A place for talking about the Ethereum Virtual Machine on Farcaster.

what is the most reliable way of attaching metadata to an ethereum transaction?

cases that need to be handled:
1. EOA tx
2. UserOp
3. batch call directly on smart account

calldata suffix is the first thing that comes to mind but fetching userops is potentially expensive and it requires tracing to handle (3)

can you build in event emission or are you trying to retrofit this to an existing smart contract?  if the latter, can you route transactions through a new smart contract that emits your metadata event before calling the  intended smart contract's method?

If you don't have control of the target method at all but are involved in initially building the transaction, I think calldata might be the only way.