Form chrome — HaTchi-MaXchi

Form chrome forms Composite

The structural form pieces: titled sections, the validation-error summary, and the multi-section progress stepper.

Layer: L2 host · Recipe: unset — see docs/agent/pick-a-surface.md. Curriculum: AGENTS.md; pick matrix: docs/agent/pick-a-surface.md; blast radius: CONSUMER_MAP.md.

Validation Error

Name is required
Start date must be before end date

1Details
2Schedule
3Review

Contact details

Shown on invoices and receipts.

Full name

Copy this

html

<div class="hm-stack hm-measure">
  <div class="form-errors" role="alert">
    <svg class="form-errors-icon" xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2" aria-hidden="true"><path stroke-linecap="round" stroke-linejoin="round" d="M12 9v3.75m-9.303 3.376c-.866 1.5.217 3.374 1.948 3.374h14.71c1.73 0 2.813-1.874 1.948-3.374L13.949 3.378c-.866-1.5-3.032-1.5-3.898 0L2.697 16.126zM12 15.75h.007v.008H12v-.008z"/></svg>
    <div class="form-errors-body">
      <h3 class="form-errors-title">Validation Error</h3>
      <ul class="form-errors-list" role="list">
        <li>Name is required</li>
        <li>Start date must be before end date</li>
      </ul>
    </div>
  </div>
  <ol class="form-stepper" role="list" aria-label="Form progress">
    <li class="form-stepper-item is-not-last" aria-current="step"><span class="form-stepper-circle is-active"><span>1</span></span><span class="form-stepper-label is-active">Details</span><span class="form-stepper-connector" aria-hidden="true"></span></li>
    <li class="form-stepper-item is-not-last"><span class="form-stepper-circle"><span>2</span></span><span class="form-stepper-label">Schedule</span><span class="form-stepper-connector" aria-hidden="true"></span></li>
    <li class="form-stepper-item"><span class="form-stepper-circle"><span>3</span></span><span class="form-stepper-label">Review</span></li>
  </ol>
  <section class="form-section">
    <h3 class="form-section-title">Contact details</h3>
    <p class="form-section-note">Shown on invoices and receipts.</p>
    <div class="form-field">
      <label class="form-label" for="hm-fc-name">Full name<span class="form-required" aria-hidden="true">*</span></label>
      <input id="hm-fc-name" class="form-input" type="text" aria-required="true">
    </div>
  </section>
</div>

Server exchange

This Hyperpart has no server exchange — it is presentation or client chrome only. htmx does not issue a request on this part's behalf. If you put an affordance (hx-*) on a control that uses this markup, that action's exchange belongs to the action, not this part. See Swap contract for host-owned envelopes.

Swap contract

Agent-visible HTMX topology (ADR-0054 / decision 0012). exchange envelope = what the response may re-emit relative to the persistent slot (body_only | outer | none | host_owned | document). dual-lock validates part markup only — not this envelope. Stem: stems/morph-safe-hypermedia.md; decision: docs/decisions/0012-swap-identity-contract.md.

No host HTMX exchange on this part — presentation or client chrome only. exchange envelope: n/a.

If a host wraps this markup in hx-*, that host owns the swap contract (sole identity + envelope). Prefer innerMorph / outerMorph for stable slots; replacement for flash; body-only responses under inner swaps.

Envelope response examples

This part has no owned exchange (envelope n/a). If a host adds hx-*, that host’s envelope applies — typically body_only:

html

<!-- Host wraps this presentation part with hx-* (host owns envelope) -->
<!-- Prefer: hx-swap="innerMorph" hx-target="#panel-body" -->
<!-- Server returns body_only interior for #panel-body -->
<div class="dz-stack">content…</div>

Do not re-own the slot:

html

<!-- WRONG: server returns the presentation root with a new id every poll -->
<div id="form-chrome-root" data-dz-region>…</div>

How to use it

No extended guidance authored yet — start from Copy this and the dependency chips (Primitive = markup only; controller = load listed JS; Endpoint = implement Server exchange).

Seams

copy the partial under Copy this; keep root class and data-* modifiers so the CSS/JS bundle matches
no Server exchange on this part — pure presentation or client chrome
satisfy the DOM contract tables (CI stop-ship)

DOM contract

4 dual-lock modules for this part (contracts/form_errors.py, contracts/form_stepper.py, contracts/form_section.py, contracts/form_field.py). Read top-to-bottom: core root first, then extensions. Each Exemplar render() live box is CI fixture output for that module — not a second demo of the whole Hyperpart. What the tables require is the emitted HTML; Python under contracts/ is package-internal dual-lock (not an app route). Request/response wiring: Server exchange.

`contracts/form_errors.py`

Required in the DOM: root .form-errors (part form_errors). Emit only these attributes — inventing extras is fine only if controllers ignore them; omitting required ones fails CI (tests/test_contracts.py).

Node	Attr	Constraint
`.form-errors`	`—`	—

Module source

Import path is monorepo/package-local (from contracts._kit import …). Source-token form often uses data-*; gallery demos above are unprefixed. Do not copy this into app routes.

python

"""HYPERPART: form_errors — form-level validation error summary.

Dual-lock unit is the errors root. Title, list items, and icon are
host-owned. Class ``.dz-form-errors`` is the stable substrate root
(form-chrome CSS; no FragmentRenderer emit yet — server re-renders on
failed submit).
"""

from contracts._kit import DomContract, Node

DOM_CONTRACT = DomContract(
    part="form_errors",
    root=".dz-form-errors",
    nodes=(Node(".dz-form-errors", attrs={}),),
)

__all__ = ["DOM_CONTRACT"]

`contracts/form_stepper.py`

Required in the DOM: root .form-stepper (part form-stepper). Emit only these attributes — inventing extras is fine only if controllers ignore them; omitting required ones fails CI (tests/test_contracts.py).

Node	Attr	Constraint
`.form-stepper`	`—`	—

Module source

Import path is monorepo/package-local (from contracts._kit import …). Source-token form often uses data-*; gallery demos above are unprefixed. Do not copy this into app routes.

python

"""HYPERPART: form-stepper — multi-step form progress list.

Dual-lock unit is the stepper root. Step labels, state attrs, and wizard
controller seams are host-owned. Class ``.dz-form-stepper`` is the stable
substrate root (``_emit_form_stepper``).
"""

from contracts._kit import DomContract, Node

DOM_CONTRACT = DomContract(
    part="form-stepper",
    root=".dz-form-stepper",
    nodes=(Node(".dz-form-stepper", attrs={}),),
)

__all__ = ["DOM_CONTRACT"]

`contracts/form_section.py`

Required in the DOM: root .form-section (part form-section). Emit only these attributes — inventing extras is fine only if controllers ignore them; omitting required ones fails CI (tests/test_contracts.py).

Node	Attr	Constraint
`.form-section`	`—`	—

Module source

Import path is monorepo/package-local (from contracts._kit import …). Source-token form often uses data-*; gallery demos above are unprefixed. Do not copy this into app routes.

python

"""HYPERPART: form-section — labelled field group inside a form stack.

Dual-lock unit is the section root. Title, note, and nested fields are
host-owned. Class ``.dz-form-section`` is the stable substrate root
(``_emit_form_section``).
"""

from contracts._kit import DomContract, Node

DOM_CONTRACT = DomContract(
    part="form-section",
    root=".dz-form-section",
    nodes=(Node(".dz-form-section", attrs={}),),
)

__all__ = ["DOM_CONTRACT"]

`contracts/form_field.py`

Required in the DOM: root .form-field (part form-field). Emit only these attributes — inventing extras is fine only if controllers ignore them; omitting required ones fails CI (tests/test_contracts.py).

Node	Attr	Constraint
`.form-field`	`—`	—

Module source

Import path is monorepo/package-local (from contracts._kit import …). Source-token form often uses data-*; gallery demos above are unprefixed. Do not copy this into app routes.

python

"""HYPERPART: form-field — plain form field wrapper.

Dual-lock unit is the field root. Label, input, help, and a11y attrs are
host-owned. Class ``.dz-form-field`` is the stable substrate root
(``_emit_field``). Distinct from specialized widgets (combobox/tags/…).
"""

from contracts._kit import DomContract, Node

DOM_CONTRACT = DomContract(
    part="form-field",
    root=".dz-form-field",
    nodes=(Node(".dz-form-field", attrs={}),),
)

__all__ = ["DOM_CONTRACT"]

Notes

Sections are real <section>s with an h3 title + optional note; fields inside use the HM form primitives. The error summary is role="alert" (the server re-renders it on a failed submit). The stepper here shows RENDERED states (is-active/is-not-last, aria-current="step") — the live navigation behaviour is the wizard Hyperpart (wizard.js; the dzWizard Alpine island retired in Tier F4d). Dual-lock: form_errors + form_stepper + form_section + form_field (HMC-143).

Source files

Canonical registration in the registry. No dedicated controller — CSS for this part lives in the layered bundle.

site/registry.py · contracts/form_errors.py · contracts/form_stepper.py · contracts/form_section.py · contracts/form_field.py

Composed of

Field