diff --git a/app/gitea.js b/app/gitea.js
index 6e24475..1a5c849 100644
--- a/app/gitea.js
+++ b/app/gitea.js
@@ -34,7 +34,8 @@ export async function getCommitMessageBySha(sha) {
       httpsAgent,
     });
     return resp.data?.message || '';
-  } catch {
+  } catch (e) {
+    console.log(`  ⚠️  bot-check: 讀取 commit sha=${sha} 失敗: ${e.message}`);
     return '';
   }
 }
@@ -49,17 +50,39 @@ export async function getBranchHeadCommitMessage(branch = PR_HEAD_BRANCH) {
     });
     const sha = resp.data?.commit?.id || resp.data?.commit?.sha || '';
     return await getCommitMessageBySha(sha);
-  } catch {
+  } catch (e) {
+    console.log(`  ⚠️  bot-check: 讀取 branch=${branch} head commit 失敗: ${e.message}`);
     return '';
   }
 }
 
 export async function shouldSkipBotCommit({ sha = PR_HEAD_SHA || process.env.GITHUB_SHA, branch = PR_HEAD_BRANCH } = {}) {
-  const candidates = [
-    await getCommitMessageBySha(sha),
-    await getBranchHeadCommitMessage(branch),
-  ].filter(Boolean);
-  return candidates.some(message => message.includes('[ai-review-bot]'));
+  console.log(`  🔎 bot-check: start sha=${sha || 'empty'} branch=${branch || 'empty'}`);
+
+  const shaMessage = await getCommitMessageBySha(sha);
+  if (sha) {
+    console.log(`  🔎 bot-check: sha=${sha} message=${shaMessage ? 'found' : 'empty'}`);
+    if (shaMessage.includes('[ai-review-bot]')) {
+      console.log('  ✅ bot-check: matched commit sha marker');
+      return true;
+    }
+  } else {
+    console.log('  🔎 bot-check: skip sha lookup because sha is empty');
+  }
+
+  const branchMessage = await getBranchHeadCommitMessage(branch);
+  if (branch) {
+    console.log(`  🔎 bot-check: branch=${branch} head_message=${branchMessage ? 'found' : 'empty'}`);
+    if (branchMessage.includes('[ai-review-bot]')) {
+      console.log('  ✅ bot-check: matched branch head marker');
+      return true;
+    }
+  } else {
+    console.log('  🔎 bot-check: skip branch lookup because branch is empty');
+  }
+
+  console.log('  ℹ️  bot-check: no [ai-review-bot] marker found');
+  return false;
 }
 
 /**