Start a fresh thread from a summary to keep long sessions focused

Why it matters

Long debugging or refactoring sessions in Zed can hit the model context limit, and automatic compaction is not confirmed as shipped (issue #35019 (opens external site) ↗). The built-in "Start new thread from summary" command gives you a manual handoff that keeps the work focused without starting from zero.

Steps

1. Pick a natural checkpoint, such as a finished bug fix or a completed refactor step, before the session gets bloated.
2. Ask the agent for a summary covering the goal, files changed, decisions made, open questions, and the next concrete action.
3. Save that summary outside the chat, for example in TODO.md or ROADMAP.md in the project. Compacting finished roadmap sections by hand is a pattern reported in issue #35019 (opens external site) ↗.
4. Run the built-in "Start new thread from summary" command in Zed. Its underlying action is agent::NewNativeAgentThreadFromSummary.
5. In the new thread, point the agent at the saved summary file so it starts from the recorded state rather than from memory.
6. Keep the old session for reference, work only in the new one, and repeat the checkpoint when the context grows again.

Common mistakes

• Starting a new session without a written summary, which drops the decisions already made.
• Letting the summary drift from the code. Re-check it against the repo before you hand off.
• Carrying every old detail forward. Keep the summary to the goal, current state, and next step.
• Assuming compaction will happen automatically. The related pull requests were closed or stalled (issue #35019 (opens external site) ↗), and one user reported that binding this action to a key failed because it requires an INPUT argument, so plan on the mouse for now.