fix: resolve SKILL.md validation errors

skills/api-patterns/SKILL.md

@@ -2,6 +2,8 @@
 name: api-patterns
 description: "API design principles and decision-making. REST vs GraphQL vs tRPC selection, response formats, versioning, pagination."
 allowed-tools: Read, Write, Edit, Glob, Grep
+risk: unknown
+source: community
 ---
 
 # API Patterns
@@ -79,3 +81,6 @@ Before designing an API:
 |--------|---------|---------|
 | `scripts/api_validator.py` | API endpoint validation | `python scripts/api_validator.py <project_path>` |
 
+
+## When to Use
+This skill is applicable to execute the workflow or actions described in the overview.