diff --git a/src/core/assembler.ts b/src/core/assembler.ts
index 22dd300..9ed6c1f 100644
--- a/src/core/assembler.ts
+++ b/src/core/assembler.ts
@@ -4,7 +4,7 @@ import { join } from "node:path";
 import type { RuneConfig } from "../types.ts";
 import { CommandError } from "../cli/errors.ts";
 import { getChangeDir } from "./config.ts";
-import { parseTasks, validateTaskFormat } from "./task-parser.ts";
+import { parseTasks, validateTaskFormat, TaskFormatError } from "./task-parser.ts";
 import { applyCommandPrefix, getPmPrefix } from "./pm.ts";
 
 export function assembleDiscussPrompt(config: RuneConfig): string {
@@ -100,7 +100,16 @@ export async function assembleBuildPrompt(
     });
   }
 
-  validateTaskFormat(taskContent);
+  try {
+    validateTaskFormat(taskContent);
+  } catch (e) {
+    if (e instanceof TaskFormatError) {
+      throw new CommandError(e.message, {
+        hint: `请确保 ${taskPath} 中包含格式正确的 checkbox 任务项（如 - [ ] 任务描述）`,
+      });
+    }
+    throw e;
+  }
 
   const tasks = parseTasks(taskContent);
   const pendingTasks = tasks.filter((t) => !t.checked);
diff --git a/tests/core/assembler.test.ts b/tests/core/assembler.test.ts
index 936e7b9..e281c20 100644
--- a/tests/core/assembler.test.ts
+++ b/tests/core/assembler.test.ts
@@ -179,6 +179,7 @@ describe("assembleBuildPrompt", () => {
     } catch (e: any) {
       expect(e.message).toContain("task.md");
       expect(e.message).toContain("checkbox");
+      expect(e.hint).toBeTruthy();
     }
   });
 
@@ -195,6 +196,7 @@ describe("assembleBuildPrompt", () => {
       expect.unreachable();
     } catch (e: any) {
       expect(e.message).toContain("checkbox");
+      expect(e.hint).toBeTruthy();
     }
   });
 });