Can I use this to write solidity contracts ?
It seems like a safe playground, maybe it will lose a few tokens, but if they are no legal consequences, who cares ? The best place to move fast and break things, and with great reward potential.
If I take some freelancer to write them what's telling me that they are not already using something like codex or copilot. It's like when a factory release its used water in the river nearby. Maybe we shouldn't drink from the river anymore, but it would be better to test the water the factory release to make sure it's OK.
Codex in its current form is meant to be used as an assist for someone who can already code/debug, not as a replacement for a contractor.
In theory you can create a new token per contract to cap the maximum potential loss. Then you increase this maximum potential loss as the contract get used in the open and therefore become more robust.
You probably can write some guarantee fund smart contract to compensate for when bug happen.
Sooner or later we will have to implement a high-level error-correction mechanism to handle the bugs generated by the weak AI : Like a paradigm shift where you expect bugs to happen and handle them instead of expecting no bugs.
If codex is able to handle a generic api from reading the doc, it maybe could use a python library for solidity contracts like https://web3py.readthedocs.io/en/stable/contracts.html
As a contract user, I'd probably have more trust in a contract written by an independent AI from a short natural language specification which can't hide intent, than a contract with hidden backdoor, or a subtle bug.
Also the AI will probably improve with usage.
You probably can generate multiple version of your contract, and maybe a high level bug correction scheme like taking the median action between those version can increase bug robustness and find those edge cases when action differ.