IDE validator rejects officially supported skill frontmatter attributes (context, agent, etc.)

Bug Description

The IDE diagnostic validator for skill files (SKILL.md) rejects several frontmatter attributes that are officially documented as supported.

Steps to Reproduce

1. Create a skill file .claude/skills/my-skill/SKILL.md
2. Add context: fork and agent: Explore to the frontmatter:

---
name: my-skill
description: "Test skill"
user-invocable: true
context: fork
agent: Explore
---

1. IDE shows warnings:

⚠ Attribute 'context' is not supported in skill files.
  Supported: argument-hint, compatibility, description, disable-model-invocation,
  license, metadata, name, user-invocable.
⚠ Attribute 'agent' is not supported in skill files.
  Supported: argument-hint, compatibility, description, disable-model-invocation,
  license, metadata, name, user-invocable.

Expected Behavior

No warnings — these attributes are documented as supported in the official Skills documentation.

Affected Attributes

| Attribute | Docs say supported | IDE validator |
|-----------|-------------------|---------------|
| context | ✅ Yes | ❌ Rejected |
| agent | ✅ Yes | ❌ Rejected |
| allowed-tools | ✅ Yes | ❌ Not in allowed list |
| model | ✅ Yes | ❌ Not in allowed list |
| effort | ✅ Yes | ❌ Not in allowed list |
| hooks | ✅ Yes | ❌ Not in allowed list |
| paths | ✅ Yes | ❌ Not in allowed list |
| shell | ✅ Yes | ❌ Not in allowed list |

The validator only recognizes 8 attributes: argument-hint, compatibility, description, disable-model-invocation, license, metadata, name, user-invocable.

Environment

• Claude Code CLI (VS Code extension)
• macOS Darwin 25.3.0
• Model: claude-opus-4-6

🤖 Generated with Claude Code