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Schema Design Phase

Goal

Create schemas.tsx with all data types and Input/Output types BEFORE any pattern code.

Read First

• docs/common/concepts/types-and-schemas/default.md

• docs/common/concepts/types-and-schemas/writable.md

• docs/common/concepts/pattern.md (Input/Output section)

Rules

• ALWAYS use pattern<Input, Output>()

• Never use single-type pattern<State>() . Single-type patterns cannot be tested via .send() .

• Every editable field needs Writable<> in Input type (for write access)

• Output types never use Writable<>

• they reflect returned data shape

• Fields that could be undefined initially: use Default<T, value>

• Actions in Output type: Stream<T> (enables testing and linking)

• Sub-patterns need [NAME]: string and [UI]: VNode in Output type

Template

import { Default, NAME, Stream, UI, VNode, Writable } from "commontools";

// ============ DATA TYPES ============ export interface Item { name: Default<string, "">; done: Default<boolean, false>; }

// ============ PATTERN INPUT/OUTPUT ============ export interface ItemInput { item: Writable<Item>; // Writable in Input = pattern will modify }

export interface ItemOutput { [NAME]: string; // Required for sub-patterns [UI]: VNode; // Required for sub-patterns item: Item; // No Writable in Output toggle: Stream<void>; // Actions as Stream<T> }

Done When

• All data types defined with correct Writable/Default wrapping

• All Input/Output types defined for each sub-pattern

• No TypeScript errors: deno task ct check schemas.tsx --no-run