Discussion EIP-3668: Use of CCIP read for transactions (CCIP write)

Earlier this year ethers.js added support for EIP-3668. A few other clients followed.

It appears to be the case that most clients decided to only support eth_call even though EIP-3368 mentions the “use of CCIP read for transactions”:

While the specification above is for read-only contract calls (eg, eth_call ), it is simple to use this method for sending transactions (eg, eth_sendTransaction or eth_sendRawTransaction ) that require offchain data. While ‘preflighting’ a transaction using eth_estimateGas or eth_call , a client that receives an OffchainLookup revert can follow the procedure described above in Client lookup protocol, substituting a transaction for the call in the last step. This functionality is ideal for applications such as making onchain claims supported by offchain proof data.

We think using EIP-3668 for “write” transactions is powerful, especially when combined with EIP-712 for offchain signing of payloads returned by the Gateway.

What could be done to emphasize the support for eth_sendTransaction? Would it be helpful to create a new “EIP - CCIP Write” or is the existing EIP good enough?