Segonzac: Inside ChatGPT Search

Key Takeaways:

• Segonzac (RESONEO) published a full technical study on how ChatGPT works and what changed when GPT-5.4 was introduced on 04.03.2026 and GPT-5.3 became the new default:

  • Average domains dropped by -20% - fewer domains share the visibility in ChatGPT answers - which is also supported by Crawl log data from ChatGPT User Agents

  • Query Fan-Out changed and includes site: Parameters to filter highly relevant or authorative sites

  • Single tool web.run evolved into 12 operations including find, click, screenshot for navigation

  • Different behaviour for GPT-5.2 v. 5.3 vs. 5.4 while having the same training cutoff of August 2025: Parametric vs. dynamic visibility (what the model knows/search off vs. what the model finds/search on)

• Optimization for Parametric Visibility: Training Data

  • PR and press relations

  • Authoritative editorial content

  • Wikipedia / Wikidata

  • Reference publications

  • Branding and positioning

• Optimization for Dynamic Visibility: Search Retrieval

  • Technical SEO

  • Snippet optimization

  • Sponsored placements

  • Continuous monitoring

  • Geo and model segmentation

Sources:

• https://www.linkedin.com/posts/resoneo_we-just-published-inside-chatgpt-search-activity-7446612211680071680-6UtL

• https://think.resoneo.com/chatgpt/5.3-5.4/