@abi.decodeCall

Decode calldata into [contract signature [args]] with human-readable EVML values.

On-chain (@abi.decodeCall!): Takes an inline signature and a lens instead of fetching an ABI; checks the selector on-chain (a mismatch reverts) and returns only the selected argument.

Returns: any

Syntax

@abi.decodeCall(contract calldata)

Arguments

Name	Type	Description
contract	address	Contract the calldata targets (its verified ABI is used)
calldata	bytes	Full calldata including the 4-byte function selector

Examples

# Decode a token transfer
set [$to $sig $args] @abi.decodeCall(0xe91D153E0b41518A2Ce8Dd3D7944Fa863463a97d 0xa9059cbb000000000000000000000000000000000000000000000000000000000000dead0000000000000000000000000000000000000000000000000de0b6b3a7640000)
print $sig

On-chain face

@abi.decodeCall! judges a live calldata blob: a queued Safe transaction, a timelock payload, a governor action. It takes a different argument shape than the off-chain face, because nothing can fetch an ABI at judge time — the signature comes inline, the bang convention ::! also follows:

@abi.decodeCall!(<calldata expression> name(argTypes) [_ $])

• The signature is inline and the selector is CHECKED. Decoding foreign calldata as the wrong function would read plausible garbage (an approve decoded as transfer yields a well-formed address), so the compiled form compares the calldata's first four bytes against the declared signature's selector and reverts on mismatch — the failure carries the actual selector found.
• A [_ $] lens is required, selecting one call argument; array selections are refused, and the calldata argument must be a live call or bytes expression.

# The queued transaction transfers to the treasury, whatever the amount
assert @abi.decodeCall!(0xe91D153E0b41518A2Ce8Dd3D7944Fa863463a97d::{queuedCalldata()(bytes)} transfer(address,uint256) [$ _]) == @token(DAI)

The argument words of calldata sit four bytes off word alignment, so the compiled form slices the selector away with a live length, re-enters the realigned args tuple through the core's PAYLOAD sentinel, and navigates the signature's input types. The calldata expression is resolved more than once along the way (the length read, the slice, the selector check): the cost of expressions being trees, paid per assertion.

See Also

• @abi.encodeCall — the inverse: encode a call from signature and args
• @abi.decode — decode raw ABI data given a type list
• @ens — resolve the @ens(name) values back to addresses