diff --git a/best-practice/claude-skills.md b/best-practice/claude-skills.md
index 4a57184..dc5c749 100644
--- a/best-practice/claude-skills.md
+++ b/best-practice/claude-skills.md
@@ -1,6 +1,6 @@
# Skills Best Practice
- 
+ 
[](../implementation/claude-skills-implementation.md)
Claude Code skills — frontmatter fields and official bundled skills.
@@ -14,12 +14,13 @@ Claude Code skills — frontmatter fields and official bundled skills.
---
-## Frontmatter Fields (13)
+## Frontmatter Fields (14)
| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `name` | string | No | Display name and `/slash-command` identifier. Defaults to the directory name if omitted |
| `description` | string | Recommended | What the skill does. Shown in autocomplete and used by Claude for auto-discovery |
+| `when_to_use` | string | No | Additional context for when Claude should invoke the skill — trigger phrases and example requests. Appended to `description` in the skill listing, counts toward the 1,536-character cap |
| `argument-hint` | string | No | Hint shown during autocomplete (e.g., `[issue-number]`, `[filename]`) |
| `disable-model-invocation` | boolean | No | Set `true` to prevent Claude from automatically invoking this skill |
| `user-invocable` | boolean | No | Set `false` to hide from the `/` menu — skill becomes background knowledge only, intended for agent preloading |