Message scroller

Copy this

<div class="message-scroller" data-message-scroller role="log" aria-label="Conversation" aria-live="polite" tabindex="0">
  <div class="message" data-message data-from="in">
    <span class="message__media" aria-hidden="true">MR</span>
    <div class="message__body">
      <div class="message__meta"><span class="message__author">Maya Reyes</span><time class="message__time" datetime="2026-07-12T10:02">10:02</time></div>
      <div class="bubble" data-bubble data-from="in">
        <p>Can we reschedule the walkthrough to Thursday?</p>
      </div>
    </div>
  </div>
  <div class="message" data-message data-from="out">
    <span class="message__media" aria-hidden="true">You</span>
    <div class="message__body">
      <div class="message__meta"><span class="message__author">You</span><time class="message__time" datetime="2026-07-12T10:04">10:04</time></div>
      <div class="bubble" data-bubble data-from="out">
        <p>Thursday 14:00 works — I'll send a calendar hold.</p>
      </div>
    </div>
  </div>
  <div class="message" data-message data-from="in">
    <span class="message__media" aria-hidden="true">MR</span>
    <div class="message__body">
      <div class="message__meta"><span class="message__author">Maya Reyes</span><time class="message__time" datetime="2026-07-12T10:05">10:05</time></div>
      <div class="bubble" data-bubble data-from="in">
        <p>Perfect — see you then.</p>
      </div>
    </div>
  </div>
</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:

<!-- 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:

<!-- WRONG: server returns the presentation root with a new id every poll -->
<div id="message-scroller-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

3 dual-lock modules for this part (contracts/message_scroller.py, contracts/message.py, contracts/bubble.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/message_scroller.py

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

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.

"""HYPERPART: message_scroller — chat transcript viewport (scrollable message stack).

Dual-lock unit is the scroller root. Message children, live-region attrs, and
scroll behaviour are host-owned. Class ``.dz-message-scroller`` is the stable
substrate root (FragmentRenderer: ``MessageScroller`` under ``display: conversation``).
"""

from contracts._kit import DomContract, Node

DOM_CONTRACT = DomContract(
    part="message_scroller",
    root=".dz-message-scroller",
    nodes=(Node(".dz-message-scroller", attrs={}),),
)

__all__ = ["DOM_CONTRACT"]

contracts/message.py

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

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.

"""HYPERPART: message — chat message row (media + meta + bubble).

Dual-lock unit is the message root. Author/time, bubble body, and
``data-dz-from`` orientation are host-owned. Class ``.dz-message`` is the
stable substrate root (gallery CSS; Fragment ``Message`` +
``display: conversation`` emit the spine with nested ``Bubble``).
"""

from contracts._kit import DomContract, Node

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

__all__ = ["DOM_CONTRACT"]

contracts/bubble.py

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

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.

"""HYPERPART: bubble — chat bubble content shell (inbound/outbound).

Dual-lock unit is the bubble root. Body copy and ``data-dz-from`` orientation
are host-owned. Class ``.dz-bubble`` is the stable substrate root (gallery CSS;
Fragment ``Bubble`` nests inside ``Message`` under ``display: conversation``).
Compose inside message rows for full chat UI.
"""

from contracts._kit import DomContract, Node

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

__all__ = ["DOM_CONTRACT"]

Notes

Source files

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

site/registry.py · contracts/message_scroller.py · contracts/message.py · contracts/bubble.py