Validate pair content seed rerolls

tools/prompt_route_simulation.py

@@ -936,6 +936,7 @@ def _pair_seed_snapshot(pair: dict[str, Any]) -> dict[str, Any]:
         "soft_scene_text": soft_row.get("scene_text"),
         "hard_scene_text": hard_row.get("scene_text"),
         "soft_item": soft_row.get("item"),
+        "soft_pose": soft_row.get("pose"),
         "hard_item": hard_row.get("item"),
         "hard_position_key": hard_row.get("position_key"),
         "hard_position_keys": hard_row.get("position_keys") or [],
@@ -1105,6 +1106,53 @@ def _pair_seed_pose_reroll_check(seed: int) -> dict[str, Any]:
     }
 
 
+def _pair_seed_content_reroll_check(seed: int) -> dict[str, Any]:
+    name = "pair_seed.content_reroll"
+    base = _pair_seed_probe(seed)
+    base_snapshot = _pair_seed_snapshot(base)
+    changed = False
+    changed_seed = None
+    changed_field_names: list[str] = []
+    issues: list[str] = []
+    stable_fields = (
+        "shared_cast_descriptors",
+        "soft_cast_descriptor_text",
+        "hard_cast_descriptor_text",
+        "soft_scene_text",
+        "hard_scene_text",
+        "hard_item",
+        "hard_position_key",
+        "hard_source_role_graph",
+        "soft_composition",
+        "hard_composition",
+    )
+    changed_fields = ("soft_item", "soft_pose")
+    for reroll_seed in range(seed + 1, seed + 16):
+        rerolled = _pair_seed_probe(seed, reroll_axis="content", reroll_seed=reroll_seed)
+        rerolled_snapshot = _pair_seed_snapshot(rerolled)
+        field_issues = _same_fields_issues(name, base_snapshot, rerolled_snapshot, stable_fields, reroll_seed)
+        if field_issues:
+            issues.extend(field_issues)
+            break
+        changed_field_names = [
+            field for field in changed_fields if base_snapshot.get(field) != rerolled_snapshot.get(field)
+        ]
+        if changed_field_names:
+            changed = True
+            changed_seed = reroll_seed
+            break
+    if not changed:
+        issues.append("pair content reroll did not change soft_item or soft_pose within 15 attempts")
+    return {
+        "name": name,
+        "base": _row_summary(base.get("softcore_row") or {}),
+        "changed": changed,
+        "changed_seed": changed_seed,
+        "changed_fields": changed_field_names,
+        "issues": issues,
+    }
+
+
 def _seed_axis_checks(seed: int) -> list[dict[str, Any]]:
     return [
         _seed_determinism_check(seed),
@@ -1144,6 +1192,7 @@ def _seed_axis_checks(seed: int) -> list[dict[str, Any]]:
 def _pair_seed_checks(seed: int) -> list[dict[str, Any]]:
     return [
         _pair_seed_determinism_check(seed),
+        _pair_seed_content_reroll_check(seed),
         _pair_seed_pose_reroll_check(seed),
     ]