# Dialog (`dialog`)

Modal on the native <dialog> — one line of JS to open, close for free (Esc / backdrop / method=dialog submit). Focus-trapped by the platform.

> **Layer:** L1 surface · **Recipe:** `overlay-dialog` — modal / drawer overlay
> Curriculum: `AGENTS.md` · pick matrix: `docs/agent/pick-a-surface.md` · blast radius: `CONSUMER_MAP.md`

> **Dialect:** Partial below is **unprefixed** (gallery / standalone HM). DOM contract Python often uses the **source token** `data-dz-*` / `dz-*` (Dazzle dual-lock). Match the CSS/JS bundle you load.

> **Demo vs contract:** Live gallery behaviour may use `/mock/*` or flash toasts. Those are **offline demos only** — implement **Server exchange** + **DOM contract**, not the mock. See AGENTS.md › Gallery demos.

## Copy this

```html
<!-- icons: include the icon sheet once per page (see the Setup section, #setup) -->
<button class="button" data-variant="primary" data-dialog-open="hm-dialog-demo">Delete workspace…</button>
<dialog class="dialog" id="hm-dialog-demo" aria-labelledby="hm-dialog-demo-title" closedby="any">
  <form method="dialog">
    <div class="dialog__header">
      <h2 class="dialog__title" id="hm-dialog-demo-title">Delete workspace?</h2>
      <button type="submit" class="dialog__close" aria-label="Close dialog"><svg class="icon" aria-hidden="true"><use href="#i-x"/></svg></button>
    </div>
    <div class="dialog__body">
      <p>This permanently deletes the workspace and every record in it. This action cannot be undone.</p>
    </div>
    <div class="dialog__footer"><button type="submit" class="button" data-variant="outline">Cancel</button><button type="submit" class="button" data-variant="destructive" value="confirm">Delete</button></div>
  </form>
</dialog>
```

## Server exchange

This Hyperpart has **no server exchange** — presentation or client chrome only. If you put `hx-*` on a control that uses this markup, that action's exchange belongs to the action, not this part.

## 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`.

**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

What the **server returns** for each exchange. Match the **exchange envelope**; dual-lock still applies to interior markup.

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

```html
<!-- Prefer hx-swap=innerMorph into a stable body slot -->
<div class="dz-stack">content…</div>
```

Do **not** re-own the slot:

```html
<div id="dialog-root" data-dz-region>…</div>
```

## How to use it

### Seams

- addressing: data-dz-dialog-open → showModal on dialog#id (N instances)
- author full dialog HTML (header/body/footer) — chrome you own
- confirm button may carry hx-delete / form submit; closing is native
- pick-a-surface: custom modal body → dialog; yes/no on hx-* → confirm

### Do / Don't

| Do | Don't |
|---|---|
| use native <dialog> with data-dz-dialog-open triggers | build a div[role=dialog] + manual focus trap |
| author one dialog per designed flow (addressing) | duplicate a full dialog for every Delete when hx-confirm suffices |

### Pitfalls

- do not re-implement close with custom overlays — use <dialog> + showModal
- returnValue on the confirm button is the hand-off for form-less actions
- do not use dialog for fleet hx-confirm upgrades — that is confirm (gating)

### Keyboard / AT

- Esc dismisses natively; focus is restored to the open trigger
- confirm / cancel are real buttons inside the dialog

### Related parts

- `button` — agents/button.md

## DOM contract

What emitted markup must satisfy (CI: `tests/test_contracts.py`). Do not invent attrs outside the tables. Python modules under `contracts/` are **package-internal dual-locks** (`from contracts._kit import …`) — not FastAPI business handlers. App servers implement **Server exchange** endpoints; this section constrains the HTML those endpoints return.

### `contracts/dialog.py`

- **Required root:** `[data-dz-dialog-open]` (part `dialog`)

| Node | Attr | Constraint |
|---|---|---|
| `[data-dz-dialog-open]` | `data-dz-dialog-open` | present (any value) |

#### Module source

Monorepo dual-lock only — import `contracts._kit` from the HM package. Do not paste into app route modules.

```python
"""HYPERPART: dialog — native <dialog> open trigger contract."""

from contracts._kit import DomContract, Node, Present

DOM_CONTRACT = DomContract(
    part="dialog",
    root="[data-dz-dialog-open]",
    nodes=(Node("[data-dz-dialog-open]", attrs={"data-dz-dialog-open": Present()}),),
)

__all__ = ["DOM_CONTRACT"]
```

## Notes

**Pick:** modal addressing — authored shell by id (stem chrome-vs-protocol). Not request gating (confirm = hx-confirm singleton). Opening is the only scripted behaviour (dz-dialog.js → showModal() for [data-dz-dialog-open]); closing is native. Put actions on footer buttons (hx-* / form submit / returnValue).

## Source files

- `site/registry.py` (partial + exchanges + guidance)
- `contracts/dialog.py`
- `controllers/dz-dialog.js`