ChatGPT search now uses site: operator at scale, Promptwatch data shows
Promptwatch, a monitoring service in the emerging GEO (Generative Engine Optimization) space, reports that the share of ChatGPT Search queries containing the site: operator jumped from 0.3-0.5% to 16-17% on August 8, 2026, coinciding with the GPT-5.6 rollout. The change suggests a significant shift in how ChatGPT's search product handles site-specific queries.
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Simon Willison
ChatGPT search now uses the site:operator at scale Promptwatch is part of the emerging "GEO" space, for Generative Engine Optimization - the chatbot version of SEO, where companies offer tools and consulting to help your site increase its presence in replies to prompts inside tools like ChatGPT. The Promptwatch product uses automation to track responses to prompts across end-user chat products like ChatGPT, Claude, and Gemini. They publish aggregate reports on this as part of their own content marketing strategy, which do seem to provide credible hints as to otherwise invisible design changes to those products. Their own tracking shows a notable change aligned with the GPT-5.6 rollout earlier this month: The percentage of all ChatGPT Search fanout queries that contain the site:operator, per day. The share hovered between 0.3% and 0.5% for weeks, dipped briefly to 0.15% on August 3 to 5 (consistent with a staged rollout or pre-launch experiment), then jumped to 16-17% on August 8. It's