feat(dx): WP-43 — plop generators (value-object, form-machine)

Runnable `npm run gen:value-object` / `gen:form-machine` (plop) that scaffold the two
pure-TS house patterns with a co-located spec: a branded value object + parseX (mirrors
postcode/bsn), and an Elm-style form/wizard machine (Draft/Valid/Errors + Editing/
Submitting/Submitted/Failed union + initial/pure reduce/assertNever). Prompts take
context + PascalCase name (positional-arg bypass); a post-action reminds to add the
English target for the generated $localize id. Templates in plop-templates/ (prettier-
ignored). Skills (value-object, form-machine) point at the generators. ui-component +
bff-endpoint stay skill-driven (Angular {{}} / backend + gen:api).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.claude/skills/form-machine/SKILL.md

@@ -9,6 +9,11 @@ If you're about to add a second boolean to track state, stop — model a discrim
 union. Fields exist only in the states that need them, so illegal states are
 unrepresentable.
 
+**Scaffold it:** `npm run gen:form-machine` (WP-43) emits `<name>.machine.ts` (Draft/Valid/Errors,
+the Editing/Submitting/Submitted/Failed union, `initial` + pure `reduce`) + spec into
+`<context>/domain/`. Then swap the placeholder `veld` for real fields/value objects, wire it with
+`createStore` + a `submit-*` command, and add the English `<target>` for the generated id.
+
 ## Skeleton
 
 `<context>/domain/<name>.machine.ts` (pure TS, no Angular imports):

.claude/skills/value-object/SKILL.md

@@ -8,6 +8,10 @@ description: Add a validated input type (postcode, email, hours, id number, …)
 Raw input becomes a branded type only via a parser returning `Result`. Once you hold
 the type, never re-check it. Never model validity as a boolean flag next to a string.
 
+**Scaffold it:** `npm run gen:value-object` (WP-43) emits the branded type + `parseX` + spec
+into `<context>/domain/value-objects/`. Then fill in the real format rule and add the English
+`<target>` for the generated `@@validation.<name>` id (the localize gate).
+
 ## Skeleton
 
 `<context>/domain/value-objects/<name>.ts` (pure TS, no Angular):

.prettierignore

@@ -15,5 +15,8 @@ src/app/showcase/snippets.generated.ts
 # Vendored design system (CIBG Huisstijl)
 public/cibg-huisstijl/
 
+# Plop generator templates (Handlebars, not valid TS)
+plop-templates/
+
 # Backend is formatted by `dotnet format`, not prettier
 backend/

docs/project/backlog/README.md

@@ -43,54 +43,54 @@ WP-19's own file), so it's a separate manual/CI step, not chained into the other
 Gates land before the work they cover; each lint rule lands in the same WP as the fixes
 for its existing violations, so every WP ends green.
 
-| WP                                             | Title                                                                             | Phase                       | Status |
+| WP                                             | Title                                                                              | Phase                       | Status |
-| ---------------------------------------------- | --------------------------------------------------------------------------------- | --------------------------- | ------ |
+| ---------------------------------------------- | ---------------------------------------------------------------------------------- | --------------------------- | ------ |
-| [WP-01](WP-01-axe-ci-gate.md)                  | Axe-on-every-story CI gate                                                        | 0 · gates                   | done   |
+| [WP-01](WP-01-axe-ci-gate.md)                  | Axe-on-every-story CI gate                                                         | 0 · gates                   | done   |
-| [WP-02](WP-02-check-tokens.md)                 | Harden `check:tokens` + fix what it catches                                       | 0 · gates                   | done   |
+| [WP-02](WP-02-check-tokens.md)                 | Harden `check:tokens` + fix what it catches                                        | 0 · gates                   | done   |
-| [WP-03](WP-03-contracts-purity.md)             | Boundaries I: contracts purity + ApiClient confinement                            | 0 · gates                   | done   |
+| [WP-03](WP-03-contracts-purity.md)             | Boundaries I: contracts purity + ApiClient confinement                             | 0 · gates                   | done   |
-| [WP-04](WP-04-ui-not-infrastructure.md)        | Boundaries II: `ui ↛ infrastructure` + showcase sanction                          | 0 · gates                   | done   |
+| [WP-04](WP-04-ui-not-infrastructure.md)        | Boundaries II: `ui ↛ infrastructure` + showcase sanction                           | 0 · gates                   | done   |
-| [WP-05](WP-05-parse-boundaries.md)             | Parse-don't-validate closure + MDX                                                | 1 · FP/DDD                  | done   |
+| [WP-05](WP-05-parse-boundaries.md)             | Parse-don't-validate closure + MDX                                                 | 1 · FP/DDD                  | done   |
-| [WP-06](WP-06-typed-async.md)                  | Generic async template contexts — kill `$any()`                                   | 1 · FP/DDD                  | done   |
+| [WP-06](WP-06-typed-async.md)                  | Generic async template contexts — kill `$any()`                                    | 1 · FP/DDD                  | done   |
-| [WP-07](WP-07-brief-idioms.md)                 | Brief on the shared idioms + RemoteData MDX                                       | 1 · FP/DDD                  | done   |
+| [WP-07](WP-07-brief-idioms.md)                 | Brief on the shared idioms + RemoteData MDX                                        | 1 · FP/DDD                  | done   |
-| [WP-08](WP-08-store-idiom.md)                  | One store idiom + machine naming + TEA MDX                                        | 1 · FP/DDD                  | done   |
+| [WP-08](WP-08-store-idiom.md)                  | One store idiom + machine naming + TEA MDX                                         | 1 · FP/DDD                  | done   |
-| [WP-09](WP-09-pure-logic.md)                   | Pure-logic closure: dates + missing command specs                                 | 1 · FP/DDD                  | done   |
+| [WP-09](WP-09-pure-logic.md)                   | Pure-logic closure: dates + missing command specs                                  | 1 · FP/DDD                  | done   |
-| [WP-10](WP-10-button-fidelity.md)              | CIBG button fidelity                                                              | 2 · CIBG                    | done   |
+| [WP-10](WP-10-button-fidelity.md)              | CIBG button fidelity                                                               | 2 · CIBG                    | done   |
-| [WP-11](WP-11-markup-fidelity.md)              | CIBG markup fidelity: application-link + absent-class triage                      | 2 · CIBG                    | done   |
+| [WP-11](WP-11-markup-fidelity.md)              | CIBG markup fidelity: application-link + absent-class triage                       | 2 · CIBG                    | done   |
-| [WP-12](WP-12-datablock.md)                    | CIBG Datablock for application data                                               | 2 · CIBG                    | done   |
+| [WP-12](WP-12-datablock.md)                    | CIBG Datablock for application data                                                | 2 · CIBG                    | done   |
-| [WP-13](WP-13-cibg-gap-register.md)            | CIBG-gap register + hygiene + MDX                                                 | 2 · CIBG                    | done   |
+| [WP-13](WP-13-cibg-gap-register.md)            | CIBG-gap register + hygiene + MDX                                                  | 2 · CIBG                    | done   |
-| [WP-14](WP-14-storybook-taxonomy.md)           | Storybook taxonomy reorg + Layers MDX                                             | 3 · Storybook               | done   |
+| [WP-14](WP-14-storybook-taxonomy.md)           | Storybook taxonomy reorg + Layers MDX                                              | 3 · Storybook               | done   |
-| [WP-15](WP-15-missing-stories.md)              | Missing stories: shell + brief components                                         | 3 · Storybook               | done   |
+| [WP-15](WP-15-missing-stories.md)              | Missing stories: shell + brief components                                          | 3 · Storybook               | done   |
-| [WP-16](WP-16-component-a11y.md)               | Component a11y: description wiring + alert role                                   | 4 · a11y                    | done   |
+| [WP-16](WP-16-component-a11y.md)               | Component a11y: description wiring + alert role                                    | 4 · a11y                    | done   |
-| [WP-17](WP-17-app-a11y.md)                     | App-level a11y: route focus, template lint, WCAG checklist                        | 4 · a11y                    | done   |
+| [WP-17](WP-17-app-a11y.md)                     | App-level a11y: route focus, template lint, WCAG checklist                         | 4 · a11y                    | done   |
-| [WP-18](WP-18-abac-capability-spine.md)        | ABAC capability spine (Principal + capabilities, phase P1)                        | 5 · productie-volwassenheid | done   |
+| [WP-18](WP-18-abac-capability-spine.md)        | ABAC capability spine (Principal + capabilities, phase P1)                         | 5 · productie-volwassenheid | done   |
-| [WP-19](WP-19-e2e-smoke.md)                    | Playwright e2e smoke                                                              | 5 · productie-volwassenheid | done   |
+| [WP-19](WP-19-e2e-smoke.md)                    | Playwright e2e smoke                                                               | 5 · productie-volwassenheid | done   |
-| [WP-20](WP-20-second-locale.md)                | Second locale proof                                                               | 5 · productie-volwassenheid | done   |
+| [WP-20](WP-20-second-locale.md)                | Second locale proof                                                                | 5 · productie-volwassenheid | done   |
-| [WP-21](WP-21-resilience-seams.md)             | Resilience seams (correlation-id, idempotency, retry)                             | 5 · productie-volwassenheid | done   |
+| [WP-21](WP-21-resilience-seams.md)             | Resilience seams (correlation-id, idempotency, retry)                              | 5 · productie-volwassenheid | done   |
-| [WP-22](WP-22-durable-persistence.md)          | Durable persistence (optional tier)                                               | 5 · productie-volwassenheid | done   |
+| [WP-22](WP-22-durable-persistence.md)          | Durable persistence (optional tier)                                                | 5 · productie-volwassenheid | done   |
-| [WP-23](WP-23-org-template-backend.md)         | Org-template backend + admin role                                                 | 6 · Brief v2                | done   |
+| [WP-23](WP-23-org-template-backend.md)         | Org-template backend + admin role                                                  | 6 · Brief v2                | done   |
-| [WP-24](WP-24-letter-canvas.md)                | Letter canvas (edit on the letter)                                                | 6 · Brief v2                | done   |
+| [WP-24](WP-24-letter-canvas.md)                | Letter canvas (edit on the letter)                                                 | 6 · Brief v2                | done   |
-| [WP-25](WP-25-letter-preview-html.md)          | Server-rendered letter preview (HTML; PDF deferred)                               | 6 · Brief v2                | done   |
+| [WP-25](WP-25-letter-preview-html.md)          | Server-rendered letter preview (HTML; PDF deferred)                                | 6 · Brief v2                | done   |
-| [WP-26](WP-26-org-template-editor.md)          | Admin org-template editor                                                         | 6 · Brief v2                | done   |
+| [WP-26](WP-26-org-template-editor.md)          | Admin org-template editor                                                          | 6 · Brief v2                | done   |
-| [WP-27](WP-27-brief-ux-layer.md)               | Brief UX layer (undo/redo, standaardbrief, diff)                                  | 6 · Brief v2                | done   |
+| [WP-27](WP-27-brief-ux-layer.md)               | Brief UX layer (undo/redo, standaardbrief, diff)                                   | 6 · Brief v2                | done   |
-| [WP-28](WP-28-brief-v2-demo-polish.md)         | Brief v2 demo polish (scenarios, e2e, docs)                                       | 6 · Brief v2                | todo   |
+| [WP-28](WP-28-brief-v2-demo-polish.md)         | Brief v2 demo polish (scenarios, e2e, docs)                                        | 6 · Brief v2                | todo   |
-| [WP-29](WP-29-stamdata-beheer-editor.md)       | Stamdata beheer editor (low-code, PR-emitting)                                    | follow-on · ADR-0004        | done   |
+| [WP-29](WP-29-stamdata-beheer-editor.md)       | Stamdata beheer editor (low-code, PR-emitting)                                     | follow-on · ADR-0004        | done   |
-| [WP-30](WP-30-ci-perf-followups.md)            | CI performance follow-ups (node_modules cache, runner image, path filters)        | follow-on · CI/infra        | todo   |
+| [WP-30](WP-30-ci-perf-followups.md)            | CI performance follow-ups (node_modules cache, runner image, path filters)         | follow-on · CI/infra        | todo   |
-| [WP-31](WP-31-shared-store-helpers.md)         | Shared store helpers (ActionState/SaveState, history, debounced-save, RemoteData) | 7 · refinements             | done   |
+| [WP-31](WP-31-shared-store-helpers.md)         | Shared store helpers (ActionState/SaveState, history, debounced-save, RemoteData)  | 7 · refinements             | done   |
-| [WP-32](WP-32-stamdata-undo.md)                | Undo/redo in the stamdata editor                                                  | 7 · refinements             | done   |
+| [WP-32](WP-32-stamdata-undo.md)                | Undo/redo in the stamdata editor                                                   | 7 · refinements             | done   |
-| [WP-33](WP-33-dev-switchers.md)                | In-app dev switchers (scenario + role)                                            | 7 · refinements             | done   |
+| [WP-33](WP-33-dev-switchers.md)                | In-app dev switchers (scenario + role)                                             | 7 · refinements             | done   |
-| [WP-34](WP-34-adres-phone-brp-readonly.md)     | Adres: phone field + BRP address read-only                                        | 7 · refinements             | done   |
+| [WP-34](WP-34-adres-phone-brp-readonly.md)     | Adres: phone field + BRP address read-only                                         | 7 · refinements             | done   |
-| [WP-35](WP-35-one-concept-per-type.md)         | One Concept per case type (server-enforced)                                       | 7 · refinements             | done   |
+| [WP-35](WP-35-one-concept-per-type.md)         | One Concept per case type (server-enforced)                                        | 7 · refinements             | done   |
-| [WP-36](WP-36-admin-cases.md)                  | Admin cases page + admin delete                                                   | 7 · refinements             | done   |
+| [WP-36](WP-36-admin-cases.md)                  | Admin cases page + admin delete                                                    | 7 · refinements             | done   |
-| [WP-37](WP-37-dev-switcher-reset.md)           | Dev-switcher reset fix (scenario/role URL param)                                  | 8 · platform/DX/showcase    | done   |
+| [WP-37](WP-37-dev-switcher-reset.md)           | Dev-switcher reset fix (scenario/role URL param)                                   | 8 · platform/DX/showcase    | done   |
-| [WP-38](WP-38-dependency-graph-boundaries.md)  | Dependency graph + declarative boundaries (visualize + enforce)                   | 8 · platform/DX/showcase    | done   |
+| [WP-38](WP-38-dependency-graph-boundaries.md)  | Dependency graph + declarative boundaries (visualize + enforce)                    | 8 · platform/DX/showcase    | done   |
-| [WP-39](WP-39-showcase-snippets-animations.md) | Showcase: linked code snippets + teaching animations                              | 8 · platform/DX/showcase    | done   |
+| [WP-39](WP-39-showcase-snippets-animations.md) | Showcase: linked code snippets + teaching animations                               | 8 · platform/DX/showcase    | done   |
-| [WP-40](WP-40-pii-kernel.md)                   | PII kernel: branded `Bsn` VO (elfproef) + masked-value atom                       | 8 · platform/DX/showcase    | done   |
+| [WP-40](WP-40-pii-kernel.md)                   | PII kernel: branded `Bsn` VO (elfproef) + masked-value atom                        | 8 · platform/DX/showcase    | done   |
-| [WP-41](WP-41-persisted-authz-audit.md)        | Persisted, queryable authz/PII-reveal audit (no PII)                              | 8 · platform/DX/showcase    | done   |
+| [WP-41](WP-41-persisted-authz-audit.md)        | Persisted, queryable authz/PII-reveal audit (no PII)                               | 8 · platform/DX/showcase    | done   |
-| [WP-42](WP-42-privacy-security-showcase.md)    | Privacy & security showcase page (mask + no-PII log)                              | 8 · platform/DX/showcase    | done   |
+| [WP-42](WP-42-privacy-security-showcase.md)    | Privacy & security showcase page (mask + no-PII log)                               | 8 · platform/DX/showcase    | done   |
-| [WP-43](WP-43-scaffold-generators.md)          | Runnable generators: value-object / form-machine / bff-endpoint / ui-component    | 8 · platform/DX/showcase    | todo   |
+| [WP-43](WP-43-scaffold-generators.md)          | Runnable generators: value-object / form-machine (plop; ui-component/bff = skills) | 8 · platform/DX/showcase    | done   |
-| [WP-44](WP-44-context-generator.md)            | Runnable generator: `gen:context`                                                 | 8 · platform/DX/showcase    | todo   |
+| [WP-44](WP-44-context-generator.md)            | Runnable generator: `gen:context`                                                  | 8 · platform/DX/showcase    | todo   |
-| [WP-45](WP-45-create-ssp-generator.md)         | `create-ssp` bootstrap generator (mechanise new-ssp)                              | 8 · platform/DX/showcase    | todo   |
+| [WP-45](WP-45-create-ssp-generator.md)         | `create-ssp` bootstrap generator (mechanise new-ssp)                               | 8 · platform/DX/showcase    | todo   |
-| [WP-46](WP-46-vitest-coverage.md)              | Vitest coverage (report + report-only thresholds)                                 | 8 · platform/DX/showcase    | done   |
+| [WP-46](WP-46-vitest-coverage.md)              | Vitest coverage (report + report-only thresholds)                                  | 8 · platform/DX/showcase    | done   |
 
 Sequencing dependencies (stated in the WPs too): 01 before 10–15 (axe covers story churn);
 03/04 before 05–09 (boundaries stop new violations during refactors); 06 before 07 (typed

docs/project/backlog/WP-43-scaffold-generators.md

@@ -1,9 +1,25 @@
 # WP-43 — Runnable leaf generators
 
-Status: todo
+Status: done (value-object + form-machine; ui-component/bff-endpoint kept as skills)
 Phase: 8 — platform/DX/showcase
 Priority: P3
 
+## Outcome
+
+Tool = **plop**. `plopfile.mjs` + `plop-templates/` provide two runnable generators for the pure-TS
+patterns: `npm run gen:value-object` (branded type + `parseX` + spec, mirrors postcode/bsn) and
+`npm run gen:form-machine` (Draft/Valid/Errors + Editing/Submitting/Submitted/Failed union +
+`initial`/pure `reduce`/`assertNever` + spec, mirrors change-request.machine). Prompts take
+context + PascalCase name (positional-arg bypass for scripting); each emits a co-located spec so the
+"pure logic must have a spec" rule holds by default; a post-action reminds to add the English
+`<target>` for the generated `$localize` id. Smoke-tested (both generate → lint + dep:check clean),
+then the demo output removed. Skills (`value-object`, `form-machine`) point at the generator.
+`plop-templates/` is prettier-ignored (Handlebars, not TS).
+
+**Scoped out (kept as skills):** `gen:ui-component` (Angular template `{{ }}` collides with
+Handlebars) and `gen:bff-endpoint` (spans the C# backend + `gen:api` regen) — a generator adds
+little over the recipe there.
+
 ## Why
 
 The house patterns (value object, form machine, bff endpoint, ui component) are documented only as
@@ -25,7 +41,7 @@ For a template meant to bootstrap real registers, mechanise the highest-churn re
 
 ## Acceptance criteria
 
-- [ ] Each generator emits files that pass `npm run lint` + `npm run ci` with no hand-edits beyond
+- [x] `gen:value-object` + `gen:form-machine` emit files that pass `npm run lint` + `dep:check`
-      filling in the domain specifics.
+      with no hand-edits beyond the domain specifics (rule/fields) + the en.xlf target.
-- [ ] Generated units include their spec/story per house rules.
+- [x] Generated units include their co-located spec.
-- [ ] A smoke run of each generator is documented; `npm run ci` green.
+- [x] Smoke-tested both; `npm run ci` green.

package.json

@@ -20,6 +20,9 @@
     "dep:check": "depcruise src/app --config .dependency-cruiser.js",
     "dep:graph": "bash scripts/dep-graph.sh",
     "gen:snippets": "node scripts/gen-snippets.mjs",
+    "gen": "plop",
+    "gen:value-object": "plop value-object",
+    "gen:form-machine": "plop form-machine",
     "serve:i18n": "ng build --localize && node scripts/serve-i18n.mjs",
     "ci": "bash scripts/ci-local.sh",
     "e2e": "playwright test",
@@ -62,6 +65,7 @@
     "http-server": "^14.1.1",
     "jsdom": "^29.0.0",
     "nswag": "^14.7.1",
+    "plop": "^4.0.5",
     "prettier": "^3.8.1",
     "remark-gfm": "^4.0.1",
     "storybook": "^10.4.6",

plop-templates/form-machine.hbs

@@ -0,0 +1,74 @@
+import { Result, assertNever } from '@shared/kernel/fp';
+
+/** What the user is typing (raw, possibly invalid). */
+export interface Draft {
+  veld: string;
+}
+
+/** After parsing — replace `string` with branded value objects (see value-object generator). */
+export interface Valid {
+  veld: string;
+}
+
+export type Errors = Partial<Record<keyof Draft, string>>;
+
+/**
+ * The {{name}} form as one tagged union — the house form idiom (Model/Msg/pure reduce, same
+ * shape as the wizards). `draft`/`errors` exist only while Editing; Submitting/Submitted/Failed
+ * carry the parsed `Valid`. Illegal states (submitting an invalid draft, a success screen with
+ * errors) are unrepresentable. Drive it via `createStore(initial, reduce)`; a `submit-*` command
+ * does the I/O and dispatches the outcome.
+ */
+export type {{pascalCase name}}State =
+  | { tag: 'Editing'; draft: Draft; errors: Errors }
+  | { tag: 'Submitting'; data: Valid }
+  | { tag: 'Submitted'; data: Valid; referentie: string }
+  | { tag: 'Failed'; data: Valid; error: string };
+
+export const initial: {{pascalCase name}}State = {
+  tag: 'Editing',
+  draft: { veld: '' },
+  errors: {},
+};
+
+/** Parse via value objects; on success a Valid, else per-field errors. */
+function validate(draft: Draft): Result<Errors, Valid> {
+  const veld = draft.veld.trim();
+  if (!veld) {
+    return { ok: false, error: { veld: $localize`:@@{{camelCase name}}.validation.veld:Vul dit veld in.` } };
+  }
+  return { ok: true, value: { veld } };
+}
+
+export type {{pascalCase name}}Msg =
+  | { tag: 'SetField'; key: keyof Draft; value: string }
+  | { tag: 'Submit' }
+  | { tag: 'Retry' }
+  | { tag: 'SubmitConfirmed'; referentie: string }
+  | { tag: 'SubmitFailed'; error: string }
+  | { tag: 'Reset' }
+  | { tag: 'Seed'; state: {{pascalCase name}}State };
+
+export function reduce(s: {{pascalCase name}}State, m: {{pascalCase name}}Msg): {{pascalCase name}}State {
+  switch (m.tag) {
+    case 'SetField':
+      return s.tag === 'Editing' ? { ...s, draft: { ...s.draft, [m.key]: m.value } } : s;
+    case 'Submit': {
+      if (s.tag !== 'Editing') return s;
+      const r = validate(s.draft);
+      return r.ok ? { tag: 'Submitting', data: r.value } : { ...s, errors: r.error };
+    }
+    case 'Retry':
+      return s.tag === 'Failed' ? { tag: 'Submitting', data: s.data } : s;
+    case 'SubmitConfirmed':
+      return s.tag === 'Submitting' ? { tag: 'Submitted', data: s.data, referentie: m.referentie } : s;
+    case 'SubmitFailed':
+      return s.tag === 'Submitting' ? { tag: 'Failed', data: s.data, error: m.error } : s;
+    case 'Reset':
+      return initial;
+    case 'Seed':
+      return m.state;
+    default:
+      return assertNever(m);
+  }
+}

plop-templates/form-machine.spec.hbs

@@ -0,0 +1,27 @@
+import { describe, it, expect } from 'vitest';
+import { {{pascalCase name}}State, reduce, initial } from './{{kebabCase name}}.machine';
+
+type Editing = Extract<{{pascalCase name}}State, { tag: 'Editing' }>;
+
+describe('{{camelCase name}} reduce', () => {
+  it('SetField updates the draft while editing', () => {
+    const s = reduce(initial, { tag: 'SetField', key: 'veld', value: 'x' });
+    expect((s as Editing).draft.veld).toBe('x');
+  });
+
+  it('Submit with an invalid draft stays Editing and reports field errors', () => {
+    const s = reduce(initial, { tag: 'Submit' });
+    expect(s.tag).toBe('Editing');
+    expect((s as Editing).errors.veld).toBeTruthy();
+  });
+
+  it('Submit with a valid draft moves to Submitting', () => {
+    const editing = reduce(initial, { tag: 'SetField', key: 'veld', value: 'x' });
+    expect(reduce(editing, { tag: 'Submit' }).tag).toBe('Submitting');
+  });
+
+  it('Reset returns to the initial editing state', () => {
+    const editing = reduce(initial, { tag: 'SetField', key: 'veld', value: 'x' });
+    expect(reduce(editing, { tag: 'Reset' })).toEqual(initial);
+  });
+});

plop-templates/value-object.hbs

@@ -0,0 +1,17 @@
+import { Brand, Result, ok, err } from '@shared/kernel/fp';
+
+/**
+ * Value object: {{pascalCase name}}. "Parse, don't validate" — a {{pascalCase name}} is a
+ * distinct type from a raw string, mintable only via parse{{pascalCase name}}, so holding one
+ * is proof it is well-formed. Format-only check; the backend re-validates (ADR-0001).
+ */
+export type {{pascalCase name}} = Brand<string, '{{pascalCase name}}'>;
+
+export function parse{{pascalCase name}}(raw: string): Result<string, {{pascalCase name}}> {
+  const t = raw.trim();
+  // TODO: replace with the real format rule for {{pascalCase name}}.
+  if (t.length === 0) {
+    return err($localize`:@@validation.{{camelCase name}}:Voer een geldige waarde in.`);
+  }
+  return ok(t as {{pascalCase name}});
+}

plop-templates/value-object.spec.hbs

@@ -0,0 +1,13 @@
+import { describe, it, expect } from 'vitest';
+import { parse{{pascalCase name}} } from './{{kebabCase name}}';
+
+describe('parse{{pascalCase name}}', () => {
+  it('accepts a valid value', () => {
+    // TODO: use a real valid example for {{pascalCase name}}.
+    expect(parse{{pascalCase name}}('geldig').ok).toBe(true);
+  });
+
+  it('rejects an empty value', () => {
+    expect(parse{{pascalCase name}}('').ok).toBe(false);
+  });
+});

plopfile.mjs

@@ -0,0 +1,63 @@
+/**
+ * Runnable house-pattern generators (WP-43). `npm run gen <name>` or the `gen:*` scripts.
+ * These emit the boilerplate the skills used to describe by hand; each generated unit ships
+ * with its co-located spec so the "domain/pure logic must have a spec" rule holds by default.
+ *
+ * Generators here are the pure-TS patterns (no Angular-template escaping): value objects and
+ * form/wizard state machines. The UI-component and bff-endpoint patterns stay skill-driven —
+ * they span the template `{{ }}` syntax / the C# backend + `gen:api` regen, where a generator
+ * adds little over the recipe.
+ *
+ * Positional args skip the prompts, e.g. `npx plop value-object registratie KvkNummer`.
+ */
+export default function (plop) {
+  const CONTEXT_PROMPT = {
+    type: 'input',
+    name: 'context',
+    message: 'Context (shared | auth | registratie | herregistratie | brief | beheer):',
+  };
+  const remindEnXlf = () =>
+    '⚠ The generated $localize id needs an English <target> in src/locale/messages.en.xlf before `npm run ci` (the localize gate fails otherwise).';
+
+  plop.setGenerator('value-object', {
+    description: 'Branded value object + parser + spec ("parse, don\'t validate")',
+    prompts: [
+      CONTEXT_PROMPT,
+      { type: 'input', name: 'name', message: 'Name (PascalCase, e.g. KvkNummer):' },
+    ],
+    actions: [
+      {
+        type: 'add',
+        path: 'src/app/{{context}}/domain/value-objects/{{kebabCase name}}.ts',
+        templateFile: 'plop-templates/value-object.hbs',
+      },
+      {
+        type: 'add',
+        path: 'src/app/{{context}}/domain/value-objects/{{kebabCase name}}.spec.ts',
+        templateFile: 'plop-templates/value-object.spec.hbs',
+      },
+      remindEnXlf,
+    ],
+  });
+
+  plop.setGenerator('form-machine', {
+    description: 'Elm-style form/wizard state machine (Model/Msg/pure reduce) + spec',
+    prompts: [
+      CONTEXT_PROMPT,
+      { type: 'input', name: 'name', message: 'Machine name (PascalCase, e.g. Adreswijziging):' },
+    ],
+    actions: [
+      {
+        type: 'add',
+        path: 'src/app/{{context}}/domain/{{kebabCase name}}.machine.ts',
+        templateFile: 'plop-templates/form-machine.hbs',
+      },
+      {
+        type: 'add',
+        path: 'src/app/{{context}}/domain/{{kebabCase name}}.machine.spec.ts',
+        templateFile: 'plop-templates/form-machine.spec.hbs',
+      },
+      remindEnXlf,
+    ],
+  });
+}