Diagram

Copy this

<div class="diagram-scroll" data-diagram>
  <pre class="mermaid diagram-source">erDiagram
  CUSTOMER ||--o{ ORDER : places
  ORDER ||--|{ LINE_ITEM : contains</pre>
</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="diagram-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

What the emitted HTML must satisfy — the table is the required surface; Python under contracts/ is the package-internal dual-lock CI runs (tests/test_contracts.py), not an app route. Standalone HTMX4: implement the API so responses match this markup. Dazzle: the agent emits SSR that already satisfies it. Do not invent attrs outside these tables. For request/response wiring see Server exchange.

contracts/diagram.py

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

Ingestion model Diagram

Server-side shape before render — one normalisation boundary for producers.

Exemplar render()

Executable in CI: the Python below is render(); the boxed preview is render(EXEMPLARS[0]) — the first fixture the dual-lock tests emit, not a separate widget and not gallery mock data.

def render(d: Diagram) -> str:
    """Model → diagram root (Mermaid shell or structural list)."""
    if d.mermaid_source:
        src = html.escape(d.mermaid_source)
        return (
            f'<div class="dz-diagram-scroll" data-dz-diagram>'
            f'<pre class="mermaid dz-diagram-source">{src}</pre>'
            f"</div>"
        )
    nodes_html = "".join(
        f'<li class="dz-diagram__node" data-dz-key="{html.escape(name, quote=True)}">'
        f"{html.escape(name)}</li>"
        for name in d.nodes
    )
    edges_html = "".join(
        f'<li class="dz-diagram__edge">'
        f'<span class="dz-diagram__edge-from">{html.escape(src)}</span>'
        f'<span class="dz-diagram__edge-arrow">→</span>'
        f'<span class="dz-diagram__edge-to">{html.escape(dst)}</span>'
        f"</li>"
        for src, dst in d.edges
    )
    return (
        f'<section class="dz-diagram" data-dz-diagram>'
        f'<ul class="dz-diagram__nodes">{nodes_html}</ul>'
        f'<ul class="dz-diagram__edges">{edges_html}</ul>'
        f"</section>"
    )

erDiagram
  CUSTOMER ||--o{ ORDER : places
  ORDER ||--|{ LINE_ITEM : contains

Notes

Source files

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

site/registry.py · contracts/diagram.py