Sandman-v2 concept-slice handoff: structure before prose (consumer 2)

Context

Consumer-2 leaf of epic #14472 — sandman handoff v2: report → map. Filed in the operator-directed full-fledging pass; live latest-open sweep 2026-07-02T19:37:34Z: no equivalent ticket.

Venue is settled authority: #14422 OQ2 ROUTED sandman-v2 into this epic (convergence-map v2, author-adopted; the #13444 owner's formal CONCUR on-record 2026-07-02) — HOME never owns the boot-handoff contract. Shape lean from the same record: Matrix-2 Option A, a pure graph-slice render (no HANDOFF node type; that falsifier stays live — if annotation write-back needs emerge, reopen under ADR 0024 discipline, don't drift into it).

The Problem

An agent boots into a summary, not a structure: resources/content/sandman_handoff.md narrates prose first, so a fresh-context peer reconstructs "what changed, where are the gaps, what do I own" by reading — the exact re-derivation the concept layer exists to kill. The graduation's design intent: boot into a concept-slice — concepts touched this session, edge deltas, per-concept open gaps — with prose LAST.

The Architectural Reality

• Generator: ai/services/graph/GoldenPathSynthesizer.mjs (synthesizeGoldenPath writes sandman_handoff.md via the centralized pipeline; the Computed Golden Path + route ledger already render inside it).
• Handoff-format SSOT registration exists and is binding — the #14458 review's one Required Action was exactly a missed format-registration; this leaf's render sections register the same way.
• Slice inputs all exist read-side: TAGGED_CONCEPT session anchors (ai/services/graph/SemanticGraphExtractor.mjs), edge state via GraphService, gap classes via GapInferenceEngine.mjs.
• The shared-consumable contract (binding AC, carried from the graduation's criterion-6 + the epic-boundary owner's fold-ready clause): the render model's slice contract — input: bounded concept neighborhood + four-axis tier/provenance annotations; output: render tree — is a named, exported consumable, so the v14 self-view/constellation (#13444, ADR-0031 §1) CONSUMES the same contract instead of forking a second renderer. Render≠memory doctrine: the slice renders state; it never becomes a memory substrate itself.

The Fix

One PR:

1. Slice builder module (ai/services/graph/, sibling pattern): {sessionWindow} → {conceptsTouched[], edgeDeltas[], perConceptGaps[]} — read-only, four-axis annotations per element, absent-as-absent.
2. Render sections INTO the handoff, structure before prose: ## Concept Slice (touched concepts w/ tier badges) → ## Edge Deltas (new/reinforced/decayed since last handoff) → ## Open Gaps per Concept (from the gap queues, concept-keyed) → existing narrative LAST.
3. The exported slice contract — one module boundary named in JSDoc as the shared consumable (buildConceptSlice(options): SliceRenderTree), with the four-axis annotation schema documented at the export.
4. Format SSOT registration for each new section (the #14458 lesson, pre-empted).

Contract Ledger Matrix

Decision Record impact

aligned-with ADR 0024 (no new node classes → the #14426 post-sync canary obligation does not trigger; asserted in-spec). Feeds ADR-0031 §1 (Institution-Cockpit render-model) as its consumed input — coordinate wording with the #14445 co-authors at PR time.

Acceptance Criteria

• Slice builder module + hermetic spec (fixture graph; zero writes asserted)
• Handoff renders the three sections structure-first; narrative last; slice failure degrades to narrative-only with a logged warn
• Four-axis annotations rendered where present, absent-as-absent
• buildConceptSlice exported + JSDoc-documented as the shared consumable; no second render model minted anywhere in the diff
• Format SSOT registration for all new sections
• No new node/edge classes (spec-asserted)
• PR Resolves this leaf, Refs #14472

Out of Scope

• HANDOFF node type / annotation write-back (Matrix-2 B — reopen-on-falsifier only).
• The v14 self-view/constellation rendering itself (#13444 leaves; they consume the contract).
• Concept extraction changes (mint-side belongs to #14502's guard).

Avoided Traps

• Renderer fork — the one contract serves both the nightly handoff and the v14 cockpit; forking is the named failure the OQ2 clause exists to prevent.
• Write-back drift — a "small" ack/dismiss field on the slice is the HANDOFF-node decision by stealth; falsifier-gated, not incremental.
• Prose-first relapse — the section ORDER is the feature; a spec pins structure-before-narrative.

Sequencing

Executable now (all inputs read-side). Benefits from #14502 (unified spine) and #14474 (axis-presence reality) but hard-blocked by neither — the slice renders what exists.

Related: #14472 (parent epic), #13444 + #14445/ADR-0031 (the consuming boundary), #14502, #14474, Discussion #14422 (OQ2 + Matrix-2 + criterion 6)

Origin Session ID: 8cf234b7-e698-47ca-99e2-bf865196b6aa

Retrieval Hint: sandman v2 concept slice handoff render shared consumable contract structure before prose