feat: add an Nx generator for React playground apps

.agents/skills/new-react-playground/SKILL.md

@@ -0,0 +1,32 @@
+---
+name: new-react-playground
+description: Use when an agent in this TanStack AI monorepo needs a playground app to try a new feature. Trigger: new feature to try in a Start React app in this repo.
+---
+
+# new-react-playground
+
+Pick a kebab-case name. Then generate a React chat lab under `examples/<name>/`.
+
+The generator writes a thin chat lab. The app includes:
+
+- BYOK
+- Model picker
+- `/api/chat` with `chat()`
+
+The index route is the chat shell. The dev server uses port `3100`.
+
+## Must
+
+1. Pick a kebab-case name.
+2. From the repo root, run `pnpm nx g @tanstack/workspace-plugin:react-app <name>`.
+3. Run `pnpm install`.
+4. Implement the feature on the index route. If the server must change, edit `/api/chat`.
+5. Run `pnpm --filter <name> dev` (port 3100).
+
+Do not commit the new example. After a human asks to keep it, you can commit it.
+
+## Later
+
+If you need live model keys, copy `.env.example` to `.env.local`.
+
+Open `http://localhost:3100`. The chat lab is live. Your feature is on the index route.

.changeset/config.json

@@ -11,6 +11,7 @@
   "fixed": [],
   "linked": [],
   "ignore": [
+    "@tanstack/workspace-plugin",
     "@tanstack/ai-codemods",
     "@tanstack/ai-code-mode-models-eval",
     "@tanstack/ai-e2e",

.claude/skills/new-react-playground/SKILL.md

@@ -0,0 +1,32 @@
+---
+name: new-react-playground
+description: Use when an agent in this TanStack AI monorepo needs a playground app to try a new feature. Trigger: new feature to try in a Start React app in this repo.
+---
+
+# new-react-playground
+
+Pick a kebab-case name. Then generate a React chat lab under `examples/<name>/`.
+
+The generator writes a thin chat lab. The app includes:
+
+- BYOK
+- Model picker
+- `/api/chat` with `chat()`
+
+The index route is the chat shell. The dev server uses port `3100`.
+
+## Must
+
+1. Pick a kebab-case name.
+2. From the repo root, run `pnpm nx g @tanstack/workspace-plugin:react-app <name>`.
+3. Run `pnpm install`.
+4. Implement the feature on the index route. If the server must change, edit `/api/chat`.
+5. Run `pnpm --filter <name> dev` (port 3100).
+
+Do not commit the new example. After a human asks to keep it, you can commit it.
+
+## Later
+
+If you need live model keys, copy `.env.example` to `.env.local`.
+
+Open `http://localhost:3100`. The chat lab is live. Your feature is on the index route.

.grok/skills/new-react-playground/SKILL.md

@@ -0,0 +1,32 @@
+---
+name: new-react-playground
+description: Use when an agent in this TanStack AI monorepo needs a playground app to try a new feature. Trigger: new feature to try in a Start React app in this repo.
+---
+
+# new-react-playground
+
+Pick a kebab-case name. Then generate a React chat lab under `examples/<name>/`.
+
+The generator writes a thin chat lab. The app includes:
+
+- BYOK
+- Model picker
+- `/api/chat` with `chat()`
+
+The index route is the chat shell. The dev server uses port `3100`.
+
+## Must
+
+1. Pick a kebab-case name.
+2. From the repo root, run `pnpm nx g @tanstack/workspace-plugin:react-app <name>`.
+3. Run `pnpm install`.
+4. Implement the feature on the index route. If the server must change, edit `/api/chat`.
+5. Run `pnpm --filter <name> dev` (port 3100).
+
+Do not commit the new example. After a human asks to keep it, you can commit it.
+
+## Later
+
+If you need live model keys, copy `.env.example` to `.env.local`.
+
+Open `http://localhost:3100`. The chat lab is live. Your feature is on the index route.

CONTRIBUTING.md

@@ -92,6 +92,18 @@ All commands are run from the repo root. Nx handles affected detection and cachi
 
 Working on a single package? `cd packages/<pkg>` and use its scripts directly (`pnpm test:lib`, `pnpm test:types`, etc.).
 
+## Generate a React playground
+
+You need a TanStack Start chat app to try a feature. Do not copy `examples/ts-react-chat`. Run the generator.
+
+1. From the repo root, run `pnpm nx g @tanstack/workspace-plugin:react-app <name>`.
+2. Run `pnpm install`.
+3. Copy `examples/<name>/.env.example` to `examples/<name>/.env.local` and add a key.
+4. Run `pnpm --filter <name> dev` (port 3100).
+5. Change the index route for the feature. If the server must change, change `/api/chat`.
+
+Do not commit the new example unless you mean to keep it as a lasting example.
+
 ## TypeScript configuration
 
 There is a single `tsconfig.base.json` at the repo root with the shared `compilerOptions`. Every package extends it and overrides only what's unique to that package (e.g. `outDir`, JSX runtime, framework lib).

knip.json

@@ -9,6 +9,7 @@
   "ignoreWorkspaces": [
     "examples/**",
     "testing/**",
+    "tools/**",
     "packages/ai-code-mode/models-eval"
   ],
   "ignore": [

nx.json

@@ -4,6 +4,7 @@
   "nxCloudId": "6928ccd60a2e27ab22f38ad0",
   "useDaemonProcess": true,
   "useInferencePlugins": false,
+  "plugins": ["@tanstack/workspace-plugin"],
   "analytics": false,
   "parallel": 15,
   "tui": {