diff --git a/.env b/.env
index 94c0fc4..2995b09 100644
--- a/.env
+++ b/.env
@@ -23,7 +23,7 @@ hmac = 8aU8WnITYhwaGTXH
 PROMOTION_LLM_URL=http://chat.taimed.cn/v1/chat/completions
 PROMOTION_LLM_MODEL=your-model-name
 PROMOTION_LLM_TIMEOUT=30
-PROMOTION_LLM_FALLBACK=""
+PROMOTION_LLM_FALLBACK="We would like to cordially invite you to consider submitting a manuscript to {{journal_name}}."
 PROMOTION_LLM_ADVISED_FALLBACK=""
 
 [journal]
diff --git a/application/common/PromotionLlmService.php b/application/common/PromotionLlmService.php
index 9651b4f..208b387 100644
--- a/application/common/PromotionLlmService.php
+++ b/application/common/PromotionLlmService.php
@@ -97,6 +97,11 @@ class PromotionLlmService
         $journalAims = trim((string)($journal['aims'] ?? ''));
         $journalDbs  = trim((string)($journal['databases'] ?? ''));
 
+        // advised_topics 目标数量：期望邮件里总是体现 3 个推荐方向
+        $targetTopicCount = 3;
+        $overlapCount = count($overlapList);
+        $needFill = max(0, $targetTopicCount - $overlapCount);
+
         $system = 'You are an academic editorial assistant. '
             . 'You will receive context about an author, their recent paper, and a target journal, '
             . 'and you must produce TWO English paragraphs for an invitation email. '
@@ -106,12 +111,17 @@ class PromotionLlmService
             . '(a) briefly appreciate the author\'s recent paper, '
             . '(b) explain why it fits the journal\'s scope, '
             . '(c) gently invite a future submission. '
-            . 'Rules for "advised_topics": 1-2 sentences, <=40 words; '
-            . 'emphasize that the journal is particularly interested in the research directions '
-            . 'where the journal\'s focus and the author\'s work overlap; '
-            . 'mention the overlapping topics explicitly (use the provided overlap list when non-empty, '
-            . 'otherwise choose the best semantic overlap between journal focus and author fields); '
-            . 'end by inviting contributions leaning toward those directions. '
+            . 'Rules for "advised_topics": 1-2 sentences, <=60 words; '
+            . 'Must recommend EXACTLY ' . $targetTopicCount . ' research directions the journal is particularly interested in, '
+            . 'and explicitly list these ' . $targetTopicCount . ' topics in the sentence. '
+            . 'Topic selection rules, in order: '
+            . '(i) include all items from "Overlap topics (exact match)" first, preserving their order; '
+            . '(ii) if overlap has fewer than ' . $targetTopicCount . ' items, fill the remaining slots '
+            . 'with topics that are semantically close to BOTH the journal\'s focus fields and the author\'s research fields '
+            . '(prefer concrete sub-topics over generic umbrella terms; '
+            . 'do NOT invent topics unrelated to either list); '
+            . '(iii) never repeat topics, keep wording concise (2-4 words each). '
+            . 'End the paragraph by inviting contributions leaning toward those directions. '
             . 'No greetings, no signatures, no placeholders, no markdown, no code fences. '
             . 'If a section genuinely cannot be produced, return an empty string for that key.';
 
@@ -129,9 +139,13 @@ class PromotionLlmService
             $userLines[] = 'Journal focus fields: ' . implode(', ', $journalList);
         }
         if (!empty($overlapList)) {
-            $userLines[] = 'Overlap topics (exact match): ' . implode(', ', $overlapList);
+            $userLines[] = 'Overlap topics (exact match): ' . implode(', ', $overlapList)
+                . ' [count=' . $overlapCount . ', need_fill=' . $needFill . ']';
         } else {
-            $userLines[] = 'Overlap topics (exact match): (none, infer semantically from the two field lists above)';
+            $userLines[] = 'Overlap topics (exact match): (none) '
+                . '[count=0, need_fill=' . $targetTopicCount
+                . '; please pick ' . $targetTopicCount
+                . ' semantically related topics from the two field lists above]';
         }
         if ($journalAims !== '') {
             $userLines[] = 'Journal aims & scope: ' . mb_substr($journalAims, 0, 500);
@@ -139,6 +153,7 @@ class PromotionLlmService
         if ($journalDbs !== '') {
             $userLines[] = 'Journal indexing: ' . mb_substr($journalDbs, 0, 200);
         }
+        $userLines[] = 'Advised topics required count: ' . $targetTopicCount;
         $userLines[] = 'Return only minified JSON {"description":"...","advised_topics":"..."}.';
         $user = implode("\n", $userLines);
 
diff --git a/application/common/PromotionService.php b/application/common/PromotionService.php
index 9628ef7..666a332 100644
--- a/application/common/PromotionService.php
+++ b/application/common/PromotionService.php
@@ -603,9 +603,9 @@ class PromotionService
         $data     = ['log_id' => intval($logId)];
 
         if ($delay > 0) {
-            Queue::later($delay, $jobClass, $data, 'promotionmmm');
+            Queue::later($delay, $jobClass, $data, 'PromotionPrepareEmail');
         } else {
-            Queue::push($jobClass, $data, 'promotionmmm');
+            Queue::push($jobClass, $data, 'PromotionPrepareEmail');
         }
     }