Typed State

A state.ts file gives a route typed state. Here's a /hello/[tenant] workflow whose state includes its tenant:

import { z } from "zod"
 
export default z.object({
  /** Tenant supplied in the run input */
  tenant: z.string(),
  /** Accumulated tool-call results */
  context: z.string().default(""),
  /** Number of records returned by the lookup tool */
  count: z.number().default(0),
})

NotesCopy link to section: Notes

Include route values in the schema. [tenant] is part of the route id. The workflow validates tenant from the input by calling state.parse(input).
Route ids stay parameterized. Run this route as /hello/[tenant] with input for tenant:
bash
```
echo '{"tenant":"acme"}' | b4 run '/hello/[tenant]'
```
For an Agent Protocol run, send the same input in the body:
json
```
{ "route": "/hello/[tenant]#workflow", "input": { "tenant": "acme" } }
```
B4.run fills route state from the input, never from a concrete path like /hello/acme.
Parse workflow input yourself. A workflow route receives its input as is. Calling state.parse(input) validates it and fills in fields declared with .default(...) when the caller leaves them out.
This workflow imports and parses the schema directly, so it can keep tenant required. For agent-state discovery, B4.run validates {} to extract defaults. If you reuse this schema for an agent route, make every top-level field accept missing input, or discovery skips the schema.
State is JSON-serializable. It's serialized on every runs/wait and runs/stream call, so use primitives, plain objects, and arrays.