VS Code 1.135 picks up agent sessions that were started in another application

The 26 August VS Code release adds External Agent Sessions — a Copilot or Claude agent session begun somewhere else can be continued inside the editor. Agent Host now runs the agent harness in its own process so several VS Code windows can attach to one session, the Agents view collapses to a single pane with session pills showing changes, pull requests and artifacts, an experimental /rubber-duck command asks a second, complementary model to look for missed edge cases, and hovering a chat response shows the input, cached-input and output token counts for that turn.

What it means A session that survives leaving the tool it started in is the first real answer to agent work being trapped per-application, and the per-turn token breakdown is the first place a team can see what a long run actually cost.