Three frontier releases in a week, and the open-weight gap halved. Moonshot AI published the Kimi K3 weights on 27 July, meeting to the day the end-of-July commitment it made at launch and putting a 2.8-trillion-parameter downloadable model at 57 on the Artificial Analysis Intelligence Index — four points off the top, where the same comparison stood at nine on 23 July. Anthropic released Claude Opus 5 on 24 July at half Claude Fable 5's per-token price and one point above it on the index, a margin Artificial Analysis calls an effective tie while also measuring the new model as slow, verbose, and hallucinating on half of AA-Omniscience. Google shipped Gemini 3.6 Flash (50) and 3.5 Flash-Lite (36) on 21 July plus a restricted security model, but not its 3.5 Pro flagship — and, contrary to the coverage, Flash-Lite is priced above the model it replaces.
The Whole Story
The distance between the best model anyone can download and the best model anyone can buy is now four points. On the independent Artificial Analysis Intelligence Index v4.1, Moonshot's Kimi K3 — whose 2.8-trillion-parameter weights were published on 27 July, the largest open-weight release yet — scores 57, against 61 for Anthropic's Claude Opus 5, which took the top of the index on 24 July by one point over Claude Fable 5, a margin Artificial Analysis itself calls an effective tie. Four days earlier the same comparison stood at nine points. Everything below the leaders is compressed too: GPT-5.6 Sol at 59, GPT-5.5 at 55, Grok 4.5 at 54, Claude Sonnet 5 at 53, GLM-5.2 at 51. The price of any fixed level of capability keeps collapsing (9–900× per year, per Epoch AI), and access remains contested on both sides: June 2026 brought the first model-level US export controls, and Google is holding its new vulnerability-hunting model to governments and trusted partners.
Six years of record show three arcs. Capability: from GPT-3 behind a private-beta API to today's six-lab frontier band. Price: the steepest cost curve in the industry's history — Epoch AI measures inference prices for fixed performance falling 9x to 900x per year, and Stanford's AI Index puts GPT-3.5-equivalent capability at 1/280th of its late-2022 price by late 2024. Access: the pendulum has swung from API-only gatekeeping through the open-weights insurgency (Llama, then DeepSeek, Qwen, GLM) to government-imposed restriction — and, this month, to the largest open-weight release on record.
The open-vs-closed gap is the story's live question, and open weights are not the same as open reach. Kimi K3's licence is close to MIT — no acceptable-use policy, and commercial conditions that bite only above US$20M in revenue or 100M monthly users — but its training data and process are undisclosed, and Rahul Shome of the Australian National University told Nature the model is too large for personal devices and will probably need institutional investment to run. The UK AI Security Institute separately measures the best open-weight model at 4–7 months behind the closed frontier on cyber capability. What is moving down-market is cheap hosted capability, not local capability: Google's $0.30-per-million-token Gemini 3.5 Flash-Lite scores 36 against a class median of 16 and is rolling out inside Google Search.