Chances are whatever was needed to make earlier models perform well now either is no longer helping much or actively hurts performance (worse results, slower, uses more tokens …).
Example: for large Eloqua/Marketo/HubSpot emails we would previously make a planner which delegated the sections to their own call.
GPT5.6 can do the whole thing. The planner is unhelpful.
My suggestion: feature flag your complex implementations so you can rapidly contrast with and without it. (Or a formal eval suite if you have one).
If you prefer the simpler path, delete the old path.
Note: the challenge is making things compatible with these tools. Obviously generating html directly has been simple for ages.
(Source: mopsy.ai)