A Note Your Next.js App Can Read After a Restart

mountable.io keeps a note for your AI SDK file tools. Restart the Next.js app and read the same file from its filesystem.

Your agent writes a useful note during a request. Then the Next.js app restarts. The next request needs that note, but it is gone from memory.

mountable.io is a persistent filesystem for AI agents. Store the note there, and the next app process can read the same file. We maintain this community Next.js example independently of Vercel.

Two file tools

The example's buttons call the same AI SDK file tools an agent can call, so you can try it without a model key. Create saves the note and answers stored, and Read opens the file and returns its contents. The app chooses the note in advance, so the browser cannot pick arbitrary files.

Create leaves an existing note untouched. If a request times out, read the note before trying another write.

Restart and read

You need Node 24+, an existing paid mountable.io filesystem and an API key with access to it. The setup guide shows the private environment values to set, including the password-like token that protects the example's file actions. Normal storage and file-operation charges apply to your account.

From the cloned example directory:

npm ci
cp .env.example .env.local
# Fill in your private environment values, then start:
npm run dev

Open http://127.0.0.1:3000, enter your access token and create a short note. Select Read stored note to read it back. Stop and restart the app, then read again: the note is still in the filesystem.

Give your agent the same tools

The starter defines create_note and read_note with the AI SDK's tool function and the TypeScript mountable-sdk. Pass those definitions to your agent's generateText call when you connect your own model.

For an app with several users, give each signed-in user their own filesystem. The guide shows where to connect the tools to your backend's user lookup.

Your model provider bills separately. A filesystem cap limits storage spending, and model charges have their own bill.