Handle Errors

This guide explains how to handle operation errors, handle requirement errors, and follow best practices for disposing wallet state.

Operation errors

You can catch failures from supply(), withdraw(), supplyCollateral(), borrow(), repay(), and withdrawCollateral() with try/catch:

Handle a failed supply

try {
  await morpho.supply({
    token: '0xdAC17F958D2ee523a2206206994597C13D831ec7',
    amount: 0n
  })
} catch (e) {
  console.error('Morpho lending failed:', e.message)

  if (e.message.includes('amount')) {
    console.log('Amount must be greater than zero')
  }
}

Common failure causes include:

wallet account does not have a provider configured
write method is called with a read-only account
token does not match the configured vault asset, market loan token, or market collateral token
explicit target is used without the required chainId
connected chain does not match the configured Morpho target
amount is zero, invalid, or larger than the account balance
onBehalfOf or to does not match the connected wallet address when required

Use this checklist to map the most common failures to fixes:

Symptom	Likely cause	Fix
Constructor fails before any operation	Wallet account has no provider	Create the EVM account with a provider or use a read-only account with an RPC provider
Write method fails on a read-only account	Read-only account can quote and read, but cannot send transactions	Use `WalletAccountEvm` or `WalletAccountEvmErc4337` for mutating methods
Explicit target fails during setup	`chainId` is missing, invalid, or does not match the wallet chain	Pass the expected `chainId` with `earnVaultAddress`, `borrowMarketId`, or `borrowMarketParams`
Token mismatch error	The supplied token is not the configured vault asset, market loan token, or collateral token	Use the token from the configured vault or market target
Zero amount error	`amount` and `nativeAmount` are both absent or zero	Pass a positive ERC-20 `amount`, a positive `nativeAmount`, or `amount: "max"` for repay
Requirement lookup returns approval or authorization	Allowance, permit, Permit2, or Morpho authorization is missing	Send returned transaction requirements or sign the returned signature requirement before the final action
Final action fails after requirements	Allowance, balance, signature, authorization, quote, or market state changed after the requirement lookup	Re-run the matching `get*Requirements()` method and rebuild the final action
Quote succeeds but write fails	On-chain state changed, the account lacks balance, or requirements were not satisfied	Re-check requirements, balances, token addresses, and chain before sending

Requirement errors

Requirement helpers can fail if the configured target, token, account, or provider cannot produce a valid Morpho SDK action.

Handle requirement errors

try {
  const requirements = await morpho.getBorrowRequirements({
    token: '0xdAC17F958D2ee523a2206206994597C13D831ec7',
    amount: 1000000n
  })

  console.log('Borrow requirements:', requirements)
} catch (e) {
  console.error('Requirement lookup failed:', e.message)
}

If a final action fails after requirements were returned, re-check the requirements. Allowances, signatures, authorizations, or on-chain market state can change between the requirement lookup and the final transaction.

Quote errors

You can isolate quote failures from write failures when you only need an estimate:

Handle quote errors

try {
  const quote = await morpho.quoteBorrow({
    token: '0xdAC17F958D2ee523a2206206994597C13D831ec7',
    amount: 1000000n
  })

  console.log('Borrow fee:', quote.fee)
} catch (e) {
  console.error('Quote failed:', e.message)
}

See Rules & Notes for address, token, amount, and target validation expectations.

Best Practices

Dispose wallet secrets after a lending session by calling dispose() on WalletAccountEvm, or the matching dispose method on your smart account type.

Dispose after a Morpho lending session

try {
  await morpho.supply({
    token: '0xdAC17F958D2ee523a2206206994597C13D831ec7',
    amount: 1000000n
  })
} finally {
  account.dispose()
}

For ERC-4337 accounts, use dispose() on the smart-account type. Clear references to MorphoProtocolEvm when the session ends.

Handle Errors

Operation errors

Requirement errors

Quote errors

Best Practices

Next Steps

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