From e329c50fa36ab2e5f51b50cbe4ac762e37555e67 Mon Sep 17 00:00:00 2001
From: Khalim Conn-Kowlessar <kconnkowlessar@gmail.com>
Date: Thu, 9 Jul 2026 13:13:23 +0000
Subject: [PATCH] =?UTF-8?q?Fabric-first=20phase=202=20re-scores=20candidat?=
 =?UTF-8?q?es=20in=20the=20goal=20objective's=20currency=20=F0=9F=9F=A9?=
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Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 domain/modelling/optimisation/optimiser.py | 30 ++++++++++++----------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/domain/modelling/optimisation/optimiser.py b/domain/modelling/optimisation/optimiser.py
index 2f556e2a2..57976c4ca 100644
--- a/domain/modelling/optimisation/optimiser.py
+++ b/domain/modelling/optimisation/optimiser.py
@@ -276,7 +276,7 @@ def optimise_package_fabric_first(
     )
     if (
         target_sap is not None
-        and fabric_package.score.sap_continuous >= target_sap
+        and objective(fabric_package.score) >= target_sap
     ):
         return fabric_package
     if not fabric_package.selected:
@@ -326,13 +326,15 @@ def optimise_package_fabric_first(
             remaining_groups,
             post_fabric_scorer,
             baseline_epc,
-            start_sap=fabric_package.score.sap_continuous,
+            objective=objective,
+            start_value=objective(fabric_package.score),
         ),
         scorer=post_fabric_scorer,
         baseline_epc=baseline_epc,
         budget=leftover_budget,
         target_sap=target_sap,
         dependencies=outstanding_dependencies,
+        objective=objective,
     )
     return OptimisedPackage(
         selected=[*fabric_package.selected, *top_up.selected],
@@ -353,23 +355,25 @@ def _rescored_groups(
     scorer: Scorer,
     baseline_epc: EpcPropertyData,
     *,
-    start_sap: float,
+    objective: Callable[[Score], float],
+    start_value: float,
 ) -> list[list[ScoredOption]]:
     """The groups with every Option's role-1 warm-start signal re-scored
-    through ``scorer`` — for phase 2, its independent gain on the post-fabric
-    dwelling rather than the raw baseline, so options whose worth changes once
-    the envelope is treated (a boiler on an insulated home) are re-ranked.
-    ``start_sap`` is the score of ``baseline_epc`` through ``scorer`` with no
-    candidate applied — the caller already has it (the phase-1 package score),
-    so it is threaded in rather than re-computed."""
+    through ``scorer`` in the ``objective``'s currency — for phase 2, its
+    independent gain on the post-fabric dwelling rather than the raw baseline,
+    so options whose worth changes once the envelope is treated (a boiler on
+    an insulated home) are re-ranked. ``start_value`` is the objective value of
+    ``baseline_epc`` through ``scorer`` with no candidate applied — the caller
+    already has it (the phase-1 package score in the objective's currency), so
+    it is threaded in rather than re-computed."""
     return [
         [
             ScoredOption(
                 option=scored.option,
-                sap_gain=scorer.score(
-                    baseline_epc, [scored.option.overlay]
-                ).sap_continuous
-                - start_sap,
+                sap_gain=objective(
+                    scorer.score(baseline_epc, [scored.option.overlay])
+                )
+                - start_value,
             )
             for scored in group
         ]