dsh-sidebar-branch-chat

In the middle of a long main conversation, you sometimes want to fork off and chase a side question or try an alternate approach, without letting that detour pollute the main transcript. That is the everyday problem Branch Chat tackles. It mounts as a companion tab inside dsh-better-sidebar, with no forking, no second copy, and no modification of the host, requiring only host version 0.11.0 or higher.

The core mechanism is a fresh empty session plus a context-digest injection. The first message you send creates the branch, labelled with the first 20 characters of the text, and every subsequent send continues in that same branch. Instead of copying main-chat events, the branch receives a head-middle-tail sandwich: the first user message, heuristic titles of intervening turns, and the last completed turn with its tool calls and results, all marked reference-only. The branch agent joins the preset generation that the main agent is currently running, sharing the same tool roster and model family; a deployment with no roster stays empty rather than faking tool availability. The session is archived immediately after creation, so the branch vanishes from the main session list and search and lives only in the sidebar tab.

The tab offers branch switching, per-branch model and reasoning-effort selection, an in-flight message queue, and sandbox permission confirmation, all driven by JSON polling (1.5 s idle, 300 ms busy); SSE is not used yet. Keep in mind that the branch reuses the main session working directory and the full write tool set, so file, shell, and git side-effects share the main working tree, and the frame hint is a model-visible soft constraint rather than a permission boundary. Branch Chat is best for DSH users who already run Better Sidebar and want a clean separation between side-path exploration and the main conversation thread.