Truncated page markup is rejected instead of saved

Writing markup replaces a page's whole content tree, so a payload that got cut off partway, usually at an LLM output-token cap, used to return 200 OK and save the surviving prefix as the entire page. Trailing sections disappeared and the interrupted one came back rebuilt from blank defaults. A cut-off payload now returns 400 naming the reason and the line it stopped on, and the page is left exactly as it was. This covers pages and blog posts, on create and update.

If what you actually want is to add a tracking pixel or a snippet of custom code, do not rewrite markup for it. head_code, footer_code and custom_css take an append mode and leave the page's content alone, which is both safer and a much smaller request.

Agent examples: add a Meta or Google pixel to a live funnel page without touching its content · fail loudly when a generated page comes back cut off, instead of shipping half a page to a customer.

Resources: Page
Building with an AI agent? Point it at the Pages skill.