June 2026 gave us three new frontier models in the span of two weeks: Anthropic’s Claude Fable 5, OpenAI’s GPT-5.5 inside ChatGPT, and Google’s Gemini 3.1 Ultra in Gemini. If you only pay for one, the honest answer to “which is best” is “it depends on the job” , but the differences are sharper this generation than they’ve been in a while. Here’s how they actually compare.
The 30-second verdict
- Best for coding & long, hard tasks: Claude Fable 5.
- Best all-rounder for everyday use: GPT-5.5 in ChatGPT.
- Best for huge documents & mixed media: Gemini 3.1 Ultra.
If you want the reasoning behind those calls, read on.
Coding and complex work
This is where the gap is widest. Claude Fable 5 scores 80.3% on SWE-Bench Pro, a benchmark that measures resolving real software issues , versus 58.6% for GPT-5.5 and 69.2% for Anthropic’s own previous flagship, Opus 4.8. Anthropic says the lead widensas tasks get longer and more complicated, which matches what we see in practice: Fable 5 is the one we reach for when a job has many steps and can’t tolerate the model losing the thread halfway through.
GPT-5.5 is no slouch , it’s OpenAI’s smartest model yet and noticeably better at coding than GPT-5.2 , but on the hardest engineering work it currently trails. Gemini 3.1 closes some of the gap with its new sandboxed code-execution tool, which lets it write, run, and test code mid-conversation rather than just suggesting it.
Context length and multimodality
Gemini 3.1 Ultra wins this category outright with a 2-million-token context window that works natively across text, images, audio, and video. If your work means dropping in an entire codebase, a book-length PDF, or a video file and asking questions about it, nothing else is close. Its improved grounding is also aimed squarely at reducing hallucinations on factual queries.
Claude Fable 5 is strong on long-context too , it’s one of its headline improvements , and excels at vision. GPT-5.5 is capable across modalities but isn’t trying to win the raw-context race.
Everyday use, writing, and feel
For the “help me write this email, explain this, plan my week” work that most people actually do, GPT-5.5 Instant is the most polished default. OpenAI retuned it to sound more natural, pace its answers better for practical help, and lean less on the long, bullet-heavy formatting earlier models defaulted to , with fewer hallucinations and better personalization controls.
Claude has long been the favorite for nuanced writing and careful reasoning, and Fable 5 continues that. Gemini is the most tightly integrated with Google’s ecosystem (Search, Workspace, Android), so if you live in those tools it has a convenience edge regardless of raw benchmarks.
Availability and pricing notes
A few practical things to know in 2026:
- OpenAI retired GPT-5.2 from ChatGPT (June 12) and is sunsetting GPT-4.5 on June 27 , existing chats roll forward to GPT-5.5 automatically. ChatGPT Pro also dropped from $200 to $120/month.
- Anthropicships Fable 5 as its top generally-available model, with an even more capable, restricted “Mythos 5” tier limited to vetted partners.
- Google made Gemini 3.1 Ultra widely available alongside its Imagen 3 image models.
So which should you pay for?
Pick by your dominant use case:
- You write or ship code, or run long multi-step jobs → Claude.
- You want one reliable everyday assistantwith the smoothest UX → ChatGPT.
- You work with massive documents or mixed media, or live in Google’s tools → Gemini.
For most teams the right answer is one paid seat of your primary model plus the generous free tier of a second for sanity-checking. The meaningful differences now are about fit, not raw capability , all three are excellent.
Want the side-by-side on specific tools rather than models? See our best AI tools of 2026 rankings, or compare any two head-to-head on the comparison pages.
Tests AI tools against real work and writes the verdicts on AIisMagic. No paid placements.