diff --git a/docs/kit/json-render.md b/docs/kit/json-render.md
index 1c546c5c..ab2ef345 100644
--- a/docs/kit/json-render.md
+++ b/docs/kit/json-render.md
@@ -259,7 +259,7 @@ Container with an optional title and collapsible behavior.
 
 | Prop | Type | Default | Description |
 |------|------|---------|-------------|
-| `title` | `string` | — | Header title |
+| `title` | `string` | — | Header title. A collapsible card still shows its (empty) header without one — otherwise there'd be nothing to click |
 | `collapsible` | `boolean` | `false` | Whether the card can be collapsed |
 | `defaultCollapsed` | `boolean` | `false` | Start collapsed (when `collapsible`) |
 | `loading` | `boolean` | `false` | Show a loading state |
diff --git a/packages/core/src/client/webcomponents/index.ts b/packages/core/src/client/webcomponents/index.ts
index 6ae4c366..93c81230 100644
--- a/packages/core/src/client/webcomponents/index.ts
+++ b/packages/core/src/client/webcomponents/index.ts
@@ -8,6 +8,7 @@ export * from './components/DockStandalone'
 export type {
   BadgeProps,
   ButtonProps,
+  CardProps,
   CodeBlockProps,
   DataTableColumn,
   DataTableProps,
diff --git a/packages/core/src/client/webcomponents/json-render/JsonRender.stories.ts b/packages/core/src/client/webcomponents/json-render/JsonRender.stories.ts
index 8e6a4eb7..f75e618c 100644
--- a/packages/core/src/client/webcomponents/json-render/JsonRender.stories.ts
+++ b/packages/core/src/client/webcomponents/json-render/JsonRender.stories.ts
@@ -82,29 +82,35 @@ export const Gallery: Story = {
 }
 
 /**
- * A `Card` grouping content under a titled, bordered surface. Toggle the
- * Controls below to compare today's default (`primary`, non-`interactive` —
- * unchanged from before this fix) against the new opt-in look: `variant`
+ * A `Card` grouping content under a titled, bordered surface. `variant`
  * tints the background (`secondary`/`danger`) or leaves it untouched
- * (`primary`/`ghost`); `interactive` strengthens the Card's border on hover
- * and tints each row's (`Stack`) background on hover.
+ * (`primary`/`ghost`); `interactive` strengthens the border on hover and
+ * tints each row's (`Stack`) background. `collapsible` + `defaultCollapsed`
+ * control the initial collapse state; clear `title` to confirm the header
+ * (and its chevron) still renders without one.
  */
 interface CardArgs {
   variant: 'primary' | 'secondary' | 'ghost' | 'danger'
   interactive: boolean
+  title: string
+  collapsible: boolean
+  defaultCollapsed: boolean
 }
 
 export const Card: StoryObj<Meta<CardArgs>> = {
   argTypes: {
     variant: { control: 'select', options: ['primary', 'secondary', 'ghost', 'danger'] },
     interactive: { control: 'boolean' },
+    title: { control: 'text' },
+    collapsible: { control: 'boolean' },
+    defaultCollapsed: { control: 'boolean' },
   },
-  args: { variant: 'primary', interactive: false },
+  args: { variant: 'primary', interactive: false, title: 'Plugin', collapsible: true, defaultCollapsed: false },
   render: args => renderSpec(() => ({
     root: 'root',
     state: {},
     elements: {
-      root: { type: 'Card', props: { title: 'Plugin', collapsible: false, variant: args.variant, interactive: args.interactive }, children: ['body'] },
+      root: { type: 'Card', props: { title: args.title, collapsible: args.collapsible, defaultCollapsed: args.defaultCollapsed, variant: args.variant, interactive: args.interactive }, children: ['body'] },
       body: { type: 'Stack', props: { direction: 'column', gap: 4, padding: 4 }, children: ['row1', 'row2'] },
       row1: { type: 'Stack', props: { direction: 'row', gap: 8, align: 'center', interactive: args.interactive }, children: ['t', 'badge'] },
       t: { type: 'Text', props: { text: 'vite-plugin-inspect', variant: 'code' } },
diff --git a/packages/core/src/client/webcomponents/json-render/components/Card.ts b/packages/core/src/client/webcomponents/json-render/components/Card.ts
index aa6a092d..45b5b0f1 100644
--- a/packages/core/src/client/webcomponents/json-render/components/Card.ts
+++ b/packages/core/src/client/webcomponents/json-render/components/Card.ts
@@ -1,11 +1,21 @@
-import type { RegistryComponentProps } from './types'
 import { defineComponent, h, ref } from 'vue'
 import { border, borderSolid, borderStrong, colors, surfaceMuted } from './tokens'
+import { registryProps } from './types'
+
+export type CardVariant = 'primary' | 'secondary' | 'ghost' | 'danger'
+
+export interface CardProps {
+  title?: string
+  collapsible?: boolean
+  defaultCollapsed?: boolean
+  variant?: CardVariant
+  interactive?: boolean
+}
 
 // Mirrors `ContainerCard.vue`'s (packages/ui) opt-in `variant` model: `primary`
 // (default) keeps today's fully transparent look, so existing specs render
 // unchanged; `ghost` is the same no-fill look under a more intentional name.
-const variantBackground: Record<string, string | undefined> = {
+const variantBackground: Record<CardVariant, string | undefined> = {
   primary: undefined,
   secondary: surfaceMuted,
   ghost: undefined,
@@ -14,11 +24,16 @@ const variantBackground: Record<string, string | undefined> = {
 
 export const Card = defineComponent({
   name: 'JrCard',
-  props: ['element', 'emit', 'on', 'bindings', 'loading'],
-  setup(ctx: RegistryComponentProps, { slots }) {
-    const collapsed = ref(false)
+  props: registryProps<'Card', CardProps>(),
+  setup(ctx, { slots }) {
+    const collapsed = ref(!!ctx.element.props.defaultCollapsed)
     return () => {
       const { title, collapsible, variant = 'primary', interactive = false } = ctx.element.props
+      const toggle = ctx.on('toggle')
+      const setCollapsed = (next: boolean) => {
+        collapsed.value = next
+        toggle.emit()
+      }
       return h('div', {
         class: 'jr-card',
         style: {
@@ -34,7 +49,8 @@ export const Card = defineComponent({
         onMouseenter: interactive ? (e: MouseEvent) => { (e.currentTarget as HTMLElement).style.borderColor = borderStrong } : undefined,
         onMouseleave: interactive ? (e: MouseEvent) => { (e.currentTarget as HTMLElement).style.borderColor = border } : undefined,
       }, [
-        title && h('div', {
+        // Renders without a `title` too — a collapsible card needs this as its click target.
+        (title || collapsible) && h('div', {
           class: 'jr-card-header',
           style: {
             padding: '8px 12px',
@@ -47,7 +63,7 @@ export const Card = defineComponent({
             borderBottom: collapsed.value ? 'none' : borderSolid(border),
             userSelect: 'none',
           },
-          onClick: collapsible ? () => { collapsed.value = !collapsed.value } : undefined,
+          onClick: collapsible ? () => setCollapsed(!collapsed.value) : undefined,
         }, [
           h('span', title),
           collapsible && h('span', {
diff --git a/packages/core/src/client/webcomponents/json-render/registry.ts b/packages/core/src/client/webcomponents/json-render/registry.ts
index bd21fa75..71350645 100644
--- a/packages/core/src/client/webcomponents/json-render/registry.ts
+++ b/packages/core/src/client/webcomponents/json-render/registry.ts
@@ -30,6 +30,7 @@ export { UnsupportedComponent }
  */
 export type { BadgeProps } from './components/Badge'
 export type { ButtonProps } from './components/Button'
+export type { CardProps } from './components/Card'
 export type { CodeBlockProps } from './components/CodeBlock'
 export type { DataTableColumn, DataTableProps } from './components/DataTable'
 export type { DividerProps } from './components/Divider'
diff --git a/test/__snapshots__/tsnapi/@vitejs/devtools/client/webcomponents.snapshot.d.ts b/test/__snapshots__/tsnapi/@vitejs/devtools/client/webcomponents.snapshot.d.ts
index ed75e479..31763207 100644
--- a/test/__snapshots__/tsnapi/@vitejs/devtools/client/webcomponents.snapshot.d.ts
+++ b/test/__snapshots__/tsnapi/@vitejs/devtools/client/webcomponents.snapshot.d.ts
@@ -14,6 +14,13 @@ export interface ButtonProps {
   icon?: string;
   disabled?: boolean;
 }
+export interface CardProps {
+  title?: string;
+  collapsible?: boolean;
+  defaultCollapsed?: boolean;
+  variant?: CardVariant;
+  interactive?: boolean;
+}
 export interface CodeBlockProps {
   code?: string;
   filename?: string;