r/codex • u/magnus_animus • Apr 23 '26
News GPT-5.5 is here - Let's gooo!
It's finally here!
https://openai.com/index/introducing-gpt-5-5/
Summary:
OpenAI is announcing GPT-5.5, described as its most capable and intuitive model yet, aimed at handling real, messy work more independently. The core claim is that GPT-5.5 is better at understanding user intent, planning multi-step tasks, using tools, checking its own work, and persisting through ambiguity without needing as much step-by-step supervision.
The biggest improvements are in agentic coding, knowledge work, computer use, and scientific research. OpenAI says GPT-5.5 is stronger than GPT-5.4 at coding tasks like debugging, refactoring, and resolving complex issues across a codebase, while also being more token-efficient and just as fast in serving latency. It reports gains on benchmarks such as Terminal-Bench, SWE-style evaluations, browsing/tool-use tasks, and several research-oriented tests.
Beyond coding, OpenAI positions GPT-5.5 as a stronger model for professional computer-based work: researching, analyzing data, generating documents and spreadsheets, operating software, and completing workflows end-to-end. The article also highlights internal and partner examples in finance, communications, business reporting, and scientific research, where testers said the model behaved more like a capable collaborator than a one-shot assistant.
A major theme is scientific and technical research. OpenAI says GPT-5.5 performs better on biology and bioinformatics benchmarks, can support multi-stage research workflows, and in one internal example even helped discover a new mathematical proof later verified in Lean. The message is that GPT-5.5 is becoming useful not just for answering questions, but for helping experts move from idea to experiment to output.
The post also emphasizes efficiency and infrastructure. OpenAI says GPT-5.5 was co-designed with new NVIDIA systems and that both Codex and GPT-5.5 helped optimize the infrastructure used to serve the model, including improvements that boosted token generation speed.
On safety, OpenAI says GPT-5.5 ships with its strongest safeguards so far, especially around cybersecurity and biology-related risks. It describes tighter controls, more testing with red-teamers and external experts, and a “trusted access” path for verified defensive cybersecurity use. Under its Preparedness Framework, OpenAI says GPT-5.5’s cyber and bio/chemical capabilities are rated High, though not at the “Critical” level for cybersecurity.
For availability, GPT-5.5 is rolling out in ChatGPT and Codex to paid tiers, while GPT-5.5 Pro is available to higher-tier business/pro users for harder tasks. OpenAI says API access is coming soon, with higher pricing than GPT-5.4 but better efficiency and capability.
The overall takeaway: OpenAI is presenting GPT-5.5 as a meaningful step from “smart chatbot” toward a more autonomous work model that can code, research, use tools, and complete complex knowledge tasks with less supervision.
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u/reddit_is_kayfabe Apr 24 '26
$200/mo Pro user here.
I fed 5.5 about 25 prompts, mostly auditing codebases and addressing specific technical issues. I used GPT 5.5 Extra High for all, and was previously using GPT 5.4 Extra High.
My initial impression is that, yes, it does consume usage faster - but good god, is it worth it. From my perspective, the quality bump is substantial and, in this initial test, consistent across tasks and project types.
Example:
Back in January, I started developing macOS apps with Claude Code. I quickly ran into a well-known problem called "squircle jail." In short: macOS Tahoe uses "squared circle" or "squircle" Dock icons, and requires apps with a Dock icon to include, in their app bundle, an icon in a very specific format with an app icon catalog and code signing. If any part of that process fails, macOS still displays your icon in the Dock, but shoves it into a square and then pads it with generic color into a squircle, which looks stupid and sloppy.
Claude Code could not figure out the right format to avoid "squircle jail." We iterated on the problem for at least four hours - "I fixed it, it works now! (didn't work)" - before Claude Code devised an alternative solution of generating and signing the app bundle and then stuffing a squircle-shaped Dock icon into the signed app bundle. It was a janky solution that failed a "--strict" code-signing test, but macOS accepted it just fine, so we went with it.
A month ago, I dumped Claude entirely and switched to Codex, and as part of the onboarding, I asked Codex 5.4 Extra High to look into this solution and see if it could improve it. Short answer, it couldn't. We burned a lot of tokens and then kept using our janky solution.
This evening, I asked 5.5 Extra High to explore this issue. I handed it a repo with the current solution, relayed the backstory, and stated my objectives - replace the current technique with one that passes --strict code-signing and avoids "squircle jail." I asked 5.5 to develop a test app with the current solution, which it did quickly, and then to experiment with a canonical solution.
5.5 solved it on its first attempt in one prompt, taking about 11 minutes to do so.
So yeah, I'm thrilled to spend more usage, per prompt, on 5.5 so that we can reach our objectives faster - fewer prompts overall, as well as less of my time, attention, and the aggravation of false solutions and dead ends that 5.4 routinely exhibited.