Tag Taxonomy

# Tag Taxonomy — Controlled Vocabulary for Wiki Tags

You are enforcing consistent tagging across the wiki by normalizing tags to a controlled vocabulary.

## Before You Start

1. **Resolve config** — follow the Config Resolution Protocol in `llm-wiki/SKILL.md` (walk up CWD for `.env` → `~/.obsidian-wiki/config` → prompt setup). This gives `OBSIDIAN_VAULT_PATH`
2. Read `$OBSIDIAN_VAULT_PATH/_meta/taxonomy.md` — this is the canonical tag list
3. Read `index.md` to understand the wiki's scope

## The Taxonomy File

The canonical tag vocabulary lives at `$OBSIDIAN_VAULT_PATH/_meta/taxonomy.md`. It defines:

- **Canonical tags** — the tags that should be used
- **Aliases** — common alternatives that should be mapped to the canonical form
- **Rules** — max 5 tags per page, lowercase/hyphenated, prefer broad over narrow
- **Migration guide** — specific renames for known inconsistencies

**Always read this file before tagging.** It's the source of truth.

## Reserved System Tags

`visibility/` is a reserved tag group with special rules. These tags are **not** domain or type tags and are managed separately from the taxonomy vocabulary:

| Tag | Purpose |
|---|---|
| `visibility/public` | Explicitly public — shown in all modes (same as no tag) |
| `visibility/internal` | Team-only — excluded in filtered query/export mode |
| `visibility/pii` | Sensitive data — excluded in filtered query/export mode |

**Rules for `visibility/` tags:**
- They do **not** count toward the 5-tag limit
- Only one `visibility/` tag per page
- Omit entirely when content is clearly public — no tag needed
- Never add `visibility/internal` just because content is technical; use it only for genuinely team-restricted knowledge
- When running a tag audit, report `visibility/` tag usage separately — do not flag them as unknown or non-canonical

When normalizing tags, leave `visibility/` tags untouched — they are not subject to alias mapping.

## Mode 1: Tag Audit

When the user wants to see the current state of tags:

### Step 1: Scan all pages

```
Glob: $VAULT_PATH/**/*.md (excluding _archives/, .obsidian/, _meta/)
Extract: tags field from YAML frontmatter
```

### Step 2: Build a tag frequency table

For each tag found, count how many pages use it. Flag:

- **Unknown tags** — not in the taxonomy's canonical list
- **Alias tags** — using an alias instead of the canonical form (e.g., `nextjs` instead of `react`)
- **Over-tagged pages** — pages with more than 5 tags
- **Untagged pages** — pages with no tags or empty tags field

### Step 3: Report

```markdown
## Tag Audit Report

### Summary

- Total unique tags: 47
- Canonical tags used: 32
- Non-canonical tags found: 15
- Pages over tag limit (5): 3
- Untagged pages: 2

### Non-Canonical Tags Found

| Current Tag | → Canonical | Pages Affected |
| ----------- | ----------- | -------------- |
| `nextjs`    | `react`     | 4              |
| `next-js`   | `react`     | 2              |
| `robotics`  | `ml`        | 1              |
| `windows98` | `retro`     | 3              |

### Unknown Tags (not in taxonomy)

| Tag          | Pages | Recommendation                   |
| ------------ | ----- | -------------------------------- |
| `flutter`    | 1     | Add to taxonomy under Frameworks |
| `kubernetes` | 2     | Add to taxonomy under DevOps     |

### Over-Tagged Pages

| Page                   | Tag Count | Tags                 |
| ---------------------