Stitch

Taking Reinforcement Learning Cross Datacenter — Nan Jiang, Modal

Aug 10, 2026 · 19:50

Nan Jiang from Modal explains how reinforcement learning post-training can run across datacenters by shipping sparse weight deltas instead of full checkpoints. He argues that less than 1% of rollout-visible weights change between versions because Adam steps are tiny relative to BF16 rounding boundaries, a mechanism he calls Adam absorption. Modal's implementation, Stitch, lets rollout engines sync via patches (e.g., 500 MB instead of 500 GB) and operate as an elastic fleet across regions and providers. He cites internal runs showing 0.15% weight changes initially, settling near 0.05% for GLM 4.7 Air in FP8, and notes gradients are dense but updates small. He also explores whether sparsity holds for Muon and async RL scalability.

Proactive Agents – Kath Korevec, Google Labs

Dec 13, 2025 · 16:51

Kath Korevec, Director of Product at Google Labs, argues that AI coding agents must become proactive rather than reactive to truly reduce developer cognitive load. She introduces Jools, a proactive autonomous coding agent that observes workflows, personalizes responses, and intervenes at the right moment. Korevec details three levels of proactivity: level one auto-fixes issues during tasks; level two learns project context; level three connects agents across code, design, and data. She highlights features like memory, a critic agent for code quality, verification via Playwright, and a to-do bot. A demo shows Jools indexing a codebase and suggesting high-confidence tasks. Korevec ties this to her personal Halloween animatronic project, where she wished Jools handled debugging so she could focus on creative LED animations.