Pondero Brief: Copilot's sandbox goes GA as Harvard finds review erases agent gains

        October 12, 2026

Pondero Brief: Copilot's sandbox goes GA as Harvard finds review erases agent gains

Pondero Brief - OCTOBER 12TH, 2026

      Plus Haiku 5.5 in Copilot, an offline Gemma embedder, and RTX Spark's real GPU memory.

pondero.

                      BRIEF · OCT 12

Copilot's sandbox is GA, which means admins can now mandate it.

                  GitHub's October changelog bundles local sandboxing GA with a new model and local-model discovery.

Per GitHub's changelog, local sandboxing is GA across Copilot CLI, the app, and VS Code, with Haiku 5.5 and local Ollama models joining the picker.
See what the sandbox blocks and how admins enforce it, or check which Copilot plans include Haiku 5.5.

                        Also in today's brief

An open embedder small enough for your phone

Code review might be eating your AI gains

RTX Spark's memory math doesn't add up

A model that grades and retrains itself

      Models & Releases

          Google's new open embedder indexes video on a phone.

Per Google's blog, EmbeddingGemma 2 packs five media types into one open 740M-parameter model under Apache 2.0. See the on-device RAM numbers.

          Sakana's model grades its own homework, and the grades hold up.

Self-grading and retraining lifted one model's win rate from 53.9% to 69.9% in two rounds, per Sakana AI. See the one task type where it got worse.

      Tools & How-To

          Coding agents write more code, and reviewers eat the gain.

Agents lift code output 30 percent but stretch review time 49 percent, per Harvard researchers using Jellyfish data. See why more agent seats did not ship more features.

          RTX Spark's top laptop gives the GPU less memory than the box says.

The 128GB SKU exposes only about 110GB to the GPU after Windows takes its share, per Microsoft engineers. Do the memory math before you preorder.

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Jonathan Hildebrandt

                      Co-founder and primary operator of Pondero. Writes the Pondero Brief.

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