dsh-fork-diff

When you fork a session in DeepSeek Harness, the real question is rarely about which branches exist; it is about what exactly differs between the two public histories. Opening each session and scrolling back and forth makes it hard to compare long answers, tool-call trajectories, and token costs at a glance. dsh-fork-diff collapses all of that into a single filterable two-pane view.

Under the hood, the plugin auto-discovers parent, child, and sibling branches, then aligns user messages, final assistant answers, tool calls, and tool results segment by segment. Line-level highlighting distinguishes unchanged, modified, left-only, and right-only content, while summaries cover elapsed time and visible token usage. Large histories explicitly enter a fast-alignment mode rather than claiming approximate results are exact. Everything is strictly read-only: no forks are created, no session events are written, and no conversation content is uploaded.

Built for Agent experimenters who frequently fork branches to A/B compare runs: after a multi-path conversation, click the Compare Branch button, pick a counterpart, switch to Diff-only mode, and pinpoint the divergence in seconds before deciding which path to keep.