`responses` corrupts previous conversations `assistant` item

The developer and system roles are not the same, but with regards to whether that’s the cause of the problem, it’s not.

Even with all developer messages, or with no developer messages, as soon as I call the Responses end point after inserting synthetic assistant messages, the synthetic messages are corrupted/ignored/removed.

I take your point of leaving it unresolved and have marked it as such, I wasn’t aware staff review these threads. Even if they don’t classify it as a bug, they should at least update their documentation.