ty checking

src/personal_mcp/skills/document_loader.py

@@ -7,7 +7,9 @@ from typing import Any
 
 import yaml
 
+from ..registry.models.common import SKILL_ID_RE
 from ..registry.models.common import ReferenceEntry
+from ..registry.models.prompt import PromptFrontmatter
 from ..registry.models.skill import SkillFrontmatter
 
 
@@ -32,15 +34,16 @@ def _parse_frontmatter(markdown: str, *, path: str) -> tuple[dict[str, Any], str
     body = "\n".join(lines[end_index + 1 :])
     parsed = yaml.safe_load(raw_yaml)
     if not isinstance(parsed, dict):
-        raise ValueError(f"frontmatter must parse to an object: {path}")
+        raise TypeError(f"frontmatter must parse to an object: {path}")
     return parsed, body
 
 
 def _walk_markdown(
     node: Traversable,
     *,
-    prefix: PurePosixPath = PurePosixPath(),
+    prefix: PurePosixPath | None = None,
 ) -> list[tuple[str, Traversable]]:
+    prefix = PurePosixPath() if prefix is None else prefix
     results: list[tuple[str, Traversable]] = []
     for child in sorted(node.iterdir(), key=lambda item: item.name):
         relpath = prefix.joinpath(child.name)