ci: fail validate when a plugin name is removed without a renames entry

Adds a step to the validate job that diffs plugins[].name against the
PR base and fails if any name disappeared without a corresponding key
in the top-level "renames" map. Prevents the next airwallex-style
plugin-not-found regression.

Part of CC-2871. Depends on the renames map (PR A).

Co-Authored-By: Claude <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -6,6 +6,12 @@
     "name": "Anthropic",
     "email": "support@anthropic.com"
   },
+  "renames": {
+    "adlc": "agentforce-adlc",
+    "airwallex": "airwallex-agentos",
+    "convex-backend": "convex",
+    "vals": "valtown"
+  },
   "plugins": [
     {
       "name": "42crunch-api-security-testing",

.github/workflows/validate-plugins.yml

@@ -38,6 +38,25 @@ jobs:
         with:
           fetch-depth: 0
 
+      - name: Check for renamed plugins without renames entry
+        run: |
+          set -euo pipefail
+          base="${{ github.event.pull_request.base.sha || 'origin/main' }}"
+          # Names removed from plugins[] in this diff
+          removed=$(comm -23 \
+            <(git show "$base:.claude-plugin/marketplace.json" | jq -r '.plugins[].name' | sort) \
+            <(jq -r '.plugins[].name' .claude-plugin/marketplace.json | sort))
+          [ -z "$removed" ] && { echo "No plugin names removed."; exit 0; }
+          # Renames keys present in HEAD
+          rename_keys=$(jq -r '.renames // {} | keys[]' .claude-plugin/marketplace.json | sort)
+          missing=$(comm -23 <(echo "$removed" | sort) <(echo "$rename_keys"))
+          if [ -n "$missing" ]; then
+            echo "::error::Plugin name(s) removed without a renames entry: $missing"
+            echo "Add to .claude-plugin/marketplace.json top-level \"renames\": {\"<old>\": \"<new>\"} (or null if intentionally removed)."
+            exit 1
+          fi
+          echo "All removed names have renames entries."
+
       - uses: anthropics/claude-plugins-community/.github/actions/validate-plugins@426e469f322952061102b286b378c0c9733a0934
         with:
           marketplace-path: .claude-plugin/marketplace.json

README.md

@@ -42,6 +42,21 @@ plugin-name/
 └── README.md            # Documentation
 ```
 
+## Plugin names are immutable
+
+The `name` field in a marketplace entry is an **immutable slug**. Once a plugin has been published, its `name` must not change — users have it installed under that slug, and renaming it breaks their install with a `plugin-not-found` error.
+
+- To change how a plugin is labeled in the UI, set or update `displayName` instead.
+- If a rename is genuinely unavoidable, add an entry to the top-level `renames` map in `.claude-plugin/marketplace.json` so existing installs auto-migrate:
+
+```json
+"renames": {
+  "old-name": "new-name"
+}
+```
+
+The Claude Code plugin loader reads this map and transparently rewrites the old slug to the new one on the user's next sync.
+
 ## Skill-bundle plugins
 
 When a plugin's source repository ships skills (`SKILL.md` files) without a `.claude-plugin/plugin.json` manifest, the marketplace entry can declare the skills directly using `strict: false` and an explicit `skills` array.