Currently, if mongod receives a request with autocommit:false and a txnId (txnNumber/lsid pair) that has not been seen yet, it will return ErrorCodes::NoSuchTransaction. If a retryable write with the same txnId was completed earlier on that session though, the request with autocommit:false would instead return ErrorCodes::InvalidOptions.

Running a command with autocommit:false and a txnId is a valid combination of options and it isn't really intuitive for a retryable write to change the error code, so I think the code should always be NoSuchTransaction.