Register State

Register State

Contract

By the end of this skill the consumer has:

• A call to usePilotState inside a `` subtree.
• A Zod schema that describes the value shape precisely enough for the LLM

to produce valid updates.

• A decision about read-only vs. writable (setter supplied or omitted).
• Understanding that the hook does not return state. It only

registers. State is owned by the consumer's useState / store.

Iron Law: the schema must match the value

usePilotState takes value: T AND schema: z.ZodType. When setValue is supplied, the schema is also handed to the auto-generated update_ action as its input schema (see packages/agentickit/src/hooks/use-pilot-state.ts lines 100-113). If the schema is looser than the TypeScript type (e.g. z.any() on a { id: string }), the AI will produce updates that pass validation but break the consumer's app at runtime. If you cannot write a precise Zod schema, this state slice is not ready to expose.

Phases

Phase 1: confirm the state shape

The hook is a registration, not a store. The consumer must already own the state:

const [total, setTotal] = useState(42);

Phase 2: write the Zod schema

Match the TypeScript type exactly. For primitives:

import { z } from "zod";
const totalSchema = z.number();

For complex objects, promote the schema to module scope and use z.infer for the corresponding TS type. This keeps the two in lockstep (see examples/todo/app/page.tsx lines 16-24).

Phase 3: call usePilotState

Read-only (AI can see total but cannot change it):

import { usePilotState } from "@hec-ovi/agentickit";

usePilotState({
  name: "cart_total",
  description: "Current cart total in USD.",
  value: total,
  schema: z.number(),
});

Writable (AI can propose whole-value updates through the registered setter):

usePilotState({
  name: "cart_total",
  description: "Current cart total in USD.",
  value: total,
  schema: z.number(),
  setValue: setTotal,
});

Passing setValue auto-registers an action named update_cart_total with mutating: true, so the user will see a confirm prompt before the write lands (see use-pilot-state.ts line 112). Do NOT also register a manual set_cart_total action; it'll duplicate.

Phase 4: name conventions

• name must be a stable identifier (snake_case recommended). It becomes

the key the LLM sees in the context block and the suffix of update_ when a setter is supplied.

• Two components registering the same name triggers a dev-mode

console.warn (see components/pilot-provider.tsx line 124-130); the later registration wins. Don't rely on this; pick unique names.

Phase 5: verify

Open the sidebar, ask "what's the current cart total?". The assistant should quote the number from the state. If it doesn't:

• Confirm the hook is inside `` (outside it, a dev warning fires

and the hook is a no-op; see use-pilot-state.ts line 62-66).

• Confirm the value changes are propagating (the hook re-pushes via

updateStateValue on every value identity change; see lines 91-94).

Anti-Patterns

• Using z.any() or z.unknown() as the schema. The LLM gets no

structural hint, and when setValue is supplied the update_ action is effectively unconstrained.

• Registering derived state. If doneCount is todos.filter(t => t.done).length,

expose todos and let the model count. Derived state goes stale.

• Passing an inline z.number() on every render. It's safe (the hook

stores the schema in a ref and reads lazily), but it's a code smell. Hoist the schema to module scope.

• Exposing secrets: auth tokens, PII, internal IDs. Whatever you register

is serialized and sent to the model provider on every turn.

Output Format

After registration, report:

• The state name and a one-line shape description.
• Whether it's read-only or writable.
• If writable: confirm the consumer knows an update_ tool now

exists and will confirm before calling their setter.

Tools Used

• Edit the component file to add the usePilotState call.
• Read packages/agentickit/src/hooks/use-pilot-state.ts to confirm the

option shape is current.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: hec-ovi
• Source: hec-ovi/agentickit
• License: MIT

Install and usage instructions live in the source repository linked above.