> ## Documentation Index
> Fetch the complete documentation index at: https://docs.peec.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# GPT-5.6 retrieval changes — more iterations, double the sources

> David Konitzny's analysis (Aug 2026) — with GPT-5.6, single fan-out prompts dropped from 94% to 43.5%, second iterations rose to 33.5%, and sources retrieved per prompt doubled from ~12 to ~24.

GPT-5.6 (Luna), ChatGPT's default model for Free and Go users since early August 2026, retrieves fundamentally differently from GPT-5.5. David Konitzny's analysis ([full article](https://www.linkedin.com/pulse/chatgpts-new-default-model-gpt-56-more-retrieval-content-konitzny-8htce/), Aug 2026) documents the shift:

* **Multi-iteration retrieval is the new default.** Prompts needing only a single query fan-out dropped from **94.0% (GPT-5.5) to 43.5% (GPT-5.6)**. Second iterations rose from \~5% to **33.5%**; three iterations from 0.1% to 7.4%; even 6–10+ iterations (7.2% combined) are now measurable. Some sessions resemble a lightweight Deep Research.
* **Sources retrieved per prompt doubled** from \~12 to \~24, expanding the pool of domains that can enter answers.
* **Fan-out patterns shifted:** the `site:` operator now appears in 23% of fan-outs (vs 0.3% before), "official" rose from \~5% to 9%, and the current year appears in 28.6%. "Best" fell from \~20% to 9.9% in *share*, but its absolute count stayed constant — the denominator grew.

The practical consequence: visibility metrics fluctuated during the rollout because more retrieval iterations mean more chances for domains to enter or leave answers. What GPT-5.6 retrieves also changed — product pages overtook listicles; see [GPT-5.6 retrieves product pages over listicles](/research/gpt-56-product-pages-vs-listicles) and [ChatGPT site-operator fan-outs](/research/chatgpt-site-operator-fanouts).

**Source:** [ChatGPT's new default model GPT-5.6: More retrieval, more fan-outs, more first-party content](https://www.linkedin.com/pulse/chatgpts-new-default-model-gpt-56-more-retrieval-content-konitzny-8htce/), David Konitzny, LinkedIn, Aug 2026.