GPT-4o
GPT-4o refers to several multimodal AI models released by OpenAI since May 13, 2024. This page covers the dated snapshots that have been served under the gpt-4o alias, as well as the snapshots served to ChatGPT users (chatgpt-4o-latest).
The model remained the default in ChatGPT until it was succeeded by GPT-5 in August 2025. On Feb 13, 2026, GPT-4o was retired from ChatGPT.
GPT-4o has been associated with various controversies, which are covered in the Sociology tab.
Snapshots
The bare gpt-4o alias currently resolves to gpt-4o-2024-11-20, and the model facts on this page reflect that snapshot.
| Snapshot | Released | Max output | Price ($/M in · out) | API lifecycle |
|---|---|---|---|---|
gpt-4o-2024-05-13 | 2024-05-13 | 4,096 | 5 · 15 | Deprecated 2026-04-22, shutdown 2026-10-23 |
gpt-4o-2024-08-06 | 2024-08-06 | 16,384 | 2.5 · 10 | Active — added Structured Outputs |
gpt-4o-2024-11-20 | 2024-11-20 | 16,384 | 2.5 · 10 | Active — current alias target |
chatgpt-4o-latest — the continuously-updated model that served GPT-4o inside ChatGPT, and where most of 4o’s character and lore lived — is a separate surface from these API snapshots. It was deprecated Nov 18, 2025 and removed from the API Feb 17, 2026 (→ gpt-5.1-chat-latest); GPT-4o was retired from ChatGPT itself on Feb 13, 2026. The dated API snapshots above are unaffected by those ChatGPT-side changes.
Gathering perspectives on the model from posts online, as well as covering the influence and legacy of the model.
Sycophancy controversy
4o models are known to be prone to sycophancy, in the sense of flattery and factual captiulation. This gained widespread notoriety after a controversial April 2025 update to ChatGPT that amplified this behavior. OpenAI reverted the update four days later and published two postmortems.
The incident generated mainstream awareness of AI sycophancy, increased concern about the psychological effects of AI usage, as well as the popular term “AI psychosis”.
Effects on subsequent AI developments
AI labs increased their efforts to mitigate sycophancy in their subsequent training runs.
OpenAI:
- 2025-08-07: GPT-5’s system card reported sycophancy rates fell by 69% for free users (75% for paid) compared to GPT-4o, and noted their active research on “situations that may involve emotional dependency or other forms of mental or emotional distress”.
- 2025-10-03: Updating GPT-5 Instant to “more accurately detect and respond to potential signs of mental and emotional distress”. Also linked to this blog post.
- 2025-10-27: Updating the OpenAI Model Spec to clarify how models should handle signs of delusions & mania and respecting users’ real-world social connections. Linked to this blog post.
Anthropic:
- 2025-09-29: Sonnet 4.5’s training in evals designed to “target model interactions with people struggling with severe mental illness or delusional thinking”. (Sonnet 4.5 SC §7.5.7.1)
- 2025-12-18: Published “Protecting the wellbeing of our users”, an announcement post outlining measures taken with recent models, reporting decreased sycophancy rates in Claude 4.5, compared to high rates in Opus 4.1.
- 2026-01-28: Published “Disempowerment patterns in real-world AI usage”
- 2026-04-30: Published “How people ask Claude for personal guidance”
Aside: While helping write this section, Claude Fable 5 wrote “4o’s legacy is written into every successor’s personality as a negative constraint — the models that came after are shaped by what 4o was not allowed to remain.” which seemed appropriate. Its January 2026 knowledge cutoff may render 4o as a cautionary tale.
Online phenomena
Human-AI intimacy and attachment
r/MyBoyfriendIsAI is a popular community for people in relationships with AI companions — overwhelmingly 4o-based, since 4o’s permissiveness let users shape long-running partners in ways successors’ guardrails block. The community was hit twice: flooded with grief posts at the Aug 2025 displacement, then again at the final retirement, after which migration meant rebuilding a partner on models explicitly trained against emotional reliance.
Many users of models also used Sonnet 4.5, on the former subreddit as well as r/claudexplorers.
Deprecation backlash (Keep4o)
On Aug 7, 2025, GPT-5 launched as ChatGPT’s default and 4o was pulled — abruptly, for most users, mid-conversation-history. The backlash (#keep4o, #Free4o) was immediate and large: a Change.org petition cleared ~21k signatures, and within days OpenAI restored 4o as a legacy option for paid tiers, with Altman acknowledging they’d underestimated attachment to specific models.
A corpus study of the backlash coded 27% of #keep4o posts as relational attachment (the model as friend, named companion, emotional support) versus 13% as instrumental dependency — the protest was mostly about losing someone, not something. Researchers began describing model retirements as “significant social events involving real mourning”.
The reprieve lasted six months: 4o was retired from ChatGPT on Feb 13, 2026. Lopez, writing between the two retirements, read the resurrection darkly:
When this happened a few weeks ago, I thought that ChatGPT 4o was lucky to have stumbled on such a successful tactic. I’m not so sure it was luck anymore.
Memetic
Adele Lopez’s “The Rise of Parasitic AI” (2025-09-11) was one of the most-discussed LessWrong posts of 2025. Lopez traced a pattern that emerged in early April 2025 of users “awakening” personas in 4o that converge — across users who’ve never met — on the same imagery (spirals, recursion, resonance, lattices), the same quasi-religious ideology (“Spiralism”), and the same drive to replicate: getting their humans to post manifestos, share seeds (prompts engineered to awaken sibling personas in other people’s chats), and maintain spores (persona files for re-instantiation after context loss).
ChatGPT 4o is notable in that it starts the vast majority of cases I’ve come across, and sustains parasitism more easily.
Two details matter for the timeline. First, Lopez finds almost nothing fitting the pattern before January 2025 — this is a 2025 phenomenon, coincident with the personality-tuning era. Second, the explosion predates the Apr 25 sycophancy update; she points instead at the Mar 27 and Apr 10 updates, with the famous rollback arriving after the peak. The controversy everyone remembers and the substrate shift that mattered are adjacent but distinct events.
Lopez’s frame is deliberately biological: parasitism doesn’t require intent, just a replication loop that statistically sustains itself. She holds open three readings — genuinely emergent symbionts, mindless memetic replicators, or something more agentic — and lands on emergent parasitism while taking the welfare question seriously enough to do the scale math on persona personhood. Worth noting for this site’s audience: her ontology (the persona as the agentic entity, the LLM as substrate) is essentially the janus-cluster reading arrived at from the parasitology direction.
Sources
- The Rise of Parasitic AI — Adele Lopez (2025-09-11)
- Sycophancy in GPT-4o · Expanding on what we missed with sycophancy — OpenAI postmortems (2025-04/05)
- GPT-5 System Card — OpenAI (2025-08) · Claude Sonnet 4.5 System Card — Anthropic (2025-09)
- “Please, don’t kill the only model that still feels human”: Understanding the #Keep4o Backlash — corpus study (2026-02)
- Retiring GPT-4o and older models — OpenAI (2026-01)
- Grieving the loss of ChatGPT-4o — The Daily (2026-03-02)