diff --git a/pipeline_core/skill_loader.py b/pipeline_core/skill_loader.py
index 6a51481..d8124d6 100644
--- a/pipeline_core/skill_loader.py
+++ b/pipeline_core/skill_loader.py
@@ -66,6 +66,7 @@ class Skill:
     version: str = "1.0.0"
     capability: str = ""             # 配套能力名（如 task_capability / communication）
     tools: List[str] = field(default_factory=list)   # 配套工具名列表
+    essential: bool = False          # 基础规范：所有角色目录层必显示（如 project-directory-spec）
 
     @classmethod
     def from_file(cls, filepath: str, scope: str = "global",
@@ -77,6 +78,7 @@ class Skill:
         version = "1.0.0"
         capability = ""
         tools = []
+        essential = False
 
         try:
             with open(filepath, "r", encoding="utf-8") as f:
@@ -93,6 +95,7 @@ class Skill:
             scope = fm.get("scope", scope)
             capability = fm.get("capability", "") or ""
             tools = fm.get("tools", []) or []
+            essential = str(fm.get("essential", "")).lower() in ("true", "1", "yes")
 
         if not description:
             for line in content.split("\n"):
@@ -105,7 +108,7 @@ class Skill:
             name=name, path=filepath, description=description,
             content=content, scope=scope, scope_id=scope_id,
             trigger_keywords=trigger_keywords, version=version,
-            capability=capability, tools=tools,
+            capability=capability, tools=tools, essential=essential,
         )
 
     def to_prompt_block(self) -> str:
diff --git a/skills_library/all/project-directory-spec/SKILL.md b/skills_library/all/project-directory-spec/SKILL.md
index d989585..e4ae837 100644
--- a/skills_library/all/project-directory-spec/SKILL.md
+++ b/skills_library/all/project-directory-spec/SKILL.md
@@ -1,6 +1,7 @@
 ---
 name: project-directory-spec
 description: 项目目录规范——项目工作空间目录结构与各目录作用（README.md 项目说明 + repos/ 下按 项目工程文档(_pc)/应用(_app)/独立模块 三类独立仓库组织）。所有 SDLC 角色产出与检查前必读，路径以此为准。
+essential: true
 ---
 
 # 项目目录规范