spec(learned-decision-engine): engine becomes triage where a demonstration oracle exists

Req 6.5 (maintainer decision 2026-10-05, with search-with-proof): BLOCK comes from
verified demonstrations; the engine is judged by top-K recall per push and advisory
false alarms; the pooled block gate governs only families without an oracle.
Task 17 adds the metric and re-scores existing arms at no cost.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

.kiro/specs/learned-decision-engine/requirements.md

@@ -132,6 +132,13 @@ rule hits.
    - **t_quiet**: per family, the highest threshold keeping >= 90% of the paired positives at or above it (chosen
      on training folds, its held-out recall reported); findings below it are silent.
    - No held-out label moves a threshold or a normalisation map; candidates whose verdict is `unsure` never block.
+5. *(Amended 2026-10-05, maintainer decision, with `search-with-proof`.)* Where a family has an owned demonstration
+   oracle, the engine is **triage, not the gate**: BLOCK comes only from a verified demonstration (`search-with-proof`
+   Req 3, 6.3), and the engine's job is to put the true vulnerable function among the top K candidates of a push.
+   For those families the engine is judged by (a) top-K recall per push (K = 3 to start) on the unseen-repo pool and
+   (b) its advisory false-alarm rate there; the pooled block gate of 6.4 then governs only families without an
+   oracle (access control, deserialisation, configuration and secrets), where the engine remains the only signal.
+   Every arm reports top-K recall next to its catch and false-alarm rates.
 
 ### Requirement 7: Built for unseen repositories -- a repo safety net
 

.kiro/specs/learned-decision-engine/tasks.md

@@ -254,3 +254,13 @@ rate per push. Within-pair AUC stays a development signal. Tasks 11-14 below fol
   - Search input fields, retrieval parameters, k, instruction and demonstrations together (DSPy MIPRO-style) on
     training folds; no hand-set input profile. Budget go-ahead before paid search.
   - _Requirements: 3, 6, 7_
+
+- [ ] 17. Triage objective (Req 6.5, amended 2026-10-05 with `search-with-proof`)
+  - [ ] 17.1 Metric: top-K recall per push (K = 1, 3, 5) of the true vulnerable function among changed functions,
+    on held-out folds and on the unseen-repo pool; added to the pool scorer next to catch and false alarm.
+  - [ ] 17.2 Score the existing arms on it ($0 replay): trained logistic (cheapest per candidate, likely default),
+    LLM programs (exp-005 A), engine-evidence ordering, and an averaged ensemble.
+  - [ ] 17.3 Re-scope 14 (pooled block gate) to families without a demonstration oracle; 15.4 and 16 report top-K
+    recall as their primary unseen-pool number for families with an oracle.
+  - _Requirements: 6.5, 7_
+