diff --git a/AGENTS.md b/AGENTS.md
new file mode 100644
index 0000000..e309083
--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,9 @@
+# AGENTS.md
+
+## 工作方式
+
+- 修复 bug 或添加新功能时，先在本机完成实现、编译和运行验证，不要把半成品直接交给服务器。
+- 优先使用仓库内的 Docker / Docker Compose 做构建和本地运行；如果本地环境缺依赖，也优先补齐本地容器化环境，而不是直接部署到服务器。
+- 只有在本地构建、测试和人工检查都完成后，才建议把代码推送到 Gitea，并提醒用户在服务器上拉取、重新构建或更新服务。
+- 没有用户明确确认，不要重启 Docker Desktop，也不要重启或更新线上服务。
+- 提交前至少跑通与改动直接相关的测试；涉及 Dockerfile / compose / 容器行为时，用本地 Docker 验证。
diff --git a/backend/service/app.py b/backend/service/app.py
index f252676..0742632 100644
--- a/backend/service/app.py
+++ b/backend/service/app.py
@@ -1399,6 +1399,26 @@ def _zip_asset_entry(zf: zipfile.ZipFile, pkg_id: str) -> str:
     return sorted(candidates)[0]
 
 
+def _asset_reference_names(asset_id: str) -> list[str]:
+    usages: list[str] = []
+    data_sources = (
+        (DESIGN_TEMPLATES_DIR, "template.json"),
+        (PROJECTS_DIR, "project.json"),
+    )
+    for root, filename in data_sources:
+        for item in _list_dirs(root):
+            path = item / filename
+            if not path.exists():
+                continue
+            try:
+                data = json.loads(path.read_text(encoding="utf-8"))
+            except Exception:
+                continue
+            if asset_id in json.dumps(data, ensure_ascii=False):
+                usages.append(str(data.get("name") or item.name))
+    return usages
+
+
 def _remap_import_asset_ids(document: dict, asset_map: dict[str, str]) -> None:
     elements = document.get("elements")
     if not isinstance(elements, list):
@@ -1796,6 +1816,10 @@ def delete_asset(asset_id: str) -> None:
     meta = _read_asset_meta(d)
     if not meta:
         raise HTTPException(status_code=404, detail="asset not found")
+    usages = _asset_reference_names(asset_id)
+    if usages:
+        names = "、".join(dict.fromkeys(usages))
+        raise HTTPException(status_code=409, detail=f"素材仍被以下设计引用，无法删除：{names}")
     shutil.rmtree(d, ignore_errors=True)
 
 
diff --git a/backend/tests/test_asset_delete_protection.py b/backend/tests/test_asset_delete_protection.py
new file mode 100644
index 0000000..b9b607e
--- /dev/null
+++ b/backend/tests/test_asset_delete_protection.py
@@ -0,0 +1,102 @@
+import json
+import sys
+from pathlib import Path
+
+import pytest
+
+
+BACKEND_DIR = Path(__file__).resolve().parents[1]
+if str(BACKEND_DIR) not in sys.path:
+    sys.path.insert(0, str(BACKEND_DIR))
+
+from fastapi import HTTPException  # noqa: E402
+from service import app  # noqa: E402
+
+
+SVG = '<svg xmlns="http://www.w3.org/2000/svg" width="20" height="10"/>'
+ASSET_ID = "asset_deleteprotected000000000000000000"
+
+
+@pytest.fixture
+def isolated_storage(tmp_path, monkeypatch):
+    assets_dir = tmp_path / "service_assets"
+    templates_dir = tmp_path / "service_design_templates"
+    projects_dir = tmp_path / "service_projects"
+    for directory in (assets_dir, templates_dir, projects_dir):
+        directory.mkdir()
+    monkeypatch.setattr(app, "ASSETS_DIR", assets_dir)
+    monkeypatch.setattr(app, "DESIGN_TEMPLATES_DIR", templates_dir)
+    monkeypatch.setattr(app, "PROJECTS_DIR", projects_dir)
+    return assets_dir
+
+
+def create_sticker_asset(assets_dir, asset_id=ASSET_ID):
+    asset_dir = assets_dir / asset_id[:2] / asset_id
+    asset_dir.mkdir(parents=True)
+    (asset_dir / "asset.svg").write_text(SVG, encoding="utf-8")
+    (asset_dir / "meta.json").write_text(
+        json.dumps(
+            {
+                "asset_id": asset_id,
+                "name": "protected sticker",
+                "type": "sticker",
+                "mime_type": "image/svg+xml",
+            }
+        ),
+        encoding="utf-8",
+    )
+
+
+def test_delete_asset_blocks_design_template_reference(isolated_storage):
+    create_sticker_asset(isolated_storage)
+    templates_dir = isolated_storage.parent / "service_design_templates"
+    template_dir = templates_dir / "tm" / "tmpl_test"
+    template_dir.mkdir(parents=True)
+    (template_dir / "template.json").write_text(
+        json.dumps(
+            {
+                "template_id": "tmpl_test",
+                "name": "TEST模板",
+                "document": {"elements": [{"type": "sticker", "assetId": ASSET_ID}]},
+            }
+        ),
+        encoding="utf-8",
+    )
+
+    with pytest.raises(HTTPException) as excinfo:
+        app.delete_asset(ASSET_ID)
+
+    assert excinfo.value.status_code == 409
+    assert "TEST模板" in str(excinfo.value.detail)
+    assert (isolated_storage / ASSET_ID[:2] / ASSET_ID / "meta.json").exists()
+
+
+def test_delete_asset_blocks_project_reference(isolated_storage):
+    create_sticker_asset(isolated_storage)
+    projects_dir = isolated_storage.parent / "service_projects"
+    project_dir = projects_dir / "pr" / "proj_test"
+    project_dir.mkdir(parents=True)
+    (project_dir / "project.json").write_text(
+        json.dumps(
+            {
+                "project_id": "proj_test",
+                "name": "生产项目",
+                "stickers": [{"assetId": ASSET_ID}],
+            }
+        ),
+        encoding="utf-8",
+    )
+
+    with pytest.raises(HTTPException) as excinfo:
+        app.delete_asset(ASSET_ID)
+
+    assert excinfo.value.status_code == 409
+    assert "生产项目" in str(excinfo.value.detail)
+
+
+def test_delete_asset_allows_unreferenced_sticker(isolated_storage):
+    create_sticker_asset(isolated_storage)
+
+    app.delete_asset(ASSET_ID)
+
+    assert not (isolated_storage / ASSET_ID[:2] / ASSET_ID).exists()