dsh-session-map

Adds a third tab to the DSH conversation view: a draggable, zoomable map of your session tree.

It answers the question the native session list cannot:

Which message, in which conversation, did this thread branch off from — and how many branches hang under it?

The native list is a line. Parent/child shows up as indentation, and once a tree has several branches the children all look the same. This plugin draws the tree as a map: click a node, you switch to that session.

What it looks like

        [root · linear transform]
               │
          [linear map]  ← parent, always directly above
               │
   ┌───────────┴───────────┐
 [image & kernel]     [isomorphism test]   ← children, spread across the lower half
      ＼                  ／
      [injective & surjective]  [kernel & image] …   ← shrinks automatically at 3+ children

The centre is the current session (the focus), the parent sits directly above, and children spread across the lower semicircle — the entire upper half is reserved for the parent. That rule is not just aesthetics: node cards are wide (276 px at the centre), so a child landing at dead-left or dead-right has its connecting line completely swallowed by the card, and the picture reads as "no line at all". (That was a real defect in v0.1.0, fixed in v0.1.1 — see the regression guard under Known limitations.)

• Click a node → switch to that session. (A click that ends a drag does not count, so panning never switches you by accident.)
• Whole-tree toggle lays the entire tree out at once (radial tidy-tree + layered guide rings).
• Drag = pan; wheel = zoom anchored at the pointer (same feel as a game map). There are also − / ＋ buttons and a "fit everything" button.
• A breadcrumb across the top shows the path from the current focus to the root; the right side shows depth N · M branches.
• Status dot in each node's upper-right corner: running (cyan) / waiting for you (amber) / done (dim).

Install

dsh plugin --profile web add dsh-session-map

Uninstall

dsh plugin --profile web remove dsh-session-map

This plugin does not modify any built-in code. It is purely additive; once removed, the environment is exactly as it was.

Structure

dsh-session-map/
├── package.json          # manifest: dsh.bundle.patch + dsh.client
├── cordis.patch.yml      # bundle layer: inserts itself into the config tree
├── dsh/
│   ├── index.js          # host half (Node) — deliberately empty, see below
│   └── client.js         # client half (browser) — all of the implementation
└── README.md

Why the host half is empty

dsh/index.js exports only name / inject = [] / apply(_ctx) {} and does nothing.

There is exactly one reason: the Cordis config tree needs a resolvable module entry point for the bundle to attach. Every capability this plugin has lives on the UI side; the host side has nothing to do. So it registers no routes, no services, reads no config — what it changes = zero.

Why the client half looks the way it does

An external plugin's client bundle goes through the DSH shell's lazy-CJS protocol:

window.__ModuleLoader__.load({
  id: 'dsh-session-map',
  factory: function (require) {
    var React = require('react')   // use the shell's copy; do not bundle your own
    // ...
    return { apply: apply, inject: ['slots', 'sessions'], __internals: { ... } }
  }
})

React must come from require('react') — the shell's own copy. Bundling your own React means hooks cannot see the shell's runtime context.

Mount point

Registered into the conversation.view seat (a list-type seat; the built-in UI ships two tabs, "Conversation" and "Traces"):

scope.slots.inject('conversation.view', function () {
  return scope.slots.register({
    name: 'conversation.view',
    id: 'session-tree',
    order: 20,                 // after Traces
    label: 'Tree map',
    inject: function (sessionId) {
      return {
        sessionId: sessionId,
        open: function (id) { scope.sessions.open(id) }
      }
    }
  }, TreeMap)
})

Known limitations

Ordered by severity.

• 🔴 It gets crowded at n≥5. If the centre session has more than 5 direct branches, the lower semicircle cannot hold cards that wide and adjacent nodes overlap. The root cause is a geometric hard limit: cards are 208 px wide, the container is only ~720 px, and 5 cards need 1040 px. But real data almost never hits this — across 69 real sessions scanned, a user's own conversation had at most 2 branches; the sessions with many children (e.g. 23) were all subagents.
• 🟠 Subagent sessions appear in the tree. The data-side reason for the previous point: DSH's useSessions.ids includes all 69 sessions, 34 of which are subagents. The plugin currently treats them all alike.
• 🟡 Whole-tree view is bounded by window size. Large trees require zooming out, which shrinks the text — an inherent cost of a canvas, not a bug. Use focus mode for detail.
• 🟡 Dragging has no inertia or bounds. The feel is "tracks your hand", not "flings and coasts". Deliberate.
• 🟡 Only parentId is honoured. An empty session whose parent has not been persisted yet shows as "upstream" but cannot be clicked through; say something inside it and it persists.
• ⚪ label is not localised — hardcoded English "Tree map".
• ⚪ No HMR wiring: editing client.js takes effect on page refresh (the bundle route derives its rev from the content hash). "No DSH restart needed" was measured, not documented.

A regression guard

v0.1.0 had a real defect: at n=2 the children landed at dead-left and dead-right (±90°), and with Rx=223 against "centre half-width 138 + child half-width 104 = 242", the entire connecting line hid under the cards — 3 nodes on screen, 0 lines, reading as "feature not implemented". There is now a dedicated assertion guarding it (a visibleLen sampling method requiring every centre↔child visible segment to exceed 22 px, scanned over n=1..4). Whoever next touches the angles in layoutFocus will trip it first.

Other limits, stated plainly

• The virtual root is a display-only grouping node, not a session that exists in DSH. It adds one node at the "root" level (the real root count is the N written in its title).
• Forking from a source session with no completed turn is rejected by the host (session/fork-unavailable); the plugin reports this honestly and retries once against the current main session, recording the fallback rather than hiding it.

License

MIT