New AI model releases are outrunning their own training data
Ten of the 20 current AI models listed by the freshness tracker stale.jock.pl carry a training cutoff their lab actually publishes. Several of them launched months behind the date on their own release announcement.

The site went up on Hacker News on 16 September. It tracks two dates per model: the day the lab shipped it and the day it stopped reading. It lists 20 models across 8 labs, and the browser counts upward from each date live.
The gap is the story. OpenAI released GPT-6 Astra on 3 September 2026, and its training cutoff is 30 April 2026. Its sibling GPT-6 Sol shipped on 22 September with a cutoff of 20 April, and GPT-6 Luna arrived the same day with a cutoff of 18 May. Anthropic's Claude Opus 5.5, released 22 September, stops at June 2026. Claude Sonnet 5 came out on 30 June and stopped reading in January.
For half the list, the answer is unknown. Mistral AI's Large 3, Small 4 and Medium 3.5, Alibaba's Qwen3.8-Max and Qwen3.8-Flash, Meta's Muse Glimmer and Muse Spark 1.3, DeepSeek's V4-Pro and V4.1-Flash, and Google DeepMind's Gemini 3.8 Flash all show no established cutoff. The page is careful about what that means. A blank is what the checked vendor sources failed to establish, not proof the lab never published one.
Why the date matters more than the version number
The site's own framing is blunt. A model can ship in September and still stop reading in April. That leaves it five months behind on launch day, before anyone types a prompt into it.
Search tools do not fix that, according to the page. When a model searches, it reads a few pages, uses them in one answer and forgets. Open a new chat and the cutoff is back. The trigger decision also runs on the same weights that hold the stale fact, so misses land where the model is most confident. The page says it measured this over 2,000 calls across 16 models, each given a web search tool. Frontier models decided correctly almost every time. Weaker ones stated settled facts that had changed and searched the web for the boiling point of water.
I gave 16 AI models a search button and asked who the king of Norway is. Five named a dead man.
That is the site's own line, and it is the cleanest illustration of the problem. A model that does not know a monarch has died will not reliably decide to check.
The workaround is aimed at agents, not people
The page publishes the same data as models.json, with release date, published cutoff and a source link per model. It suggests pasting a short instruction block into an AGENTS.md or CLAUDE.md file so an agent fetches it before naming any model as current.
On the lab side, the published cutoffs are uneven. Five of the eight labs, Anthropic, Google DeepMind, Meta, OpenAI and xAI, have a published cutoff for at least one model in the list. Ten of the 20 models carry one. The rest do not.
The page also offers a crude self-test: ask the model for its own training cutoff. One that answers, or admits uncertainty, is behaving. One that invents a confident date has told you something. The site's warning is that a model is a poor source on models, so check the answer against the table rather than trusting it.
Sources
1All figures and quotations in this text come from the sources listed below.
Content prepared by the editorial team with AI assistance.
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