tool-rename-deprecation

# Tool Rename Deprecation When a tool or tool set reference name is changed, the **old name must always be added to the deprecated/legacy array** so that existing prompt files, tool configurations, and saved references continue to resolve correctly. ## When to Use Run this skill on **any change to built-in tool or tool set registration code** to catch regressions: - Renaming a tool's `toolReferenceName` - Renaming a tool set's `referenceName` - Moving a tool from one tool set to another (the old `toolSet/toolName` path becomes a legacy name) - Reviewing a PR that modifies tool registration — verify no legacy names were dropped ## Procedure ### Step 1 — Identify What Changed Determine whether you are renaming a **tool** or a **tool set**, and where it is registered: | Entity | Registration | Name field to rename | Legacy array | Stable ID (NEVER change) | |--------|-------------|---------------------|-------------|-------------------------| | Tool (`IToolData`) | TypeScript | `toolReferenceName` | `legacyToolReferenceFullNames` | `id` | | Tool (extension) | `package.json` `languageModelTools` | `toolReferenceName` | `legacyToolReferenceFullNames` | `name` (becomes `id`) | | Tool set (`IToolSet`) | TypeScript | `referenceName` | `legacyFullNames` | `id` | | Tool set (extension) | `package.json` `languageModelToolSets` | `name` or `referenceName` | `legacyFullNames` | — | **Critical:** For extension-contributed tools, the `name` field in `package.json` is mapped to `id`...