Server primitives

Server primitives for Vite apps and any host

ViteHub adds storage, queues, schedules, email, and other server APIs to Vite apps. Call them from routes, handlers, jobs, or workers. You don't need an Agent Definition.

Start with Your first server primitive for a runnable example. Return to Concepts when you need to understand generated imports or host configuration. Read the Agents section only when a model needs access to one of these APIs.

Pick the right primitive

Use primitives from server code

Most primitives expose the same application import on every host. ViteHub connects that import to the selected provider during the build.

import { kv } from 'vite-hub/kv'

export default defineEventHandler(async (event) => {
  const [error] = await kv.set('settings', await readBody(event))
  if (error) throw error
  return { ok: true }
})

The route doesn't need to know whether KV uses local files, Cloudflare, Vercel, or another driver.

Definitions and generated output

Some primitives work directly after configuration. Env, KV, Blob, Source, and Shell can often be called from server code without a discovered Definition.

Other primitives need a Definition so ViteHub can discover runtime behavior or named work. Email composes one declaratively configured provider, while Auth uses a singleton Definition bound at runtime. Database schemas, Workspace Definitions, Queue Definitions, Workflow Definitions, Static Schedule Definitions, Sandbox Definitions, and Agent Definitions can also generate Runtime Registries or host-specific Provider Output. Rate Limit uses source-local handles with explicit stable IDs instead of location-derived Definitions.

Connect primitives to Agents

Capabilities expose controlled agent-facing access to primitives. A storage Capability can expose scoped read/edit tools, a Schedule Capability can manage allowed Runtime Schedules, and workspaceShell() can expose file inspection through Workspace and Shell boundaries.

Don't expose a server API to a model just because the app uses it. Add the relevant Official Capability only when the Agent needs that ability. Configure its scope, write mode, and approvals for that task.

Next steps

• Build the first primitive
• Build the first Agent
• Read the shared primitive pattern