GPT-5.5 may not be in the official OpenAI API… but it's available via the apparently approved-of Codex API backdoor So I used that to make these pelicans (default and xhigh)! https://
simonwillison.net/2026/Apr/23/gp
t-5-5/
…
LLMS
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GPT-5.5 Available via Codex API Backdoor for Image Generation
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GPT-5.5 Builds Playable Three.js Game in One Shot
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This is the game GPT-5.5 built for me in one shot, featured on the release page.
— Pietro Schirano (@skirano) 23 avril 2026
What makes it different from previous AI-generated games is how fun it actually feels to play.
The controls are smooth, and every shape is generated from scratch in Three.js. pic.twitter.com/dMQE2JbZvzThis is the game GPT-5.5 built for me in one shot, featured on the release page. What makes it different from previous AI-generated games is how fun it actually feels to play. The controls are smooth, and every shape is generated from scratch in Three.js.
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CPUs Critical Infrastructure for Agentic AI Performance
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🔥 Hot take: CPUs don’t get enough credit in agentic AI.
— SambaNova (@SambaNovaAI) 23 avril 2026
They prep data, route requests, and coordinate with accelerators, while also handling everything outside the model like code execution, DB queries, and validation.
Without them, inference can’t keep up 🦾
Do you agree… pic.twitter.com/RzBjFUHACdHot take: CPUs don’t get enough credit in agentic AI. They prep data, route requests, and coordinate with accelerators, while also handling everything outside the model like code execution, DB queries, and validation. Without them, inference can’t keep up Do you agree
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Anthropic Mythos vs GPT-5.5 CyberGym Benchmark Scores Compared
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Also, a detail some of you may have missed: Anthropic’s gated Mythos model scored 83% on CyberGym. OpenAI just dropped GPT-5.5 at 82%. Except GPT-5.5 is actually available for people to use.
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AI Models Automate Self-Jailbreaking Process Advancement
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I mentioned this project in this week's AI Lab newsletter. It suggests a kind of flip side to the idea of self-improvement in AI models. As models become more powerful, it shows they can automate the process of figuring out how to jailbreak themselves and other models remarkably
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GPT-5.5 performance on ARC-AGI-2 benchmark
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GPT-5.5 just hit 85% on ARC-AGI-2. Somewhere, Yann LeCun is explaining why this still doesn't count. LLMs keep climbing a tall tree toward the moon
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New Model Uses Fewer Tokens While Maintaining Intelligence
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it quite literally uses much less tokens when compared to 5.4 – use it for awhile on some tasks and you'll see it doesn't have as big of difference on usage compared to the intelligence you get access too
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NVIDIA Advances Codex and GPT-5.5 Development at HQ
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Codex + GPT-5.5 is moving fast here at NVIDIA HQ.
— NVIDIA AI (@NVIDIAAI) 23 avril 2026
We’ve even got our own Codex Lab for NVIDIANs to get started. https://t.co/PTqytJWp0f pic.twitter.com/zWnSnKfansCodex + GPT-5.5 is moving fast here at NVIDIA HQ. We’ve even got our own Codex Lab for NVIDIANs to get started.
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Chime’s Jade AI Co-Pilot Heads to LangChain Interrupt Conference
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@Chime is heading to Interrupt. Jade is an AI co-pilot that provides financial education to Chime customers, helping users understand their finances and invest in their future. At Interrupt, the Agent Conference by LangChain, Engineering Lead Philipp Comans will share how
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Claude 5.5 Outperforms Opus Beyond Frontend Work Analysis
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Having used both extensively, this doesn’t track with my experience. Aside from frontend work, 5.5 is leaps and bounds ahead of Opus. I don’t think this benchmark tells us anything useful anymore.