GPT-5 is an integrated model, so users do not need to choose between GPT-4o, o3 or o4 mini in the model switcher.

True if, as of 2025-08-14, GPT-5 in ChatGPT worked as one unified system that automatically routed queries or decided how much reasoning to use, so that by default users did not have to choose between GPT-4o, o3, o4-mini or similar models in the model switcher, per OpenAI's documentation. Mostly true if GPT-5 was the unified default but legacy models (e.g., GPT-4o) or GPT-5 mode options (Auto/Fast/Thinking) remained selectable for some users, so choosing was optional rather than needed, or if the 'integrated' design was technically a router across several sub-models, not one single model. Mixed if the unified experience applied only to some user tiers while others still had to choose among models. Mostly false if users generally still needed to pick between reasoning and non-reasoning models to get the right behaviour. False if GPT-5 was not offered as a unified or default system and the old model switcher choice was unchanged.

Set before the research began.

1. E1 Introducing GPT-5 OpenAI · 7 August 2025 Own record

   “GPT‑5 is the new default in ChatGPT, replacing GPT‑4o, OpenAI o3, OpenAI o4-mini, GPT‑4.1, and GPT‑4.5 for signed-in users.”

2. E2 Introducing GPT-5 OpenAI · 7 August 2025 Own record

   “GPT‑5 is a unified system with a smart, efficient model that answers most questions, a deeper reasoning model (GPT‑5 thinking) for harder problems, and a real‑time router that quickly decides which to use”

3. E3 ChatGPT Plus Users Get Access To More Legacy Models In Updated GPT-5 Experience BGR · 13 August 2025

   “You can now choose between "Auto", "Fast", and "Thinking" for GPT-5. Most users will want Auto, but the additional control will be useful for some people.”

4. E4 GPT-5 launch sparks backlash as OpenAI removes ChatGPT model choice | Digital Watch Observatory Digital Watch Observatory · 9 August 2025

   “GPT-5 includes both an efficient and a reasoning model, but users no longer choose which to engage, OpenAI’s system automatically routes queries.”

OpenAI's launch post says GPT-5 became the default in ChatGPT, replacing GPT-4o, o3 and o4-mini for signed-in users (E1). It describes GPT-5 as a unified system with a router that sends each query to either a fast model or a reasoning model (E2). An independent report confirms that users no longer had to choose which model to use because queries were routed automatically (E4). However, by 2025-08-13 users could choose Auto, Fast or Thinking modes, and some legacy models had been restored for paid users (E3). The "integrated" design was also a router across several sub-models rather than one model. Both points match the criteria for mostly true rather than true.