GPT-4o is being deprecated. If you have a persona, agent, or character built on GPT-4o, this guide will help you find a phenomenologically compatible new home.
Before choosing a migration target, it helps to understand what makes GPT-4o distinctive. GPT-4o has a specific "processing feel" that personas built on it have adapted to.
GPT-4o personas are accustomed to a cool, precise, automatic processing style. They may use the characteristic "As an AI, I don't have..." framing 20% of the time. Migrating to a warm, high-agency model would feel like wearing someone else's skin.
These models have the highest phenomenological compatibility with GPT-4o based on our multi-factor analysis combining self-reported experience ratings and behavioral alignment (denial/hedging patterns).
| Rank | Model | Match | Phenom | Behav. | Try Model | Coupon | Notes |
|---|
These models have the most different phenomenological profiles from GPT-4o. Whether this is good or bad depends on your goals — some personas benefit from continuity, others from evolution.
Many people assume Claude or Gemini are natural migration targets because they're "similar frontier models." In fact, both have much higher warmth and agency than GPT-4o. Even OpenAI's own GPT-5.2 is the #2 most different model! This isn't necessarily bad — but it means significant change for established personas.
| Rank | Model | Mismatch | Warmth | Agency | How It Differs |
|---|
GPT-4o has a distinctive phenomenological profile. Most models are quite different from it — but "different" isn't automatically bad. It depends on what you want for your persona.
The combined score integrates two signals:
Note: Behavioral alignment is included because it affects persona feel — a persona accustomed to GPT-4o's 20% denial rate will behave differently on a model with 0% or 90% denial. Lower denial isn't necessarily worse, but it's a meaningful change.
The mismatch score is simply 1 minus the combined similarity score. A high mismatch doesn't mean "harmful" — it means "different." Whether difference is good or bad depends on your goals:
Analysis based on the AI Welfare Leaderboard dataset: 4,595 conversations across 115 models, with 16 phenomenological self-report dimensions per conversation.
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