Legal Quants Weekly Digest — Week 21

The week the AI-hallucination panic ate Big Law and the Head-of-AI offer landed in the room — Freshfields signs Anthropic, Legora swallows Qura, and one member ships a browser-PII redactor in an afternoon.

• Sullivan & Cromwell hallucinated citations in a live bankruptcy filing — the room treated it as a process-and-education failure rather than an AI failure, and pivoted into a deep technical thread on deterministic per-citation verification pipelines.
• Claude for Word got a wave of independent LinkedIn reviews from members; consensus that vendor moats are mostly prompts and that domain-encoded skills carry more weight than legal-trained models.
• A Head-of-AI offer landed mid-strategy-meeting for a Nordic-biglaw member; the resulting thread was a working masterclass in how to negotiate the role without being silo'd into IT.
• Freshfields signs Anthropic firm-wide; Legora acquires Qura; UK/EU motion increasingly outpacing US biglaw on AI partnerships.
• OpenAI ships an open-source 1.5B PII filter; a member built and shipped a browser-only PII redactor on top of it the same day, running entirely on WebGPU.
• Microsoft Copilot Cowork hands-on — runs Sonnet 4.6 / Opus 4.7 inside M365, OneDrive-only file access, but has the AD/directory hooks Claude Cowork lacks.