diff --git a/src/lib/code-reviews/prompts/generate-prompt.ts b/src/lib/code-reviews/prompts/generate-prompt.ts
index aff24aaa6e..da6880b587 100644
--- a/src/lib/code-reviews/prompts/generate-prompt.ts
+++ b/src/lib/code-reviews/prompts/generate-prompt.ts
@@ -273,8 +273,22 @@ export async function generateReviewPrompt(
       .replace(/{PREVIOUS_SUMMARY}/g, existingReviewState.summaryComment.body)
       .replace(/{ACTIVE_COMMENT_COUNT}/g, String(activeCount));
     prompt += replacePlaceholders(incrementalWorkflow) + '\n\n';
+    logExceptInTest('[generateReviewPrompt] Using incremental workflow', {
+      reviewId,
+      previousHeadSha: previousHeadSha.substring(0, 8),
+    });
   } else {
     prompt += replacePlaceholders(template.workflow) + '\n\n';
+    if (previousHeadSha) {
+      logExceptInTest(
+        '[generateReviewPrompt] Falling back to full workflow despite previousHeadSha',
+        {
+          reviewId,
+          hasIncrementalTemplate: !!template.incrementalReviewWorkflow,
+          hasSummaryComment: !!existingReviewState?.summaryComment,
+        }
+      );
+    }
   }
 
   // 6. What to review
diff --git a/src/lib/code-reviews/triggers/prepare-review-payload.ts b/src/lib/code-reviews/triggers/prepare-review-payload.ts
index e0ad075c8d..d9e2fc9702 100644
--- a/src/lib/code-reviews/triggers/prepare-review-payload.ts
+++ b/src/lib/code-reviews/triggers/prepare-review-payload.ts
@@ -322,7 +322,16 @@ export async function prepareReviewPayload(
     // continuation) are derived from the same review row to avoid mismatches.
     let previousHeadSha: string | null = null;
     let previousCloudAgentSessionId: string | undefined;
-    const incrementalEnabled = await isFeatureFlagEnabled(FEATURE_FLAG_INCREMENTAL_REVIEW);
+    const incrementalEnabled = await isFeatureFlagEnabled(
+      FEATURE_FLAG_INCREMENTAL_REVIEW,
+      owner.userId
+    );
+
+    logExceptInTest('[prepareReviewPayload] Incremental review flag evaluated', {
+      reviewId,
+      incrementalEnabled,
+      ownerId: owner.userId,
+    });
 
     if (incrementalEnabled) {
       try {
@@ -345,6 +354,11 @@ export async function prepareReviewPayload(
               previousCloudAgentSessionId,
             }
           );
+        } else {
+          logExceptInTest(
+            '[prepareReviewPayload] No previous completed review found, using full review',
+            { reviewId }
+          );
         }
       } catch (error) {
         // Non-critical - fall back to full review