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+---
+name: htmx-patterns
+description: HTMX conventions — default attributes, form patterns, validation errors, hypermedia-first API design. Use when writing HTMX templates or Go handlers that return HTML fragments.
+---
+
+# HTMX patterns
+
+## Default attributes
+Always include on interactive elements:
+- `hx-indicator` for loading states
+- `hx-swap="innerHTML"` as default (explicit over implicit)
+- `hx-target` pointing to a specific ID, never `this` in production
+
+## Form pattern
+```html
+<form hx-post="/items" hx-target="#item-list" hx-swap="beforeend" hx-indicator="#spinner">
+  <input type="text" name="title" required>
+  <button type="submit">Add</button>
+  <span id="spinner" class="htmx-indicator">...</span>
+</form>
+```
+
+## Server-sent validation errors
+Return 422 with the error fragment, swap into the form's error container:
+```html
+hx-target-422="#form-errors"
+```
+
+## Prefer hypermedia over JSON
+If the endpoint returns data for display, return an HTML fragment.
+Only use JSON for machine-to-machine APIs or when a non-browser client needs it.