D-EPI-COT C3b: scent ranks candidate mediators by testability

.claude/board/entries/2026-10-28-d-epi-cot-c3b-scent.md

@@ -0,0 +1,20 @@
+# D-EPI-COT-C3B: scent ranks candidate mediators by testability, not raw uncertainty
+
+**Status:** TEST-PINNED (fixture world). Code: `crates/lance-graph-planner/src/nars/scent.rs`. Doc: `docs/research/epistemic-cot/c3b-scenting.md`.
+
+## Decision
+
+- `scent` ranks candidate mediators of an `A → Y` edge. Testable leads come first: one link is bound in the sealed chain and grounded in the ledger, and the other link is missing. Within a status, leads are ordered by uncertainty (binary entropy of the NARS expectation).
+- It reads only. It writes no edge, truth or certification, and it stores no state.
+- A settled lead reopens as contested on independent contradiction. The edge keeps its certification.
+
+## Evidence
+
+- 6 tests; 4 disables, each red.
+- On the fixture, scent hydrates the true mediator in 1 investigation. Uncertainty-only ordering takes 4, because all four candidates have uncertainty 1.0.
+
+## Open
+
+- One world, one seed; extend STAUNEN-0 with this ranking.
+- No budget, habituation or learning-progress terms.
+- Maturation bits 50..52 are unwritten (order for new readings: `7 = Staunen … 0 = Wisdom`).

.claude/board/entries/README.md

@@ -25,13 +25,14 @@ index row, (3) no duplicate entry id. Checks 1 and 2 are deliberately
 opposite directions; the stranding this convention prevents shows up in
 exactly one of them, never both.
 
-497 entries, 2026-08-06 .. 2026-10-28.
+498 entries, 2026-08-06 .. 2026-10-28.
 
 | date | entry id | finding | file |
 |---|---|---|---|
 | 2026-10-28 | `thought-layers-nan-skip` |  | [2026-10-28-thought-layers-nan-skip.md](2026-10-28-thought-layers-nan-skip.md) |
 | 2026-10-28 | `lane-layout-from-classview` |  | [2026-10-28-lane-layout-from-classview.md](2026-10-28-lane-layout-from-classview.md) |
 | 2026-10-28 | `D-SAG-6-1` |  | [2026-10-28-d-sag-6-1-audit-reference-ledger.md](2026-10-28-d-sag-6-1-audit-reference-ledger.md) |
+| 2026-10-28 | `D-EPI-COT-C3B` |  | [2026-10-28-d-epi-cot-c3b-scent.md](2026-10-28-d-epi-cot-c3b-scent.md) |
 | 2026-10-28 | `D-EPI-COT` |  | [2026-10-28-d-epi-cot-c0-c2.md](2026-10-28-d-epi-cot-c0-c2.md) |
 | 2026-10-28 | `D-DT64-6` |  | [2026-10-28-d-dt64-6-routing-bindstore-behavior.md](2026-10-28-d-dt64-6-routing-bindstore-behavior.md) |
 | 2026-10-28 | `D-DT64-6-1a` |  | [2026-10-28-d-dt64-6-ogit-predicates-impl.md](2026-10-28-d-dt64-6-ogit-predicates-impl.md) |

crates/lance-graph-planner/src/nars/mod.rs

@@ -18,6 +18,7 @@ pub mod insights;
 pub mod meta_basin;
 pub mod reach_out;
 pub mod regulate;
+pub mod scent;
 pub mod stance;
 pub mod support;
 pub mod tactic_select;