This week in AI: 31 Aug 2026 to 6 Sep 2026

9 stories this week across 7 categories. Each links to the official announcement, filing or paper it is based on.

Illustration of curved dashed grid lines on a green background beside a protractor on graph paper. — Anthropic says Claude agents formalized Fermat's Last Theorem in Lean in 11 days

AI Research4 Sep 2026, 09:00 UTC

Anthropic said on 4 September 2026 that Claude agents produced a complete Lean proof of Fermat's Last Theorem in 11 days: 13 million lines checked by Lean.

Summary

Anthropic reported on 4 September 2026 that dozens of Claude agents produced the first complete, computer-checked proof of Fermat's Last Theorem in the Lean proof assistant in 11 days, largely autonomously. The proof runs to 13 million lines of Lean, more than five times the size of Mathlib, and uses only Lean's standard axioms. Kevin Buzzard of Imperial College London, who leads the community formalization project, reviewed it.

Close-up of a brown fruit fly with red eyes and translucent wings standing on a pale surface. — Google Research and Janelia map the male fruit fly nervous system with 166,000 neurons

AI Research3 Sep 2026, 16:00 UTC

Google Research and HHMI Janelia published the full male fruit fly central nervous system on 3 September 2026: over 166,000 neurons and 125 million synapses.

Summary

Google Research and HHMI Janelia published a complete map of the male fruit fly's brain and nerve cord on 3 September 2026, described in a paper in Cell. The connectome contains more than 166,000 neurons and 125 million synaptic connections, the largest brain map by neuron count to date, according to the authors. AI tools traced the neurons from electron microscope images and Janelia experts proofread the result. The data is open to download.

A brick and glass office building with snow on the hedges and walkway in front, under a clear sky. — Microsoft finds phishers reusing the ASCII smuggling prompt injection trick at scale

Cybersecurity3 Sep 2026, 16:00 UTC

Microsoft said on 3 September 2026 that phishers used invisible Unicode tag characters, a prompt injection trick, to split lure words and dodge filters.

Summary

Microsoft researchers reported on 3 September 2026 that a finance-themed phishing campaign borrowed ASCII smuggling, a technique known from AI prompt injection research. Instead of hiding instructions for a model, the sender put invisible Unicode tag characters inside words such as funding to break keyword and classifier matches. Hits on Microsoft's signature jumped from about 21,000 to over 1.3 million on 9 February 2026 and peaked above 2.3 million messages on 11 February.

In brief

Anthropic says Claude agents formalized Fermat's Last Theorem in Lean in 11 days Anthropic said on 4 September 2026 that Claude agents produced a complete Lean proof of Fermat's Last Theorem in 11 days: 13 million lines checked by Lean.
Google Research and Janelia map the male fruit fly nervous system with 166,000 neurons Google Research and HHMI Janelia published the full male fruit fly central nervous system on 3 September 2026: over 166,000 neurons and 125 million synapses.
Microsoft finds phishers reusing the ASCII smuggling prompt injection trick at scale Microsoft said on 3 September 2026 that phishers used invisible Unicode tag characters, a prompt injection trick, to split lure words and dodge filters.
Figure signs Nscale deal for up to 100,000 Vera Rubin GPUs to train Helix Figure said on 3 September 2026 that Nscale will deploy up to 100,000 NVIDIA Vera Rubin GPUs for it, with a $3.5 billion initial compute commitment.
OpenAI releases GPT-6 Astra at $10 per 1M input tokens, its first Critical-rated cyber model OpenAI released GPT-6 Astra on 3 September 2026 with a 1,050,000-token context, $10 input and $50 output per 1M tokens, and a Critical cybersecurity rating.
Broadcom reports $16.7B AI chip revenue, up 221%, in a $29.6B fiscal third quarter Broadcom reported $29.6B of revenue for its fiscal third quarter of 2026, with AI semiconductor revenue up 221% to $16.7B, and guided to $21.7B of AI revenue.
CrowdStrike launches Falcon Guardian to find and police AI agents on company endpoints CrowdStrike introduced Falcon Guardian on 1 September 2026, an AI detection and response product that inventories AI agents and blocks unapproved ones.
US Justice Department backs OpenAI, says training LLMs on copyrighted text is fair use The US Justice Department told the court on 1 September 2026 that training LLMs on copyrighted text is fair use, in the OpenAI copyright litigation.
Waymo opens robotaxi rides in Denver, San Diego and Tampa, reaching 14 cities Waymo said on 1 September 2026 that it is welcoming its first public riders in Denver, San Diego and Tampa, bringing its fully autonomous service to 14 cities.