555e6989586, 0xD8078DAc792054a290b331bd0Cda1b15F6205C61, 0x5B8C1187e07C7E9AffEa888969fCF858d034eFd9, 0xB63EdfEd0BBAA8E8265e49b9ed94C98D175623df], [86037699282067532405206065311250058561965662252683, 12832996, 706313317268216969039886190178827, 24852726738788757585], [30542258758056153007, 2141, 4552210412625778, 115792089237316195423570985008687907853269984665640564039457584007913129639933], -3425687336439), 5462468400616)

A spec mismatch is a disagreement with an EIP-4626 MUST sentence, shown by a concrete call. It is not a claim that funds are at risk.

What the watcher saw

Every event the watcher recorded for this vault, newest first. Each check is a statement about one block; a re-check with the same outcome is recorded here without a new attestation.

08:27:2310-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,207,426, 9 s. Report
Why: subscriber re-check.
08:27:1410-08Queued
Waiting for a check: subscriber re-check.
08:26:1710-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,207,211, 8 s. Report
Why: subscriber re-check.
08:26:0810-08Queued
Waiting for a check: subscriber re-check.
08:25:1110-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,206,992, 8 s. Report
Why: subscriber re-check.
08:25:0210-08Queued
Waiting for a check: subscriber re-check.
08:24:0910-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,206,793, 8 s. Report
Why: subscriber re-check.
08:24:0110-08Queued
Waiting for a check: subscriber re-check.
08:23:0310-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,206,574, 8 s. Report
Why: subscriber re-check.
08:22:5510-08Queued
Waiting for a check: subscriber re-check.
08:21:5610-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,206,358, 6 s. Report
Why: subscriber re-check.
08:21:4910-08Queued
Waiting for a check: subscriber re-check.
08:20:5810-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,206,156, 9 s. Report
Why: subscriber re-check.
08:20:4810-08Queued
Waiting for a check: subscriber re-check.
08:19:5010-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,205,941, 7 s. Report
Why: subscriber re-check.
08:19:4210-08Queued
Waiting for a check: subscriber re-check.
08:18:5010-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,205,740, 9 s. Report
Why: subscriber re-check.
08:18:4110-08Queued
Waiting for a check: subscriber re-check.
08:17:4810-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,205,538, 9 s. Report
Why: subscriber re-check.
08:17:3910-08Queued
Waiting for a check: subscriber re-check.
08:16:4210-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,205,321, 9 s. Report
Why: subscriber re-check.
08:16:3310-08Queued
Waiting for a check: subscriber re-check.
08:15:4010-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,205,114, 8 s. Report
Why: subscriber re-check.
08:15:3010-08Queued
Waiting for a check: subscriber re-check.
08:14:3910-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,204,907, 11 s. Report
Why: subscriber re-check.
08:14:2610-08Queued
Waiting for a check: subscriber re-check.
08:13:2710-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,204,687, 7 s. Report
Why: subscriber re-check.
08:13:2010-08Queued
Waiting for a check: subscriber re-check.
08:12:2410-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,204,483, 8 s. Report
Why: subscriber re-check.
08:12:1510-08Queued
Waiting for a check: subscriber re-check.
08:11:2310-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,204,288, 8 s. Report
Why: subscriber re-check.
08:11:1510-08Queued
Waiting for a check: subscriber re-check.
08:10:2210-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,204,087, 9 s. Report
Why: subscriber re-check.
08:10:1310-08Queued
Waiting for a check: subscriber re-check.
08:09:1810-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,203,878, 9 s. Report
Why: subscriber re-check.
08:09:0910-08Queued
Waiting for a check: subscriber re-check.
08:08:1710-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,203,679, 8 s. Report
Why: subscriber re-check.
08:08:0810-08Queued
Waiting for a check: subscriber re-check.
08:07:1510-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,203,472, 9 s. Report
Why: subscriber re-check.
08:07:0610-08Queued
Waiting for a check: subscriber re-check.
08:06:1310-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,203,264, 11 s. Report
Why: subscriber re-check.
08:06:0110-08Queued
Waiting for a check: subscriber re-check.
08:05:1410-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,203,057, 15 s. Report
Why: subscriber re-check.
07:59:5410-08Error
check failed (attempt 1 of 3), retrying from 2026-10-08T08:04:54.409Z: ENOSPC: no space left on device, open '/Users/jaemin/Developer/Personal/specfirst-batch/.specfirst/checks/10143/0xc6dd99dc547a1da35bd777ea5cee5c080667db47/.69202025.forge.json.tmp-86636-e33008df'
07:59:4310-08Queued
Waiting for a check: subscriber re-check.
07:58:4910-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,201,814, 8 s. Report
Why: subscriber re-check.
07:58:4010-08Queued
Waiting for a check: subscriber re-check.
07:57:4110-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,201,585, 10 s. Report
Why: subscriber re-check.
07:57:3110-08Queued
Waiting for a check: subscriber re-check.
07:56:3510-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,201,366, 10 s. Report
Why: subscriber re-check.
07:56:2410-08Queued
Waiting for a check: subscriber re-check.
07:55:3110-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,201,156, 9 s. Report
Why: subscriber re-check.
07:55:2010-08Queued
Waiting for a check: subscriber re-check.
07:54:2110-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,200,941, 6 s. Report
Why: subscriber re-check.
07:54:1510-08Queued
Waiting for a check: subscriber re-check.
07:53:2210-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,200,732, 10 s. Report
Why: subscriber re-check.
07:53:1110-08Queued
Waiting for a check: subscriber re-check.
07:52:1410-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,200,511, 9 s. Report
Why: subscriber re-check.
07:52:0410-08Queued
Waiting for a check: subscriber re-check.
07:51:1110-08Checked
Spec mismatch
29 pass, 1 fail, 0 inconclusive, 0 not applicable at block 69,200,305, 9 s. Report
Why: subscriber re-check.

JSON: this vault's history

All 30 properties

In report order. Bit i is the bit the registry's passedBitmap and failedBitmap use for that property.

Bit	Property	Result	What was found
a16z/erc4626-tests at ac48546, 26 properties: 16 on EIP-4626 MUST sentences, 10 on SHOULD guidance (the round trips and the allowance checks)
0	`asset`test_assetEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: asset() does not revert
1	`totalAssets`test_totalAssetsEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: totalAssets() does not revert
2	`convertToShares`test_convertToSharesEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: convertToShares gives the same result for any caller
3	`convertToAssets`test_convertToAssetsEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: convertToAssets gives the same result for any caller
4	`maxDeposit`test_maxDepositEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: maxDeposit does not revert
5	`previewDeposit`test_previewDepositEIP-4626 MUST	Fail	Forge found a counterexample: Error: a >=~ b not satisfied [uint] Checks: deposit mints at least the shares previewDeposit quoted Raw result reason: Error: a >=~ b not satisfied [uint] runs: 0 call: test_previewDeposit(([0xB816CD016734A139Eeed23597dAb8555e6989586, 0xD8078DAc792054a290b331bd0Cda1b15F6205C61, 0x5B8C1187e07C7E9AffEa888969fCF858d034eFd9, 0xB63EdfEd0BBAA8E8265e49b9ed94C98D175623df], [86037699282067532405206065311250058561965662252683, 12832996, 706313317268216969039886190178827, 24852726738788757585], [30542258758056153007, 2141, 4552210412625778, 115792089237316195423570985008687907853269984665640564039457584007913129639933], -3425687336439), 5462468400616) calldata: 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 log: Error: a >=~ b not satisfied [uint] log: Value a: 5462468400616 log: Value b: 5517093084622 log: Max Delta: 0 log: Delta: 54624684006
6	`deposit`test_depositEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: deposit moves assets from the caller, credits shares to the receiver and spends allowance
7	`maxMint`test_maxMintEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: maxMint does not revert
8	`previewMint`test_previewMintEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: mint pulls at most the assets previewMint quoted
9	`mint`test_mintEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: mint moves assets from the caller, credits shares to the receiver and spends allowance
10	`maxWithdraw`test_maxWithdrawEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: maxWithdraw does not revert
11	`previewWithdraw`test_previewWithdrawEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: withdraw burns at most the shares previewWithdraw quoted
12	`withdraw`test_withdrawEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: withdraw burns owner shares, pays the receiver and spends share allowance
13	`withdraw-zero-allowance`test_withdraw_zero_allowanceEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: withdraw on behalf of an owner without allowance reverts
14	`maxRedeem`test_maxRedeemEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: maxRedeem does not revert
15	`previewRedeem`test_previewRedeemEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: redeem pays at least the assets previewRedeem quoted
16	`redeem`test_redeemEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: redeem burns owner shares, pays the receiver and spends share allowance
17	`redeem-zero-allowance`test_redeem_zero_allowanceEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: redeem on behalf of an owner without allowance reverts
18	`RT-deposit-redeem`test_RT_deposit_redeemEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: redeem(deposit(a)) returns no more than a
19	`RT-deposit-withdraw`test_RT_deposit_withdrawEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: withdraw(a) burns at least the shares deposit(a) minted
20	`RT-redeem-deposit`test_RT_redeem_depositEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: deposit(redeem(s)) mints no more than s
21	`RT-redeem-mint`test_RT_redeem_mintEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: mint(s) costs at least the assets redeem(s) paid
22	`RT-mint-withdraw`test_RT_mint_withdrawEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: withdraw(mint(s)) burns at least s shares
23	`RT-mint-redeem`test_RT_mint_redeemEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: redeem(s) pays no more than mint(s) cost
24	`RT-withdraw-mint`test_RT_withdraw_mintEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: mint(withdraw(a)) costs at least a
25	`RT-withdraw-deposit`test_RT_withdraw_depositEIP-4626 SHOULD	Pass	No counterexample in 16 fuzz runs at this block. Checks: deposit(a) mints no more than the shares withdraw(a) burned
Specfirst max-honored properties, MIT, each on one EIP-4626 MUST sentence about a max function
26	`sf-maxDeposit-honored`test_sf_maxDeposit_honoredEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: deposit goes through up to min(maxDeposit, 1e6 tokens); when a smaller amount is refused the bound must go through, and refusals are counted (EIP-4626: maxDeposit MUST NOT be higher than what deposit accepts)
27	`sf-maxMint-honored`test_sf_maxMint_honoredEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: mint goes through up to min(maxMint, shares of 1e6 tokens); when a smaller amount is refused the bound must go through, and refusals are counted (EIP-4626: maxMint MUST NOT be higher than what mint accepts)
28	`sf-maxWithdraw-honored`test_sf_maxWithdraw_honoredEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: withdraw goes through up to maxWithdraw; when a smaller amount is refused maxWithdraw must go through, and refusals are counted (EIP-4626: maxWithdraw MUST NOT be higher than what withdraw accepts, and MUST be 0 when withdrawals are disabled)
29	`sf-maxRedeem-honored`test_sf_maxRedeem_honoredEIP-4626 MUST	Pass	No counterexample in 16 fuzz runs at this block. Checks: redeem goes through up to maxRedeem; when a smaller amount is refused maxRedeem must go through, and refusals are counted (EIP-4626: maxRedeem MUST NOT be higher than what redeem accepts, and MUST be 0 when redemptions are disabled)

Onchain attestation

Attestation #27 Valid

It records a different report, for block 68,924,274. This page shows block 69,207,426.

isCompliant is false: the attested report has failing, inconclusive or not applicable properties.

Issued: 2026-10-07 08:35 UTC
Issuer: 0x915a...bEA3
Counts: 29 pass, 1 fail, 0 inconclusive, 0 n/a
reportHash: 0x297066...1f67a7
suiteHash: 0x67de68...c66d91
Transaction: not recorded here; look for Attested id 27 in the registry's logs
Registry: 0x3754...daF7

Report at the attested reportURI

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Replay this check

specfirst check 0xC6dd99dC547a1dA35Bd777eA5CEe5c080667db47 \
  --standard erc4626 \
  --block 69207426 \
  --runs 16 \
  --seed 0x680957995ee26cccfb1665a0083df67c71e478c10c2ae9d7af5c307db98f9a41 \
  --network monad-testnet

Same block, runs and seed. The CLI draws a fresh random sender each run; the seed also salts the 16-user pool.

Report JSON

reportHash 0x16a69a...690177 is keccak256 of the report's canonical JSON (RFC 8785), the value the registry stores.

Badge and API

The badge and the JSON read the registry when they are loaded, so they follow new attestations without a rebuild.

[![Specfirst ERC-4626 check](/badge/check/10143/0xc6dd99dc547a1da35bd777ea5cee5c080667db47.svg)](/v/10143/0xc6dd99dc547a1da35bd777ea5cee5c080667db47)

JSON API Badge SVG

Implementation

Proxy: Not a proxy
Implementation key: 0x8a88cfb645d81c78aafc8fa247fcda64c74beee4ed0c86c812334dcd4c0d344d
Key from: The vault's own code: same compiler metadata and same code with immutables masked
Code hash: 0xa9c0dbb0c62fd6787e09a547ac4e1e17595e97228efed503a1636cb3e9842ff4
Code size: 4,222 bytes
Same key: No other vault on this board

Run

Block: 69,207,426, Monad testnet
Seed: 0x680957995ee26cccfb1665a0083df67c71e478c10c2ae9d7af5c307db98f9a41
Sender: 0x22995726d5Dce0a786849BDFfc265b320326088C
Runs: 16 per property
Delta: 0 base units
Forge: forge Version: 1.5.1-Homebrew
forge-std: bf647bd6046f
Reject limit: 4096
Harness: 0xf5d1ee...8d0262
sf properties: 0x1d721e...dfa233
suiteHash: 0x67de68...c66d91
Started: 2026-10-08 08:27 UTC, 9 s
Report: schemaVersion 4