diff --git a/tools/push3-evolution/evolve.sh b/tools/push3-evolution/evolve.sh
index 89624ff..640d391 100755
--- a/tools/push3-evolution/evolve.sh
+++ b/tools/push3-evolution/evolve.sh
@@ -452,7 +452,8 @@ for gen in $(seq 0 $((GENERATIONS - 1))); do
 
     CAND_IDX="${CAND_FILE##*candidate_}"
     CAND_IDX="${CAND_IDX%.push3}"
-    CID="gen${gen}_c${CAND_IDX}"
+    # Canonical candidate_id format: "candidate_XXX" (matches source filename and batch-eval IDs).
+    CID="candidate_${CAND_IDX}"
 
     # Read mutations_applied from sidecar; default 0 if missing.
     OPS_FILE="${CAND_FILE%.push3}.ops"