docs/current-handoff.md

@@ -528,6 +528,83 @@ The distinction is clearly useful enough that focused→global integration shoul
 
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+## Focused Investigation Overlay Workspace — Checkpoint (2026-08-26)
+
+### Implemented workspace state (settled, post-commit abeb3fc)
+
+The focused investigation overlay workspace has been built and committed. The following describe the **actual implemented** behaviour:
+
+#### Case overview = orientation / index surface
+- The case overview is the primary orientation and navigation surface.
+- It displays Current Understanding, Situation, and Open Questions.
+- Open Questions serve as top-level investigation entry points.
+
+#### Investigation opens as an overlay
+- Selecting an Open Question opens a focused investigation workspace as a large overlay.
+- The case overview remains visible but dimmed behind the overlay.
+- Background interaction is locked while investigating.
+- Page scrolling is locked while investigating.
+- The workspace itself owns its own scrolling.
+- Close investigation is persistently available (top-right).
+
+#### Overlay close behaviour
+- Closing preserves all investigation state — it does not complete the branch.
+- Reopening restores accumulated investigation context.
+- Investigation state persists across open/close cycles.
+
+#### Two-column layout on wide screens
+- The workspace uses a two-column layout:
+  - Primary prominence: active investigation (current question, response, "What this tells us", Still unclear)
+  - Supporting context: Previous Learning beneath the primary column
+- Narrow screens collapse to a single column naturally — responsive presentation does not alter reasoning semantics.
+
+#### Workspace navigation controls
+- "Back to open questions" and "Done for now" appear only in appropriate states as workspace-level navigation.
+
+#### Attention model (implemented)
+> The UI should progressively reflect the reasoning state.
+>
+> - The thing currently being investigated receives prominence.
+> - Accumulated learning remains available as context without competing equally for attention.
+> - The interface should not display every reasoning artifact with equal prominence simultaneously.
+
+#### LLM call boundary
+- No additional LLM calls were introduced by the workspace itself.
+- All reasoning output volume from a focused turn (findings, uncertainties, assumptions, relationships, follow-ups) remains within the existing deconstruction call.
+
+---
+
+### Next direction: Findings validation surface
+
+"Do not implement it." Record this as the next product/reasoning interaction to explore:
+
+**"What this tells us" is the user-facing validation surface for Findings.**
+
+#### Default acceptance / exception pattern
+- A displayed Finding under "What this tells us" is **accepted by default** — no explicit Agree action is required.
+- The user intervenes only on exception.
+- Two exception actions:
+  - **"Not quite"** → correct/reword the Finding; original engine wording must be preserved in provenance (never silently overwritten).
+  - **"Not relevant"** → removes the Finding from active relevance while preserving its provenance.
+
+#### Unresolved items to carry forward
+The following remain unresolved — do not attempt to answer them in the next iteration:
+
+- **Exact "Not quite" editing interaction** — how correction is triggered, presented, and confirmed
+- **Exact Finding persistence/update mechanics** — runtime storage schema, identity model
+- **How corrected wording relates to original Finding identity** — same Finding revised vs. new Finding with lineage
+- **When Findings become eligible for later global synthesis** — eligibility criteria are undefined
+- **Exact "learned enough" condition** — no fixed threshold; synthesis remains a deliberate workshop-style checkpoint, not an automatic trigger
+
+#### Global synthesis constraint (preserved from prior handoff)
+> Cumulative Findings should NOT automatically be injected into every graph-update LLM call.
+>
+> A later global synthesis should occur at a natural workshop checkpoint, likely when useful questioning is exhausted or the user explicitly indicates they have enough information.
+
+This remains an intentional constraint — not an oversight. The reasoning pipeline and the validation/synthesis surfaces serve different purposes and must remain architecturally separable.
+
+---
+
 ## Focused → Global Finding Handoff Contract — August 2026
 
 ### Semantic contract (established)