Claude Opus 5.5, the #1-ranked model
Claude Opus 5.5 is Anthropic’s most capable model and, in September 2026, the highest-ranked model on the Artificial Analysis Intelligence Index. SelGPT includes it in Plus.
By the SelGPT team. Updated
Claude Opus 5.5 is Anthropic’s most capable AI model. In September 2026 it scored 58 on the Artificial Analysis Intelligence Index, the highest of any model tested. SelGPT includes it in Plus from $9.99 a month billed yearly, alongside GPT-6.1, Gemini and Kimi.
Why Claude Opus 5.5
It scored 58 on the Artificial Analysis Intelligence Index in September 2026, the highest of any model tested. Use it for work that has to be right the first time.
What it is good at
- Contracts, reports and other documents where a missed detail is costly.
- Hard coding problems, architecture decisions and code review.
- Careful writing: proposals, applications and anything you publish.
Plans
About 80 messages a month on Plus, 400 on Pro 5× and 1,250 on Pro 15×. It draws from your plan’s monthly allowance, shown as a percentage in the app. GPT-6 Luna stays unlimited on paid plans when the allowance runs out. See SelGPT pricing.
Questions
Is Claude Opus 5.5 the best AI model?
In September 2026 it ranked #1 on the Artificial Analysis Intelligence Index with a score of 58. Rankings change, so check the leaderboard for the latest.
How many Claude Opus 5.5 messages do I get in SelGPT?
About 80 a month on Plus, 400 on Pro 5× and 1,250 on Pro 15×.
Related
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- ModelsEvery model in SelGPT: GPT-6 Luna, Claude Opus 5.5, GPT-6.1 Sol, Gemini 3.8 Flash, Kimi K3, DeepSeek, MiMo, GLM and Qwen, in one chat.
- GPT-6 LunaUse OpenAI’s GPT-6 Luna in SelGPT for everyday questions, writing, files and images, unlimited within fair use on every paid plan.
- GPT-6.1 SolUse OpenAI’s GPT-6.1 Sol in SelGPT for writing, analysis and code, alongside Claude, Gemini and Kimi, from $9.99 a month billed yearly.
- Gemini 3.8 FlashUse Google’s Gemini 3.8 Flash in SelGPT for research and long documents, alongside GPT-6.1, Claude and Kimi, from $9.99 a month billed yearly.