1 files changed, 37 insertions, 17 deletions
diff --git a/src/gap_pipeline/kernel_models.py b/src/gap_pipeline/kernel_models.py
index 32abf39..f835473 100644
--- a/src/gap_pipeline/kernel_models.py
+++ b/src/gap_pipeline/kernel_models.py
@@ -38,6 +38,11 @@ class ProofDAG(StrictModel):
     def node_ids(self) -> list[str]:
         return [node.node_id for node in self.nodes]
 
+    def leaf_node_ids(self) -> list[str]:
+        """Return source leaves: nodes with no prerequisite dependencies."""
+
+        return [node.node_id for node in self.nodes if not node.dependencies]
+
     @model_validator(mode="after")
     def validate_graph(self) -> "ProofDAG":
         node_ids = self.node_ids()
@@ -113,6 +118,8 @@ class ReplacementChange(StrictModel):
         ]
         if any(not value.strip() for value in text_fields):
             raise ValueError("replacement fields must be non-empty")
+        if not re.fullmatch(r"slot[1-9][0-9]*", self.slot_id):
+            raise ValueError("replacement slot IDs must be slot1, slot2, ...")
         if self.original_value.strip() == self.replacement_value.strip():
             raise ValueError("replacement must differ from the original value")
         return self
@@ -140,6 +147,34 @@ class ReplacementPlan(StrictModel):
         }
         if unknown:
             raise ValueError(f"replacement plan references unknown nodes {sorted(unknown)}")
+        leaves = set(dag.leaf_node_ids())
+        non_leaf = {
+            change.source_node_id
+            for change in self.changes
+            if change.source_node_id not in leaves
+        }
+        if non_leaf:
+            raise ValueError(
+                "replacement plan must target source leaf nodes; "
+                f"received {sorted(non_leaf)}"
+            )
+        return self
+
+    def validate_repair_of(
+        self,
+        previous: "ReplacementPlan",
+    ) -> "ReplacementPlan":
+        current_targets = [
+            (change.slot_id, change.source_node_id) for change in self.changes
+        ]
+        previous_targets = [
+            (change.slot_id, change.source_node_id)
+            for change in previous.changes
+        ]
+        if current_targets != previous_targets:
+            raise ValueError(
+                "repair must preserve replacement slot IDs and source leaf nodes"
+            )
         return self
 
 
@@ -234,13 +269,11 @@ class CandidateBundle(StrictModel):
 class JudgeVerdict(StrictModel):
     verdict: Literal["accept", "reject"]
     step_by_step_check: str
-    replacement_check: str
     blocking_issues: str = ""
     patch_suggestion: str = ""
 
     @field_validator(
         "step_by_step_check",
-        "replacement_check",
         "blocking_issues",
         "patch_suggestion",
         mode="before",
@@ -279,7 +312,6 @@ class JudgeVerdict(StrictModel):
     def validate_coverage(
         self,
         dag: ProofDAG,
-        replacement_plan: ReplacementPlan,
     ) -> "JudgeVerdict":
         missing_nodes = [
             node_id
@@ -290,20 +322,8 @@ class JudgeVerdict(StrictModel):
             )
             is None
         ]
-        missing_slots = [
-            change.slot_id
-            for change in replacement_plan.changes
-            if re.search(
-                rf"(?<![A-Za-z0-9_]){re.escape(change.slot_id)}(?![A-Za-z0-9_])",
-                self.replacement_check,
-            )
-            is None
-        ]
-        if missing_nodes or missing_slots:
-            raise ValueError(
-                "judge coverage incomplete: "
-                f"nodes={missing_nodes}, slots={missing_slots}"
-            )
+        if missing_nodes:
+            raise ValueError(f"judge coverage incomplete: nodes={missing_nodes}")
         return self