client-side-routing
DevelopmentHow to add routes without remounting the app shell. Use when adding a new route, fixing agent sidebar reloads on navigation, or choosing between `root.tsx` layout and pathless `_app.tsx` layout patterns.
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Client-Side Routing
Rule
All templates are single-page apps using React Router. Navigation must not remount the app shell. The agent sidebar, document tree, and any other persistent chrome must survive route changes.
Why
If the shell unmounts on every navigation, the agent chat reconnects/reloads, destroying in-progress work and hammering the backend.
Hard Rule
The app shell (AgentSidebar + any top-level navigation) must be mounted ONCE, above the <Outlet />. Never wrap each page in its own <AppLayout> / <Layout>. React sees a different component at the outlet position on each nav and unmounts the entire subtree.
Two Correct Patterns
1. All routes need the shell
Mount <AppLayout> in root.tsx around <Outlet />:
// app/root.tsx
<AppLayout>
<Outlet />
</AppLayout>
2. Mix of protected and public routes
Use a React Router pathless layout route:
app/routes/
_app.tsx # renders <AppLayout><Outlet /></AppLayout>
_app._index.tsx # / → under AppLayout
_app.settings.tsx # /settings → under AppLayout
_app.team.tsx # /team → under AppLayout
book.$slug.tsx # /book/:slug → no layout (public)
f.$.tsx # /f/* → no layout (public form filler)
The _ prefix on _app.tsx makes it a pathless parent — it contributes the layout but no URL segment. Route files prefixed with _app. nest under it and share the layout instance across navigations.
Anti-Pattern
// ❌ BAD — each route wraps its own Layout, causing full remount on every nav
export default function Settings() {
return (
<AppLayout>
<SettingsContent />
</AppLayout>
);
}
If a page needs per-route data (e.g. sidebar highlighting the active document), derive it inside the layout from useParams() / useLocation() — don't pass it as a prop through every route file.
Chat-First Routes
If / is a full-page chat such as AgentChatHome, keep the app shell mounted
around it when possible so AgentSidebar URL sync and route warmup stay active.
If the chat route intentionally lives outside the shell, add a tiny app-owned
prewarm for the routes agents commonly open from that chat. In local dev,
React Router can update the address bar before a cold Vite route chunk commits,
which makes navigation look broken even when the URL is correct.
Adding a New Route
- Pattern #1 (AppLayout in
root.tsx): just render page content — nothing else. - Pattern #2 (pathless
_app.tsx): name the file_app.<segment>.tsxfor authed routes, or bare<segment>.tsxfor public routes.
Related Skills
adding-a-feature— The four-area checklist referencing route layout patternscontext-awareness— Navigation state written on every route change