robiteame/dsh-session-tree-extension

Append-only, multi-branch conversation trees for DeepSeek-Harness — fork any historical node, clone a branch into a new session, and browse the whole lineage as one merged WebUI graph. Old history is never edited or deleted.

Three commands:

Command	What it does
/tree	Open the merged lineage graph: every non-subagent session and node, clickable and bindable
/fork	Branch from any historical node — the fork appears in the graph and as an inline menu under its source session
/clone	Duplicate the current conversation into an independent new session under the same project

Screenshots

Tree panel (light and dark) with the sidebar's inline fork-branch menu:

The inline /fork branch menu beneath its source session:

Published as four npm packages under the @robiteame scope:

Package	Role
@robiteame/dsh-session-tree	Carrier Bundle: one install mounts everything below through its composition layer
@robiteame/dsh-pi-agent-session-tree	Host domain service: the SessionTree/SessionTreeStore domain model and the sessionTree Remote
@robiteame/dsh-tool-session-tree	Command surface: the /tree /fork /clone commands
@robiteame/dsh-client-ui-session-tree	WebUI tree panel: a native tab in the Harness 0.2 right Sidebar, with an additive overlay fallback for older stock builds

Install (users)

DeepSeek Harness Desktop

Open Settings → Plugins → Market, search for @robiteame/dsh-session-tree, install it, and restart the desktop app. The desktop plugin manager activates the carrier bundle, so the next boot composes the three rows (pi-agent-session-tree, tool-session-tree, ui-session-tree) that load the Host service, the commands, and the browser panel.

The desktop app currently bundles the 0.2.1-rc.2 CLI, whose dsh plugin command only forwards to pnpm and does not activate a newly installed bundle. Use the in-app market there; after the restart, /tree opens the panel.

CLI (0.2.1-rc.3 and newer)

On a CLI that ships the 0.2.1-rc.3 plugin manager, one command installs and activates the bundle:

dsh plugin --profile <profile> add @robiteame/dsh-session-tree

Prebuilt tarballs install the same way and need no build scripts:

dsh plugin --profile <profile> add robiteame-dsh-session-tree-0.7.0.tgz

After installing, restart the profile. Verify the composed layer:

dsh --profile <profile> --dump-config   # should list the three session-tree rows

Requires DeepSeek-Harness 0.2.1-rc.2 through 0.2.1-rc.3 (the latest published next is 0.2.1-rc.3; the current desktop build is 0.2.1-rc.2) and Cordis ~4.0.5; the target installation provides those peers. No install scripts run — the tarballs ship prebuilt lib/ artifacts.

The three commands

/tree — open the tree panel

/tree opens the right-side panel as one merged graph for the current session's lineage: ancestors, forks, and clones appear in a single git-style view, with user messages, assistant replies, tool calls, and model switches shown as connected nodes. Shared copied prefixes are deduplicated, fork points carry session badges, and the current session's path stays highlighted. Click a node to bind it; clicking a node owned by another session opens that session first. Collapse individual subtrees or whole session branches to focus the graph.

/fork — branch from any historical node

/fork picks an earlier user prompt and grows a new branch from there: the conversation continues along the new path while the original one stays intact. The fork is created through the official native fork API, so it appears in the session list with real parent linkage. The plugin adds the new branch to the merged graph and also renders it as an inline collapsible menu directly beneath its source session's row. Both views follow the official reactive session list, so new branches appear without a refresh.

/clone — duplicate into a new session

/clone copies the current conversation — through its root path — into an independent Session under the same project. The source history stays read-only; the clone is yours to continue separately.

Branch switching and graceful degradation

The plugin never modifies Harness core files. It capability-detects the optional branch-selection engine API at runtime:

• Native mode — on a checkout carrying dev/session-branch-surface.patch (Session.selectMessageSurface()), jump/fork switch the model-visible history directly: the next turn genuinely starts from the new branch.
• Stock mode — on an unmodified official Harness, the plugin emulates the switch through official append APIs (an empty replace surface event) plus a plugin-owned sidecar under $DSH_HOME/storages/session-tree/ for durable branch state. The log stays resume-valid.
• Projection mode — if even the emulation is unavailable, navigation moves the tree projection and panel only, and the next turn keeps the canonical history.

Every mode is honest about itself: the Host log prints a one-time notice when a session runs in a non-native mode. Move the raw session.jsonl.zstd between machines together with the matching sidecar file.

How it works

• Append-only — every node is immutable; branching and jumping only move the cursor. Old branches are never edited or deleted.
• Every entry is a node — messages, tool calls, model switches, compaction records, and branch summaries all become typed nodes; each has a unique nodeId and a parentId (root is null). A node may have multiple children — that is the fork.
• Cursor navigation — jumping moves the active leaf to a historical node; the next append grows a new branch from there. Sibling branches stay intact.
• LLM context — the model always receives the standard messages array for the root→cursor path only.

Development (contributors)

The repository is a pnpm workspace building the three implementation packages standalone (no Harness checkout needed):

pnpm install
pnpm verify      # build + typecheck (host & client) + pack dry-run + vitest
pnpm pack:all    # produce the four tarballs

Tests run against the published Harness packages (0.2.1-rc.3) — the stock-mode paths — with vitest from the repository root. The same suite is green against 0.2.1-rc.2, the version bundled by the current desktop build. The browser spec in packages/client/ui-session-tree exercises both the 0.2 native right-Sidebar registration and the older overlay fallback in the standalone suite.

Source integration against a Harness checkout

For debugging against a 0.2.1 Harness source checkout (native branch switching and source integration):

dev/install.sh /path/to/deepseek-harness     # applies both dev patches + copies packages
cd /path/to/deepseek-harness && pnpm install && pnpm run build

See dev/README.md for what each patch does. This flow is for contributors only — user installs never touch a Harness checkout.

License

MIT.