Claude Opus 4.7 has claimed the #1 spot in the June 2026 AI developer tool power rankings, holding the top WebDev Arena score at 1567 Elo (with thinking) and 1562 Elo without. Five new frontier models entered this month — and none displaced it.
New Entrant: GPT-5.5
OpenAI’s GPT-5.5 enters the rankings as the company’s first fully retrained base model since GPT-4.5. It leads Terminal-Bench 2.0 with an impressive 82.7% score and delivers 52.5% fewer hallucinations than its predecessor. Currently available only through ChatGPT subscription tiers and Codex — no public API pricing yet.
GPT-4.5 Retirement Confirmed
OpenAI has confirmed GPT-4.5 retires on June 27, 2026, after a 30-day sunset period. It will be fully replaced by GPT-5.3 across the API.
June 2026 AI Model Rankings Snapshot
- 🥇 Claude Opus 4.7 — #1, WebDev Arena leader, best-in-class MCP-Atlas (77.3%)
- 🥈 GPT-5.5 — New entry, Terminal-Bench 2.0 leader at 82.7%
- 🥉 Gemini 3.1 Ultra — 2M token context, native multimodal
- NVIDIA Nemotron 3 Ultra — 550B parameters, best US open-weights model
Reasoning Is Now the Default
A key trend in June 2026: GPT-5.4 Thinking, Claude Opus 4.7 with adaptive thinking, and Gemini 3.1 Pro all blend reasoning directly into the main model — the separate “o-series” branding from OpenAI is gone. Reasoning is no longer a premium add-on; it’s the standard.