diff --git a/app/Module/AiTaskSuggestion.php b/app/Module/AiTaskSuggestion.php
new file mode 100644
index 000000000..2e37427fd
--- /dev/null
+++ b/app/Module/AiTaskSuggestion.php
@@ -0,0 +1,587 @@
+<?php
+
+namespace App\Module;
+
+use App\Models\ProjectTask;
+use App\Models\ProjectTaskAiEvent;
+use App\Models\ProjectTaskUser;
+use App\Models\ProjectUser;
+use App\Models\User;
+use App\Models\WebSocketDialogMsg;
+use Cache;
+use Carbon\Carbon;
+
+class AiTaskSuggestion
+{
+    /**
+     * AI 助手的 userid
+     */
+    const AI_ASSISTANT_USERID = -1;
+
+    /**
+     * 相似度阈值
+     */
+    const SIMILAR_THRESHOLD = 0.7;
+
+    /**
+     * 检查是否满足执行条件
+     */
+    public static function shouldExecute(ProjectTask $task, string $eventType): bool
+    {
+        switch ($eventType) {
+            case ProjectTaskAiEvent::EVENT_DESCRIPTION:
+                // 描述为空或长度 < 20
+                $content = trim($task->content ?? '');
+                return empty($content) || mb_strlen($content) < 20;
+
+            case ProjectTaskAiEvent::EVENT_SUBTASKS:
+                // 无子任务且标题长度 > 10
+                $hasSubtasks = ProjectTask::where('parent_id', $task->id)->exists();
+                return !$hasSubtasks && mb_strlen($task->name) > 10;
+
+            case ProjectTaskAiEvent::EVENT_ASSIGNEE:
+                // 未指定负责人
+                $hasOwner = ProjectTaskUser::where('task_id', $task->id)
+                    ->where('owner', 1)
+                    ->exists();
+                return !$hasOwner;
+
+            case ProjectTaskAiEvent::EVENT_SIMILAR:
+                // 始终执行
+                return true;
+
+            default:
+                return false;
+        }
+    }
+
+    /**
+     * 生成任务描述建议
+     */
+    public static function generateDescription(ProjectTask $task): ?array
+    {
+        $prompt = self::buildDescriptionPrompt($task);
+        $result = self::callAi($prompt);
+
+        if (empty($result)) {
+            return null;
+        }
+
+        return [
+            'type' => 'description',
+            'content' => $result,
+        ];
+    }
+
+    /**
+     * 生成子任务拆分建议
+     */
+    public static function generateSubtasks(ProjectTask $task): ?array
+    {
+        $prompt = self::buildSubtasksPrompt($task);
+        $result = self::callAi($prompt);
+
+        if (empty($result)) {
+            return null;
+        }
+
+        // 解析返回的子任务列表
+        $subtasks = self::parseSubtasksList($result);
+        if (empty($subtasks)) {
+            return null;
+        }
+
+        return [
+            'type' => 'subtasks',
+            'content' => $subtasks,
+        ];
+    }
+
+    /**
+     * 生成负责人推荐
+     */
+    public static function generateAssignee(ProjectTask $task): ?array
+    {
+        // 获取项目成员
+        $members = self::getProjectMembersInfo($task->project_id);
+        if (empty($members)) {
+            return null;
+        }
+
+        $prompt = self::buildAssigneePrompt($task, $members);
+        $result = self::callAi($prompt);
+
+        if (empty($result)) {
+            return null;
+        }
+
+        // 解析推荐结果
+        $recommendations = self::parseAssigneeRecommendations($result, $members);
+        if (empty($recommendations)) {
+            return null;
+        }
+
+        return [
+            'type' => 'assignee',
+            'content' => $recommendations,
+        ];
+    }
+
+    /**
+     * 搜索相似任务
+     */
+    public static function findSimilarTasks(ProjectTask $task): ?array
+    {
+        // 使用 AI 模块的 Embedding 搜索
+        $searchText = $task->name . ' ' . ($task->content ?? '');
+
+        try {
+            $embedding = AI::getEmbedding($searchText);
+            if (empty($embedding)) {
+                return null;
+            }
+
+            // 搜索相似任务（排除自己和子任务）
+            $similarTasks = self::searchSimilarByEmbedding(
+                $embedding,
+                $task->project_id,
+                $task->id
+            );
+
+            if (empty($similarTasks)) {
+                return null;
+            }
+
+            return [
+                'type' => 'similar',
+                'content' => $similarTasks,
+            ];
+        } catch (\Exception $e) {
+            \Log::error('AiTaskSuggestion::findSimilarTasks error: ' . $e->getMessage());
+            return null;
+        }
+    }
+
+    /**
+     * 构建描述生成 Prompt
+     */
+    private static function buildDescriptionPrompt(ProjectTask $task): string
+    {
+        $projectName = $task->project->name ?? '未知项目';
+
+        return <<<PROMPT
+你是一个专业的项目管理助手。请根据以下任务标题，生成结构化的任务描述。
+
+任务标题：{$task->name}
+所属项目：{$projectName}
+
+请按以下格式生成任务描述（使用 Markdown）：
+
+> **背景**：[描述任务的背景和上下文]
+> **目标**：[明确任务要达成的目标]
+> **验收标准**：
+> - [验收标准1]
+> - [验收标准2]
+> - [验收标准3]
+
+要求：
+1. 内容要专业、简洁
+2. 验收标准要具体、可衡量
+3. 与用户输入语言保持一致
+PROMPT;
+    }
+
+    /**
+     * 构建子任务拆分 Prompt
+     */
+    private static function buildSubtasksPrompt(ProjectTask $task): string
+    {
+        $content = $task->content ?? '';
+
+        return <<<PROMPT
+你是一个专业的项目管理助手。请将以下任务拆分为可执行的子任务。
+
+任务标题：{$task->name}
+任务描述：{$content}
+
+请返回 3-5 个子任务，每行一个，格式如下：
+1. [子任务名称]
+2. [子任务名称]
+...
+
+要求：
+1. 每个子任务要具体、可执行
+2. 子任务之间有合理的顺序
+3. 子任务名称简洁明了（不超过30字）
+4. 只返回子任务列表，不要其他内容
+PROMPT;
+    }
+
+    /**
+     * 构建负责人推荐 Prompt
+     */
+    private static function buildAssigneePrompt(ProjectTask $task, array $members): string
+    {
+        $membersText = '';
+        foreach ($members as $member) {
+            $membersText .= "- {$member['nickname']}（ID:{$member['userid']}）";
+            if (!empty($member['profession'])) {
+                $membersText .= "，职位：{$member['profession']}";
+            }
+            $membersText .= "，进行中任务：{$member['in_progress_count']}个";
+            $membersText .= "，近期完成：{$member['completed_count']}个";
+            if ($member['similar_count'] > 0) {
+                $membersText .= "，处理过类似任务：{$member['similar_count']}个";
+            }
+            $membersText .= "\n";
+        }
+
+        return <<<PROMPT
+你是一个专业的项目管理助手。请根据任务内容和团队成员情况，推荐最合适的负责人。
+
+任务标题：{$task->name}
+任务描述：{$task->content}
+
+团队成员：
+{$membersText}
+
+请推荐 2 名最合适的负责人，按优先级排序，格式如下：
+1. [userid]|[推荐理由，简短说明]
+2. [userid]|[推荐理由，简短说明]
+
+推荐依据：
+1. 优先选择处理过类似任务的成员
+2. 考虑当前工作负载（进行中任务较少的优先）
+3. 考虑专业匹配度
+
+只返回推荐列表，不要其他内容。
+PROMPT;
+    }
+
+    /**
+     * 调用 AI 接口
+     */
+    private static function callAi(string $prompt): ?string
+    {
+        try {
+            // 使用 AI 模块调用
+            $result = AI::invoke([
+                ['system', '你是 DooTask 任务管理系统的 AI 助手，帮助用户管理任务。'],
+                ['user', $prompt],
+            ]);
+
+            return $result['content'] ?? null;
+        } catch (\Exception $e) {
+            \Log::error('AiTaskSuggestion::callAi error: ' . $e->getMessage());
+            return null;
+        }
+    }
+
+    /**
+     * 获取项目成员信息
+     */
+    private static function getProjectMembersInfo(int $projectId): array
+    {
+        $projectUsers = ProjectUser::where('project_id', $projectId)->get();
+        $members = [];
+
+        foreach ($projectUsers as $pu) {
+            $user = User::find($pu->userid);
+            if (!$user || $user->bot || $user->disable_at) {
+                continue;
+            }
+
+            // 获取进行中任务数量
+            $inProgressCount = ProjectTask::join('project_task_users', 'project_tasks.id', '=', 'project_task_users.task_id')
+                ->where('project_task_users.userid', $user->userid)
+                ->whereNull('project_tasks.complete_at')
+                ->whereNull('project_tasks.archived_at')
+                ->whereNull('project_tasks.deleted_at')
+                ->count();
+
+            // 获取近期完成任务数量
+            $completedCount = ProjectTask::join('project_task_users', 'project_tasks.id', '=', 'project_task_users.task_id')
+                ->where('project_task_users.userid', $user->userid)
+                ->whereNotNull('project_tasks.complete_at')
+                ->where('project_tasks.complete_at', '>=', Carbon::now()->subDays(30))
+                ->whereNull('project_tasks.deleted_at')
+                ->count();
+
+            $members[] = [
+                'userid' => $user->userid,
+                'nickname' => $user->nickname,
+                'profession' => $user->profession ?? '',
+                'in_progress_count' => $inProgressCount,
+                'completed_count' => $completedCount,
+                'similar_count' => 0, // TODO: 计算相似任务数量
+            ];
+        }
+
+        return $members;
+    }
+
+    /**
+     * 解析子任务列表
+     */
+    private static function parseSubtasksList(string $text): array
+    {
+        $lines = explode("\n", trim($text));
+        $subtasks = [];
+
+        foreach ($lines as $line) {
+            $line = trim($line);
+            // 移除序号前缀
+            $line = preg_replace('/^\d+[\.\)、]\s*/', '', $line);
+            if (!empty($line) && mb_strlen($line) <= 100) {
+                $subtasks[] = $line;
+            }
+        }
+
+        return array_slice($subtasks, 0, 5); // 最多5个
+    }
+
+    /**
+     * 解析负责人推荐结果
+     */
+    private static function parseAssigneeRecommendations(string $text, array $members): array
+    {
+        $memberMap = [];
+        foreach ($members as $m) {
+            $memberMap[$m['userid']] = $m;
+        }
+
+        $lines = explode("\n", trim($text));
+        $recommendations = [];
+
+        foreach ($lines as $line) {
+            $line = trim($line);
+            $line = preg_replace('/^\d+[\.\)、]\s*/', '', $line);
+
+            if (preg_match('/^(\d+)\|(.+)$/', $line, $matches)) {
+                $userid = intval($matches[1]);
+                $reason = trim($matches[2]);
+
+                if (isset($memberMap[$userid])) {
+                    $recommendations[] = [
+                        'userid' => $userid,
+                        'nickname' => $memberMap[$userid]['nickname'],
+                        'reason' => $reason,
+                    ];
+                }
+            }
+        }
+
+        return array_slice($recommendations, 0, 2); // 最多2个
+    }
+
+    /**
+     * 通过 Embedding 搜索相似任务
+     */
+    private static function searchSimilarByEmbedding(array $embedding, int $projectId, int $excludeTaskId): array
+    {
+        // TODO: 实现向量搜索
+        // 当前先返回空数组，后续集成 SeekDB 或其他向量搜索
+        return [];
+    }
+
+    /**
+     * 构建 Markdown 消息
+     */
+    public static function buildMarkdownMessage(int $taskId, array $suggestions, int $msgId = 0): string
+    {
+        $parts = ["## AI 任务建议\n"];
+
+        foreach ($suggestions as $suggestion) {
+            switch ($suggestion['type']) {
+                case 'description':
+                    $parts[] = self::buildDescriptionMarkdown($taskId, $msgId, $suggestion['content']);
+                    break;
+                case 'subtasks':
+                    $parts[] = self::buildSubtasksMarkdown($taskId, $msgId, $suggestion['content']);
+                    break;
+                case 'assignee':
+                    $parts[] = self::buildAssigneeMarkdown($taskId, $msgId, $suggestion['content']);
+                    break;
+                case 'similar':
+                    $parts[] = self::buildSimilarMarkdown($taskId, $msgId, $suggestion['content']);
+                    break;
+            }
+        }
+
+        return implode("\n---\n\n", $parts);
+    }
+
+    /**
+     * 构建描述建议 Markdown
+     */
+    private static function buildDescriptionMarkdown(int $taskId, int $msgId, string $content): string
+    {
+        $applyUrl = "dootask://ai-apply/description/{$taskId}/{$msgId}";
+        $dismissUrl = "dootask://ai-dismiss/description/{$taskId}/{$msgId}";
+
+        return <<<MD
+### 建议补充任务描述
+
+{$content}
+
+[✓ 采纳描述]({$applyUrl})  [✗ 忽略]({$dismissUrl})
+MD;
+    }
+
+    /**
+     * 构建子任务建议 Markdown
+     */
+    private static function buildSubtasksMarkdown(int $taskId, int $msgId, array $subtasks): string
+    {
+        $list = '';
+        foreach ($subtasks as $i => $name) {
+            $num = $i + 1;
+            $list .= "{$num}. {$name}\n";
+        }
+
+        $applyUrl = "dootask://ai-apply/subtasks/{$taskId}/{$msgId}";
+        $dismissUrl = "dootask://ai-dismiss/subtasks/{$taskId}/{$msgId}";
+
+        return <<<MD
+### 建议拆分子任务
+
+{$list}
+[✓ 创建子任务]({$applyUrl})  [✗ 忽略]({$dismissUrl})
+MD;
+    }
+
+    /**
+     * 构建负责人建议 Markdown
+     */
+    private static function buildAssigneeMarkdown(int $taskId, int $msgId, array $recommendations): string
+    {
+        $list = '';
+        $buttons = '';
+        foreach ($recommendations as $rec) {
+            $list .= "- **{$rec['nickname']}** - {$rec['reason']}\n";
+            $applyUrl = "dootask://ai-apply/assignee/{$taskId}/{$msgId}?userid={$rec['userid']}";
+            $buttons .= "[指派给{$rec['nickname']}]({$applyUrl})  ";
+        }
+
+        return <<<MD
+### 推荐负责人
+
+{$list}
+{$buttons}
+MD;
+    }
+
+    /**
+     * 构建相似任务 Markdown
+     */
+    private static function buildSimilarMarkdown(int $taskId, int $msgId, array $similarTasks): string
+    {
+        $list = '';
+        foreach ($similarTasks as $i => $st) {
+            $num = $i + 1;
+            $viewUrl = "dootask://task/{$st['id']}";
+            $addUrl = "dootask://ai-apply/similar/{$taskId}/{$msgId}?related={$st['id']}";
+            $similarity = round($st['similarity'] * 100);
+            $list .= "{$num}. **#{$st['id']} {$st['name']}** - 相似度 {$similarity}%\n";
+            $list .= "   [查看任务]({$viewUrl})  [添加关联]({$addUrl})\n\n";
+        }
+
+        $dismissUrl = "dootask://ai-dismiss/similar/{$taskId}/{$msgId}";
+
+        return <<<MD
+### 发现相似任务
+
+以下任务与当前任务内容相似，可能是重复任务或可作为参考：
+
+{$list}
+[全部忽略]({$dismissUrl})
+MD;
+    }
+
+    /**
+     * 发送建议消息
+     */
+    public static function sendSuggestionMessage(ProjectTask $task, array $suggestions): ?int
+    {
+        if (empty($suggestions) || empty($task->dialog_id)) {
+            return null;
+        }
+
+        // 先发送消息获取 msg_id，然后更新消息内容带上 msg_id
+        $tempMarkdown = self::buildMarkdownMessage($task->id, $suggestions, 0);
+
+        $result = WebSocketDialogMsg::sendMsg(
+            null,
+            $task->dialog_id,
+            'text',
+            ['text' => $tempMarkdown, 'type' => 'md'],
+            self::AI_ASSISTANT_USERID,
+            true,  // push_self
+            false, // push_retry
+            true   // push_silence
+        );
+
+        if (Base::isSuccess($result)) {
+            $msgId = $result['data']->id ?? 0;
+            if ($msgId > 0) {
+                // 更新消息，带上真实的 msg_id
+                $finalMarkdown = self::buildMarkdownMessage($task->id, $suggestions, $msgId);
+                WebSocketDialogMsg::sendMsg(
+                    'change-' . $msgId,
+                    $task->dialog_id,
+                    'text',
+                    ['text' => $finalMarkdown, 'type' => 'md'],
+                    self::AI_ASSISTANT_USERID
+                );
+                return $msgId;
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * 更新消息状态（采纳/忽略后）
+     */
+    public static function updateMessageStatus(int $msgId, int $dialogId, string $type, string $status): void
+    {
+        $msg = WebSocketDialogMsg::find($msgId);
+        if (!$msg) {
+            return;
+        }
+
+        $content = $msg->msg['text'] ?? '';
+        if (empty($content)) {
+            return;
+        }
+
+        // 根据状态替换对应的按钮
+        $statusText = $status === 'applied' ? '✓ 已采纳' : '✗ 已忽略';
+
+        // 替换对应类型的按钮为状态文字
+        $pattern = '/\[.*?\]\(dootask:\/\/ai-(apply|dismiss)\/' . preg_quote($type, '/') . '\/\d+\/\d+[^)]*\)\s*/';
+        $newContent = preg_replace($pattern, '', $content);
+
+        // 在对应标题后添加状态
+        $sectionTitles = [
+            'description' => '### 建议补充任务描述',
+            'subtasks' => '### 建议拆分子任务',
+            'assignee' => '### 推荐负责人',
+            'similar' => '### 发现相似任务',
+        ];
+
+        if (isset($sectionTitles[$type])) {
+            $title = $sectionTitles[$type];
+            $newContent = str_replace($title, $title . "\n\n**{$statusText}**", $newContent);
+        }
+
+        // 更新消息
+        WebSocketDialogMsg::sendMsg(
+            'change-' . $msgId,
+            $dialogId,
+            'text',
+            ['text' => $newContent, 'type' => 'md'],
+            self::AI_ASSISTANT_USERID
+        );
+    }
+}