diff --git a/src-tauri/src/commands/module.rs b/src-tauri/src/commands/module.rs
index 1fafe97..7badeeb 100644
--- a/src-tauri/src/commands/module.rs
+++ b/src-tauri/src/commands/module.rs
@@ -1198,3 +1198,72 @@ pub async fn list_module_dependencies(
         .await
         .map_err(err_str)
 }
+
+/// 检测工程依赖图中的环形依赖(DFS 三色标记法)。
+/// 返回参与环的 module_id 列表(空 = 无环)。
+#[tauri::command]
+pub async fn detect_module_cycles(
+    state: State<'_, AppState>,
+    project_id: String,
+) -> Result<Vec<String>, String> {
+    let project_id = project_id.trim().to_string();
+    if project_id.is_empty() {
+        return Err("project_id 不能为空".to_string());
+    }
+    let deps = state
+        .module_dependencies
+        .list_by_field("project_id", &project_id)
+        .await
+        .map_err(err_str)?;
+    // 构建邻接表
+    let mut adj: std::collections::HashMap<String, Vec<String>> = std::collections::HashMap::new();
+    for d in &deps {
+        adj.entry(d.from_module_id.clone())
+            .or_default()
+            .push(d.to_module_id.clone());
+        adj.entry(d.to_module_id.clone()).or_default();
+    }
+    // DFS 三色:0=白(未访问) 1=灰(栈中) 2=黑(完成)
+    let mut color: std::collections::HashMap<String, u8> = std::collections::HashMap::new();
+    let mut cycle_nodes: std::collections::HashSet<String> = std::collections::HashSet::new();
+    fn dfs(
+        node: &str,
+        adj: &std::collections::HashMap<String, Vec<String>>,
+        color: &mut std::collections::HashMap<String, u8>,
+        cycle_nodes: &mut std::collections::HashSet<String>,
+        path: &mut Vec<String>,
+    ) {
+        let c = color.get(node).copied().unwrap_or(0);
+        if c == 1 {
+            // 发现环:path 中从当前节点开始的都参与环
+            let in_cycle = path.iter().position(|n| n == node);
+            if let Some(start) = in_cycle {
+                for n in &path[start..] {
+                    cycle_nodes.insert(n.clone());
+                }
+            }
+            cycle_nodes.insert(node.to_string());
+            return;
+        }
+        if c == 2 {
+            return;
+        }
+        color.insert(node.to_string(), 1);
+        path.push(node.to_string());
+        if let Some(neighbors) = adj.get(node) {
+            for next in neighbors {
+                dfs(next, adj, color, cycle_nodes, path);
+            }
+        }
+        path.pop();
+        color.insert(node.to_string(), 2);
+    }
+    let nodes: Vec<String> = adj.keys().cloned().collect();
+    let mut path: Vec<String> = Vec::new();
+    for n in &nodes {
+        if color.get(n).copied().unwrap_or(0) == 0 {
+            dfs(n, &adj, &mut color, &mut cycle_nodes, &mut path);
+        }
+    }
+    Ok(cycle_nodes.into_iter().collect())
+}
diff --git a/src-tauri/src/commands/task.rs b/src-tauri/src/commands/task.rs
index c6d5446..aa91234 100644
--- a/src-tauri/src/commands/task.rs
+++ b/src-tauri/src/commands/task.rs
@@ -203,6 +203,16 @@ pub async fn list_tasks(
     Ok(tasks)
 }
 
+/// 按条件计数任务(分页 total 用)。
+#[tauri::command]
+pub async fn count_tasks(
+    state: State<'_, AppState>,
+    query: Option<TaskQuery>,
+) -> Result<i64, String> {
+    let q = query.unwrap_or_default();
+    state.tasks.count_by_query(&q).await.map_err(err_str)
+}
+
 /// 按 id 查任务，找不到返回 Err(供前端详情页)
 #[tauri::command]
 pub async fn get_task_by_id(
diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index e7590f4..e3f0ce2 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -300,6 +300,7 @@ pub fn run() {
             commands::project::import_projects_batch,
             // 任务
             commands::task::list_tasks,
+            commands::task::count_tasks,
             commands::task::create_task,
             commands::task::update_task,
             commands::task::delete_task,
@@ -337,6 +338,7 @@ pub fn run() {
             commands::module::add_module_dependency,
             commands::module::remove_module_dependency,
             commands::module::list_module_dependencies,
+            commands::module::detect_module_cycles,
             // 灵感
             commands::idea::list_ideas,
             commands::idea::create_idea,
diff --git a/src/api/module.ts b/src/api/module.ts
index a5b9caa..d26b9db 100644
--- a/src/api/module.ts
+++ b/src/api/module.ts
@@ -168,6 +168,11 @@ export const moduleApi = {
     return invoke('list_branches', { moduleId })
   },
 
+  /** 检测工程依赖环形依赖,返回参与环的 module_id 列表(空=无环)。 */
+  detectModuleCycles(projectId: string): Promise<string[]> {
+    return invoke('detect_module_cycles', { projectId })
+  },
+
   /** 列出项目全部工程依赖。 */
   listModuleDependencies(projectId: string): Promise<ModuleDependencyRecord[]> {
     return invoke('list_module_dependencies', { projectId })
diff --git a/src/api/task.ts b/src/api/task.ts
index 7932225..8e66990 100644
--- a/src/api/task.ts
+++ b/src/api/task.ts
@@ -18,6 +18,11 @@ export const taskApi = {
     return invoke('list_tasks', { projectId: null, query: queryOrProjectId ?? null })
   },
 
+  /** 按条件计数任务(分页 total 用)。 */
+  count(query?: TaskQuery): Promise<number> {
+    return invoke('count_tasks', { query: query ?? null })
+  },
+
   get(id: string): Promise<TaskRecord> {
     return invoke('get_task_by_id', { id })
   },
diff --git a/src/components/project/DependencyGraph.vue b/src/components/project/DependencyGraph.vue
index bdfba8f..2942b1a 100644
--- a/src/components/project/DependencyGraph.vue
+++ b/src/components/project/DependencyGraph.vue
@@ -4,6 +4,8 @@
       <span class="dep-graph__title">{{ $t('dependencyGraph.title') }}</span>
       <div class="dep-graph__actions">
         <button v-if="modules.length >= 2" class="btn btn-ghost btn-sm" @click="showAddDep = true">+ 依赖</button>
+        <button v-if="dependencies.length > 0" class="btn btn-ghost btn-sm" @click="checkCycles">🔍 环检测</button>
+        <button class="btn btn-ghost btn-sm" @click="exportPNG">📷 导出</button>
         <button class="btn btn-ghost btn-sm" @click="fitContent">适应内容</button>
         <button class="btn btn-ghost btn-sm" @click="zoomIn">+</button>
         <button class="btn btn-ghost btn-sm" @click="zoomOut">-</button>
@@ -211,6 +213,43 @@ function zoomOut() {
   graph?.zoom(-0.1)
 }
 
+/** 环形依赖检测。 */
+const cycleNodes = ref<Set<string>>(new Set())
+async function checkCycles() {
+  try {
+    const cycles = await moduleApi.detectModuleCycles(props.projectId)
+    cycleNodes.value = new Set(cycles)
+    if (cycles.length > 0) {
+      // 高亮环节点(加红色边框)
+      for (const id of cycles) {
+        const cell = graph?.getCellById(id)
+        if (cell) {
+          cell.attr('body/stroke', '#e05050')
+          cell.attr('body/strokeWidth', 3)
+        }
+      }
+    }
+    renderGraph()
+  } catch (e) {
+    console.error('[DependencyGraph] 环检测失败:', e)
+  }
+}
+
+/** 导出 PNG。 */
+async function exportPNG() {
+  if (!graph) return
+  try {
+    graph.toPNG((dataUri: string) => {
+      const a = document.createElement('a')
+      a.href = dataUri
+      a.download = `dependency-graph-${props.projectId}.png`
+      a.click()
+    })
+  } catch (e) {
+    console.error('[DependencyGraph] 导出 PNG 失败:', e)
+  }
+}
+
 /** 依赖类型 → 边颜色 */
 function depTypeColor(depType: string): string {
   switch (depType) {
diff --git a/src/views/Tasks.vue b/src/views/Tasks.vue
index 99c9234..865d812 100644
--- a/src/views/Tasks.vue
+++ b/src/views/Tasks.vue
@@ -252,7 +252,10 @@ watch(searchKeyword, () => {
   _searchTimer = setTimeout(() => {
     page.value = 1
     loading.value = true
-    store.loadTasks(buildTaskQuery()).finally(() => { loading.value = false })
+    Promise.all([
+      store.loadTasks(buildTaskQuery()),
+      taskApi.count(buildTaskQuery()).then(n => totalTasks.value = n),
+    ]).finally(() => { loading.value = false })
   }, 300)
 })
 
@@ -383,20 +386,29 @@ watch(activeProject, () => {
   store.setActiveTaskProject(activeProject.value)
   page.value = 1
   loading.value = true
-  store.loadTasks(buildTaskQuery()).finally(() => { loading.value = false })
+  Promise.all([
+    store.loadTasks(buildTaskQuery()),
+    taskApi.count(buildTaskQuery()).then(n => totalTasks.value = n),
+  ]).finally(() => { loading.value = false })
 })
 
 watch(activeStatus, () => {
   store.setActiveTaskStatus(activeStatus.value)
   page.value = 1
   loading.value = true
-  store.loadTasks(buildTaskQuery()).finally(() => { loading.value = false })
+  Promise.all([
+    store.loadTasks(buildTaskQuery()),
+    taskApi.count(buildTaskQuery()).then(n => totalTasks.value = n),
+  ]).finally(() => { loading.value = false })
 })
 
 watch(sortBy, () => {
   page.value = 1
   loading.value = true
-  store.loadTasks(buildTaskQuery()).finally(() => { loading.value = false })
+  Promise.all([
+    store.loadTasks(buildTaskQuery()),
+    taskApi.count(buildTaskQuery()).then(n => totalTasks.value = n),
+  ]).finally(() => { loading.value = false })
 })
 
 // Ctrl+N 新建 / Ctrl+F 搜索(桌面快捷键)
@@ -415,7 +427,11 @@ onMounted(async () => {
   store.setActiveTaskStatus(activeStatus.value)
   loading.value = true
   try {
-    await Promise.all([store.loadProjects(), store.loadTasks()])
+    await Promise.all([
+      store.loadProjects(),
+      store.loadTasks(),
+      taskApi.count().then(n => totalTasks.value = n),
+    ])
   } finally {
     loading.value = false
   }