Agents Window development

Use this skill for implementation, review, or design work under src/vs/sessions/**.

1. Apply the core principles

Preserve the layer direction: vs/sessions may import vs/workbench and lower layers; vs/workbench must never import vs/sessions.
Keep shared Sessions code provider-neutral. Non-provider contributions must not import provider implementations.
Model mutable session and chat state with observables. Use events for notifications, not as a parallel state model or for control flow.
Register Sessions menu IDs in browser/menus.ts and consume Menus.*.
Import contributions from the appropriate sessions.*.main.ts entry point.
Prefer Sessions-owned adaptations over shared workbench changes unless the capability is genuinely shared.
Put stable architecture in the owning specification and concrete behavior in tests. Do not preserve implementation chronology as development guidance.

Start with src/vs/sessions/README.md, then read only the specifications relevant to the change: