diff --git a/change/@fluentui-babel-preset-storybook-full-source-perstory.json b/change/@fluentui-babel-preset-storybook-full-source-perstory.json
new file mode 100644
index 00000000000000..932cbe90f121d6
--- /dev/null
+++ b/change/@fluentui-babel-preset-storybook-full-source-perstory.json
@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "feat: add opt-in `storyGranularity: 'story'` mode that emits a per-story sliced `fullSource` for files with multiple story exports",
+  "packageName": "@fluentui/babel-preset-storybook-full-source",
+  "email": "martinhochel@microsoft.com",
+  "dependentChangeType": "patch"
+}
diff --git a/packages/react-components/babel-preset-storybook-full-source/README.md b/packages/react-components/babel-preset-storybook-full-source/README.md
index 279ba6b29dc16c..389e0a1945ca14 100644
--- a/packages/react-components/babel-preset-storybook-full-source/README.md
+++ b/packages/react-components/babel-preset-storybook-full-source/README.md
@@ -19,6 +19,7 @@ To use this Babel preset, add it to your Babel configuration:
 - **Removes Storybook specific assignments**: Avoids issues with undefined stories and unnecessary clutter.
 - **Collects and modifies import declarations**: Ensures valid single-file code examples.
 - **Adds the `context.parameters.fullSource` property**: post-processed, single-file source for the "Open in Sandbox" flow.
+- **Per-story source** (opt-in via `storyGranularity: 'story'`): when a story file contains multiple story exports (the standard Component Story Format convention), each story gets its **own** sliced `fullSource` containing only the imports and helper declarations it references, plus that single story converted to a renderable function. CSF3 object stories (`{ render }`, or `args`-only stories rendered via the meta `component`) and spread stories (`{ ...Base }`) are supported. Capitalized non-story exports (e.g. shared data objects) are ignored — only genuine story-shaped exports are emitted. `play`/`parameters` are omitted from the generated sample (source files are never modified). Defaults to `'file'`, which attaches the whole file to the last story export (suited to the one-story-per-file convention).
 - **CSS module support** (opt-in via `cssModules` option): when enabled, reads `*.module.css` files from disk and injects `context.parameters.cssModuleSources` with `{ cssModules, tokensSource }` entries for the sandbox addon and docs panel. Set `cssModules: true` to enable, or `cssModules: { tokensFilePath: '...' }` to also inject a tokens CSS file as `tokensSource`.
 
 ## Note
diff --git a/packages/react-components/babel-preset-storybook-full-source/etc/babel-preset-storybook-full-source.api.md b/packages/react-components/babel-preset-storybook-full-source/etc/babel-preset-storybook-full-source.api.md
index 9a5d9239071e6c..a4778b72e27b40 100644
--- a/packages/react-components/babel-preset-storybook-full-source/etc/babel-preset-storybook-full-source.api.md
+++ b/packages/react-components/babel-preset-storybook-full-source/etc/babel-preset-storybook-full-source.api.md
@@ -10,6 +10,7 @@ import * as Babel from '@babel/core';
 export interface BabelPluginOptions {
     cssModules?: boolean | CssModulesConfig;
     importMappings: Record<string, DependencyEntry>;
+    storyGranularity?: 'file' | 'story';
 }
 
 // @public
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-data-export/code.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-data-export/code.js
new file mode 100644
index 00000000000000..4644963ef98690
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-data-export/code.js
@@ -0,0 +1,20 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+
+const meta = {
+  title: 'Button',
+  component: Button,
+};
+
+export default meta;
+
+// Genuine story — should get a sliced fullSource.
+export const Default = {
+  render: () => <Button>Default</Button>,
+};
+
+// Capitalized data export (not a story) — must NOT be turned into a fake story.
+export const BrandColors = {
+  primary: '#0f6cbd',
+  danger: '#c50f1f',
+};
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-data-export/output.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-data-export/output.js
new file mode 100644
index 00000000000000..8ec3e8db9d8b23
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-data-export/output.js
@@ -0,0 +1,21 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+const meta = {
+  title: 'Button',
+  component: Button,
+};
+export default meta;
+
+// Genuine story — should get a sliced fullSource.
+export const Default = {
+  render: () => /*#__PURE__*/ React.createElement(Button, null, 'Default'),
+};
+
+// Capitalized data export (not a story) — must NOT be turned into a fake story.
+export const BrandColors = {
+  primary: '#0f6cbd',
+  danger: '#c50f1f',
+};
+Default.parameters = {};
+Default.parameters.fullSource =
+  'import { Button } from "@fluentui/react-components";\nimport * as React from "react";\n\n// Genuine story \u2014 should get a sliced fullSource.\nexport const Default = () => <Button>Default</Button>;\n';
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-render-and-args/code.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-render-and-args/code.js
new file mode 100644
index 00000000000000..180dfec1d23ee1
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-render-and-args/code.js
@@ -0,0 +1,39 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+
+const meta = {
+  title: 'Button',
+  component: Button,
+  args: {
+    appearance: 'primary',
+  },
+};
+
+export default meta;
+
+export const Default = {
+  render: () => <Button>Default</Button>,
+};
+
+export const WithArgs = {
+  args: {
+    appearance: 'outline',
+  },
+  render: args => <Button {...args}>With args</Button>,
+};
+
+export const ArgsOnly = {
+  args: {
+    children: 'Args only',
+  },
+  play: async () => {
+    /* interaction test - must not leak into fullSource */
+  },
+  parameters: {
+    docs: {
+      description: {
+        story: 'Rendered purely from args.',
+      },
+    },
+  },
+};
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-render-and-args/output.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-render-and-args/output.js
new file mode 100644
index 00000000000000..f5c9c1582049d9
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-render-and-args/output.js
@@ -0,0 +1,43 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+const meta = {
+  title: 'Button',
+  component: Button,
+  args: {
+    appearance: 'primary',
+  },
+};
+export default meta;
+export const Default = {
+  render: () => /*#__PURE__*/ React.createElement(Button, null, 'Default'),
+};
+export const WithArgs = {
+  args: {
+    appearance: 'outline',
+  },
+  render: args => /*#__PURE__*/ React.createElement(Button, args, 'With args'),
+};
+export const ArgsOnly = {
+  args: {
+    children: 'Args only',
+  },
+  play: async () => {
+    /* interaction test - must not leak into fullSource */
+  },
+  parameters: {
+    docs: {
+      description: {
+        story: 'Rendered purely from args.',
+      },
+    },
+  },
+};
+Default.parameters = {};
+Default.parameters.fullSource =
+  'import { Button } from "@fluentui/react-components";\nimport * as React from "react";\nexport const Default = () => <Button>Default</Button>;\n';
+WithArgs.parameters = {};
+WithArgs.parameters.fullSource =
+  'import { Button } from "@fluentui/react-components";\nimport * as React from "react";\nexport const WithArgs = () => {\n  const args = { appearance: "outline" };\n  return <Button {...args}>With args</Button>;\n};\n';
+ArgsOnly.parameters = {};
+ArgsOnly.parameters.fullSource =
+  'import { Button } from "@fluentui/react-components";\nimport * as React from "react";\nexport const ArgsOnly = () => {\n  const args = { appearance: "primary", children: "Args only" };\n  return <Button {...args} />;\n};\n';
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-spread/code.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-spread/code.js
new file mode 100644
index 00000000000000..053fa32aafe225
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-spread/code.js
@@ -0,0 +1,24 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+
+const meta = {
+  title: 'Button',
+  component: Button,
+};
+
+export default meta;
+
+export const Base = {
+  render: () => <Button appearance="primary">Base</Button>,
+};
+
+export const Derived = {
+  ...Base,
+  parameters: {
+    docs: {
+      description: {
+        story: 'Spreads Base.',
+      },
+    },
+  },
+};
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-spread/output.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-spread/output.js
new file mode 100644
index 00000000000000..0952f8d44e023c
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/csf3-spread/output.js
@@ -0,0 +1,33 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+const meta = {
+  title: 'Button',
+  component: Button,
+};
+export default meta;
+export const Base = {
+  render: () =>
+    /*#__PURE__*/ React.createElement(
+      Button,
+      {
+        appearance: 'primary',
+      },
+      'Base',
+    ),
+};
+export const Derived = {
+  ...Base,
+  parameters: {
+    docs: {
+      description: {
+        story: 'Spreads Base.',
+      },
+    },
+  },
+};
+Base.parameters = {};
+Base.parameters.fullSource =
+  'import { Button } from "@fluentui/react-components";\nimport * as React from "react";\nexport const Base = () => <Button appearance="primary">Base</Button>;\n';
+Derived.parameters = {};
+Derived.parameters.fullSource =
+  'import { Button } from "@fluentui/react-components";\nimport * as React from "react";\nexport const Derived = () => <Button appearance="primary">Base</Button>;\n';
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf2/code.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf2/code.js
new file mode 100644
index 00000000000000..276358c6ed769b
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf2/code.js
@@ -0,0 +1,12 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+
+const Wrapper = ({ children }) => <div className="wrapper">{children}</div>;
+
+export const Primary = () => (
+  <Wrapper>
+    <Button appearance="primary">Primary</Button>
+  </Wrapper>
+);
+
+export const Secondary = () => <Button appearance="secondary">Secondary</Button>;
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf2/output.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf2/output.js
new file mode 100644
index 00000000000000..2f1eaa0bc295de
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf2/output.js
@@ -0,0 +1,36 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+const Wrapper = ({ children }) =>
+  /*#__PURE__*/ React.createElement(
+    'div',
+    {
+      className: 'wrapper',
+    },
+    children,
+  );
+export const Primary = () =>
+  /*#__PURE__*/ React.createElement(
+    Wrapper,
+    null,
+    /*#__PURE__*/ React.createElement(
+      Button,
+      {
+        appearance: 'primary',
+      },
+      'Primary',
+    ),
+  );
+export const Secondary = () =>
+  /*#__PURE__*/ React.createElement(
+    Button,
+    {
+      appearance: 'secondary',
+    },
+    'Secondary',
+  );
+Primary.parameters = {};
+Primary.parameters.fullSource =
+  'import { Button } from "@fluentui/react-components";\nimport * as React from "react";\n\nconst Wrapper = ({ children }) => <div className="wrapper">{children}</div>;\n\nexport const Primary = () => (\n  <Wrapper>\n    <Button appearance="primary">Primary</Button>\n  </Wrapper>\n);\n';
+Secondary.parameters = {};
+Secondary.parameters.fullSource =
+  'import { Button } from "@fluentui/react-components";\nimport * as React from "react";\n\nexport const Secondary = () => (\n  <Button appearance="secondary">Secondary</Button>\n);\n';
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf3/code.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf3/code.js
new file mode 100644
index 00000000000000..5cb7bce5e812f5
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf3/code.js
@@ -0,0 +1,48 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+
+const meta = {
+  title: 'Card',
+  component: Button,
+};
+
+export default meta;
+
+// --- Custom React components defined in the module ---
+const Card = ({ children }) => <div className="card">{children}</div>;
+
+const CardHeader = ({ title }) => <h3 className="card-header">{title}</h3>;
+
+const CardMedia = ({ src }) => <img className="card-media" src={src} alt="" />;
+
+const CardFooter = () => <footer className="card-footer">© Contoso</footer>;
+
+// Uses Card + CardHeader + Button.
+export const Basic = {
+  render: () => (
+    <Card>
+      <CardHeader title="Basic" />
+      <Button>Action</Button>
+    </Card>
+  ),
+};
+
+// Uses Card + CardMedia only.
+export const WithMedia = {
+  render: () => (
+    <Card>
+      <CardMedia src="cat.png" />
+    </Card>
+  ),
+};
+
+// Uses Card + CardHeader + CardMedia + CardFooter.
+export const Full = {
+  render: () => (
+    <Card>
+      <CardHeader title="Full" />
+      <CardMedia src="dog.png" />
+      <CardFooter />
+    </Card>
+  ),
+};
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf3/output.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf3/output.js
new file mode 100644
index 00000000000000..00b1ef7e2d08ce
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-csf3/output.js
@@ -0,0 +1,89 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+const meta = {
+  title: 'Card',
+  component: Button,
+};
+export default meta;
+
+// --- Custom React components defined in the module ---
+const Card = ({ children }) =>
+  /*#__PURE__*/ React.createElement(
+    'div',
+    {
+      className: 'card',
+    },
+    children,
+  );
+const CardHeader = ({ title }) =>
+  /*#__PURE__*/ React.createElement(
+    'h3',
+    {
+      className: 'card-header',
+    },
+    title,
+  );
+const CardMedia = ({ src }) =>
+  /*#__PURE__*/ React.createElement('img', {
+    className: 'card-media',
+    src: src,
+    alt: '',
+  });
+const CardFooter = () =>
+  /*#__PURE__*/ React.createElement(
+    'footer',
+    {
+      className: 'card-footer',
+    },
+    '\xA9 Contoso',
+  );
+
+// Uses Card + CardHeader + Button.
+export const Basic = {
+  render: () =>
+    /*#__PURE__*/ React.createElement(
+      Card,
+      null,
+      /*#__PURE__*/ React.createElement(CardHeader, {
+        title: 'Basic',
+      }),
+      /*#__PURE__*/ React.createElement(Button, null, 'Action'),
+    ),
+};
+
+// Uses Card + CardMedia only.
+export const WithMedia = {
+  render: () =>
+    /*#__PURE__*/ React.createElement(
+      Card,
+      null,
+      /*#__PURE__*/ React.createElement(CardMedia, {
+        src: 'cat.png',
+      }),
+    ),
+};
+
+// Uses Card + CardHeader + CardMedia + CardFooter.
+export const Full = {
+  render: () =>
+    /*#__PURE__*/ React.createElement(
+      Card,
+      null,
+      /*#__PURE__*/ React.createElement(CardHeader, {
+        title: 'Full',
+      }),
+      /*#__PURE__*/ React.createElement(CardMedia, {
+        src: 'dog.png',
+      }),
+      /*#__PURE__*/ React.createElement(CardFooter, null),
+    ),
+};
+Basic.parameters = {};
+Basic.parameters.fullSource =
+  'import { Button } from "@fluentui/react-components";\nimport * as React from "react";\n\n// --- Custom React components defined in the module ---\nconst Card = ({ children }) => <div className="card">{children}</div>;\n\nconst CardHeader = ({ title }) => <h3 className="card-header">{title}</h3>;\n\n// Uses Card + CardHeader + Button.\nexport const Basic = () => (\n  <Card>\n    <CardHeader title="Basic" />\n    <Button>Action</Button>\n  </Card>\n);\n';
+WithMedia.parameters = {};
+WithMedia.parameters.fullSource =
+  'import * as React from "react";\n\n// --- Custom React components defined in the module ---\nconst Card = ({ children }) => <div className="card">{children}</div>;\n\nconst CardMedia = ({ src }) => <img className="card-media" src={src} alt="" />;\n\n// Uses Card + CardMedia only.\nexport const WithMedia = () => (\n  <Card>\n    <CardMedia src="cat.png" />\n  </Card>\n);\n';
+Full.parameters = {};
+Full.parameters.fullSource =
+  'import * as React from "react";\n\n// --- Custom React components defined in the module ---\nconst Card = ({ children }) => <div className="card">{children}</div>;\n\nconst CardHeader = ({ title }) => <h3 className="card-header">{title}</h3>;\n\nconst CardMedia = ({ src }) => <img className="card-media" src={src} alt="" />;\n\nconst CardFooter = () => <footer className="card-footer">\xA9 Contoso</footer>;\n\n// Uses Card + CardHeader + CardMedia + CardFooter.\nexport const Full = () => (\n  <Card>\n    <CardHeader title="Full" />\n    <CardMedia src="dog.png" />\n    <CardFooter />\n  </Card>\n);\n';
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-typescript/code.tsx b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-typescript/code.tsx
new file mode 100644
index 00000000000000..2d1f7784be12d4
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-typescript/code.tsx
@@ -0,0 +1,45 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+import type { ButtonProps } from '@fluentui/react-button';
+
+const meta = {
+  title: 'Card',
+  component: Button,
+};
+
+export default meta;
+
+// --- Custom components with TypeScript types ---
+
+type CardProps = {
+  title: string;
+  children: React.ReactNode;
+};
+
+const Card: React.FC<CardProps> = ({ title, children }) => (
+  <section>
+    <h3>{title}</h3>
+    {children}
+  </section>
+);
+
+interface ActionProps {
+  label: string;
+  appearance?: ButtonProps['appearance'];
+}
+
+const Action: React.FC<ActionProps> = ({ label, appearance }) => <Button appearance={appearance}>{label}</Button>;
+
+// Uses `Card` (+ `CardProps`) only — must NOT include `Action`/`ActionProps`/`ButtonProps`.
+export const Simple = {
+  render: () => (
+    <Card title="Simple">
+      <p>Content</p>
+    </Card>
+  ),
+};
+
+// Uses `Action` (+ `ActionProps` + `ButtonProps` type import) — must NOT include `Card`/`CardProps`.
+export const WithAction = {
+  render: () => <Action label="Go" appearance="primary" />,
+};
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-typescript/options.json b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-typescript/options.json
new file mode 100644
index 00000000000000..d3628b60918878
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-typescript/options.json
@@ -0,0 +1,3 @@
+{
+  "fixtureOutputExt": ".js"
+}
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-typescript/output.js b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-typescript/output.js
new file mode 100644
index 00000000000000..76c36d526d65c7
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/__fixtures__/storybook-stories-fullsource-per-story/multi-story-typescript/output.js
@@ -0,0 +1,47 @@
+import * as React from 'react';
+import { Button } from '@fluentui/react-button';
+const meta = {
+  title: 'Card',
+  component: Button,
+};
+export default meta;
+
+// --- Custom components with TypeScript types ---
+
+const Card = ({ title, children }) =>
+  /*#__PURE__*/ React.createElement('section', null, /*#__PURE__*/ React.createElement('h3', null, title), children);
+const Action = ({ label, appearance }) =>
+  /*#__PURE__*/ React.createElement(
+    Button,
+    {
+      appearance: appearance,
+    },
+    label,
+  );
+
+// Uses `Card` (+ `CardProps`) only — must NOT include `Action`/`ActionProps`/`ButtonProps`.
+export const Simple = {
+  render: () =>
+    /*#__PURE__*/ React.createElement(
+      Card,
+      {
+        title: 'Simple',
+      },
+      /*#__PURE__*/ React.createElement('p', null, 'Content'),
+    ),
+};
+
+// Uses `Action` (+ `ActionProps` + `ButtonProps` type import) — must NOT include `Card`/`CardProps`.
+export const WithAction = {
+  render: () =>
+    /*#__PURE__*/ React.createElement(Action, {
+      label: 'Go',
+      appearance: 'primary',
+    }),
+};
+Simple.parameters = {};
+Simple.parameters.fullSource =
+  'import * as React from "react";\n\n// --- Custom components with TypeScript types ---\n\ntype CardProps = {\n  title: string;\n  children: React.ReactNode;\n};\n\nconst Card: React.FC<CardProps> = ({ title, children }) => (\n  <section>\n    <h3>{title}</h3>\n    {children}\n  </section>\n);\n\n// Uses `Card` (+ `CardProps`) only \u2014 must NOT include `Action`/`ActionProps`/`ButtonProps`.\nexport const Simple = () => (\n  <Card title="Simple">\n    <p>Content</p>\n  </Card>\n);\n';
+WithAction.parameters = {};
+WithAction.parameters.fullSource =
+  'import { Button, ButtonProps } from "@fluentui/react-components";\nimport * as React from "react";\n\ninterface ActionProps {\n  label: string;\n  appearance?: ButtonProps["appearance"];\n}\n\nconst Action: React.FC<ActionProps> = ({ label, appearance }) => (\n  <Button appearance={appearance}>{label}</Button>\n);\n\n// Uses `Action` (+ `ActionProps` + `ButtonProps` type import) \u2014 must NOT include `Card`/`CardProps`.\nexport const WithAction = () => <Action label="Go" appearance="primary" />;\n';
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/fullsource.test.ts b/packages/react-components/babel-preset-storybook-full-source/src/fullsource.test.ts
index 43af7003784c60..9e5da840b779f9 100644
--- a/packages/react-components/babel-preset-storybook-full-source/src/fullsource.test.ts
+++ b/packages/react-components/babel-preset-storybook-full-source/src/fullsource.test.ts
@@ -41,3 +41,23 @@ pluginTester({
   pluginName: PLUGIN_NAME,
   plugin,
 });
+
+// Per-story granularity: each story export gets its own sliced `fullSource`.
+pluginTester({
+  babelOptions: {
+    // Compile the fixtures like a real Storybook build (JSX + TS stripped). Type
+    // preservation is asserted on the emitted `fullSource` strings, which come
+    // from the plugin's own transform and keep types.
+    presets: ['@babel/preset-react', '@babel/preset-typescript'],
+  },
+  fixtures: path.join(__dirname, '__fixtures__/storybook-stories-fullsource-per-story'),
+  pluginOptions: {
+    importMappings: {
+      '@fluentui/react-button': defaultDependencyReplace,
+      '@fluentui/react-menu': defaultDependencyReplace,
+    },
+    storyGranularity: 'story',
+  },
+  pluginName: PLUGIN_NAME,
+  plugin,
+});
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/fullsource.ts b/packages/react-components/babel-preset-storybook-full-source/src/fullsource.ts
index b9e3046fac49fa..e0221d52b16fb0 100644
--- a/packages/react-components/babel-preset-storybook-full-source/src/fullsource.ts
+++ b/packages/react-components/babel-preset-storybook-full-source/src/fullsource.ts
@@ -5,6 +5,7 @@ import * as nodePath from 'path';
 
 import { modifyImportsPlugin } from './modifyImports';
 import { removeStorybookParameters } from './removeStorybookParameters';
+import { sliceStorySource } from './sliceStory';
 import { BabelPluginOptions } from './types';
 
 export const PLUGIN_NAME = 'storybook-stories-fullsource';
@@ -26,26 +27,30 @@ export function fullSourcePlugin(babel: typeof Babel, options: BabelPluginOption
   const { types: t } = babel;
   const cssModulesConfig = typeof options.cssModules === 'object' ? options.cssModules : undefined;
   const cssModulesEnabled = Boolean(options.cssModules);
+  const granularity = options.storyGranularity ?? 'file';
 
   let storyName: string;
-  let parametersAssignment: Babel.NodePath<Babel.types.AssignmentExpression> | undefined;
+  // All component-like story exports in document order (used by 'story' mode).
+  let storyNames: string[] = [];
+  // Story names that already have a `<Story>.parameters = …` assignment.
+  const storiesWithParameters = new Set<string>();
 
-  const createStoryParametersAssignmentExpression = () => {
+  const createStoryParametersAssignmentExpression = (targetStoryName: string) => {
     const storyParameters = t.assignmentExpression(
       '=',
-      t.memberExpression(t.identifier(storyName), t.identifier('parameters')),
+      t.memberExpression(t.identifier(targetStoryName), t.identifier('parameters')),
       t.objectExpression([]),
     );
 
     return t.expressionStatement(storyParameters);
   };
 
-  const createFullSourceAssignmentExpression = (fullSource: string) => {
+  const createFullSourceAssignmentExpression = (targetStoryName: string, fullSource: string) => {
     return t.expressionStatement(
       t.assignmentExpression(
         '=',
         t.memberExpression(
-          t.memberExpression(t.identifier(storyName), t.identifier('parameters')),
+          t.memberExpression(t.identifier(targetStoryName), t.identifier('parameters')),
           t.identifier('fullSource'),
         ),
         t.stringLiteral(fullSource),
@@ -62,12 +67,15 @@ export function fullSourcePlugin(babel: typeof Babel, options: BabelPluginOption
    *     tokensSource: '…',
    *   });
    */
-  const createCssModuleSourcesAssignment = (data: {
-    cssModules?: Array<{ name: string; source: string }>;
-    tokensSource?: string;
-  }) => {
+  const createCssModuleSourcesAssignment = (
+    targetStoryName: string,
+    data: {
+      cssModules?: Array<{ name: string; source: string }>;
+      tokensSource?: string;
+    },
+  ) => {
     const storyParametersCssModuleSources = t.memberExpression(
-      t.memberExpression(t.identifier(storyName), t.identifier('parameters')),
+      t.memberExpression(t.identifier(targetStoryName), t.identifier('parameters')),
       t.identifier('cssModuleSources'),
     );
 
@@ -112,6 +120,7 @@ export function fullSourcePlugin(babel: typeof Babel, options: BabelPluginOption
           isComponentLikeName(declaration.id.name)
         ) {
           storyName = declaration.id.name;
+          storyNames.push(declaration.id.name);
           return;
         }
 
@@ -123,6 +132,7 @@ export function fullSourcePlugin(babel: typeof Babel, options: BabelPluginOption
           isComponentLikeName(declaration.declarations[0].id.name)
         ) {
           storyName = declaration.declarations[0].id.name;
+          storyNames.push(declaration.declarations[0].id.name);
           return;
         }
       },
@@ -131,52 +141,83 @@ export function fullSourcePlugin(babel: typeof Babel, options: BabelPluginOption
         if (
           t.isMemberExpression(path.node.left) &&
           t.isIdentifier(path.node.left.object) &&
-          path.node.left.object.name === storyName &&
           t.isIdentifier(path.node.left.property) &&
           path.node.left.property.name === 'parameters'
         ) {
-          parametersAssignment = path;
+          storiesWithParameters.add(path.node.left.object.name);
         }
       },
       Program: {
         enter() {
           storyName = '';
-          parametersAssignment = undefined;
+          storyNames = [];
+          storiesWithParameters.clear();
         },
         exit(path, state) {
-          if (!storyName || !state.filename) {
+          if (!state.filename || storyNames.length === 0) {
             return;
           }
 
           const fileContents = fs.readFileSync(state.filename, 'utf-8');
-          const transformedCode = babel.transformSync(fileContents, {
-            ...state.file.opts,
-            compact: false,
-            retainLines: true,
-            comments: false,
-            plugins: [[modifyImportsPlugin, options], removeStorybookParameters],
-          })?.code;
-
-          const code = prettier.format(transformedCode ?? '', { parser: 'babel-ts' });
-
-          if (!parametersAssignment) {
-            path.pushContainer('body', createStoryParametersAssignmentExpression());
-          }
-
-          path.pushContainer('body', createFullSourceAssignmentExpression(code));
-
-          // Auto-detect CSS module imports and inject their source as parameters.
-          // This removes the need for manual `?raw` imports + `withCssModuleSource()` calls.
-          if (cssModulesEnabled) {
-            const cssModules = collectCssModuleImports(path, t, state.filename);
-            const tokensSource = cssModulesConfig?.tokensFilePath
+          const tokensSource =
+            cssModulesEnabled && cssModulesConfig?.tokensFilePath
               ? fs.readFileSync(cssModulesConfig.tokensFilePath, 'utf-8')
               : undefined;
+          // Auto-detected CSS module imports are file-level (identical for every
+          // story), so collect them once and reuse for each emitted story.
+          const cssModules = cssModulesEnabled ? collectCssModuleImports(path, t, state.filename) : [];
+
+          // Runs the shared modify-imports + prettier pipeline over a source string.
+          const buildFullSource = (source: string): string => {
+            const transformed = babel.transformSync(source, {
+              ...state.file.opts,
+              compact: false,
+              retainLines: true,
+              comments: false,
+              plugins: [[modifyImportsPlugin, options], removeStorybookParameters],
+            })?.code;
 
-            if (cssModules.length > 0 || tokensSource) {
-              path.pushContainer('body', createCssModuleSourcesAssignment({ cssModules, tokensSource }));
+            return prettier.format(transformed ?? '', { parser: 'babel-ts' });
+          };
+
+          // Emits `<Story>.parameters` (when missing), `.fullSource` and, when
+          // enabled, `.cssModuleSources` for a single story.
+          const emitStorySource = (currentStory: string, code: string): void => {
+            if (!storiesWithParameters.has(currentStory)) {
+              path.pushContainer('body', createStoryParametersAssignmentExpression(currentStory));
+              storiesWithParameters.add(currentStory);
             }
+
+            path.pushContainer('body', createFullSourceAssignmentExpression(currentStory, code));
+
+            if (cssModulesEnabled && (cssModules.length > 0 || tokensSource)) {
+              path.pushContainer('body', createCssModuleSourcesAssignment(currentStory, { cssModules, tokensSource }));
+            }
+          };
+
+          if (granularity === 'story') {
+            for (const currentStory of storyNames) {
+              const sliced = sliceStorySource(babel, fileContents, {
+                targetStory: currentStory,
+                filename: state.filename,
+              });
+
+              if (!sliced) {
+                continue;
+              }
+
+              emitStorySource(currentStory, buildFullSource(sliced));
+            }
+
+            return;
           }
+
+          // 'file' granularity (default, legacy): the whole file on the last story.
+          if (!storyName) {
+            return;
+          }
+
+          emitStorySource(storyName, buildFullSource(fileContents));
         },
       },
     },
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/sliceStory.ts b/packages/react-components/babel-preset-storybook-full-source/src/sliceStory.ts
new file mode 100644
index 00000000000000..586e4a093511f4
--- /dev/null
+++ b/packages/react-components/babel-preset-storybook-full-source/src/sliceStory.ts
@@ -0,0 +1,731 @@
+import * as Babel from '@babel/core';
+
+/**
+ * Options for {@link sliceStorySource}.
+ */
+export interface SliceStoryOptions {
+  /** Name of the story export to keep (all other stories are removed). */
+  targetStory: string;
+  /** Absolute path of the story file being processed (used by the parser). */
+  filename?: string;
+}
+
+/**
+ * Produces a minimal, single-story source string for a given story export.
+ *
+ * Given a Component Story Format file that contains multiple story exports, this
+ * keeps only the `targetStory` export and the module-level imports / helper
+ * declarations it actually references. The story is normalized into a renderable
+ * function so the output is valid for both the "Show code" panel and the
+ * "Open in Sandbox" flow (which renders the exported story as a component).
+ *
+ * - CSF2 function stories (`export const X = () => <…/>`) are kept as-is.
+ * - CSF3 object stories (`export const X = { render: … }`) are unwrapped into a
+ *   function. Their `args` (merged with the meta's `args`) are re-declared as a
+ *   local `const args` so the render body keeps working.
+ * - CSF3 render-less stories (only `args`) are synthesized into
+ *   `() => { const args = {…}; return <Component {...args} />; }` using the
+ *   `component` referenced by the default export (meta).
+ *
+ * The default export (meta), sibling stories, `play`/`parameters` and any
+ * declaration not reachable from the target story are dropped.
+ *
+ * @returns the sliced source string, or `null` when the story cannot be sliced
+ * (e.g. render-less story without a resolvable meta `component`).
+ */
+export function sliceStorySource(babel: typeof Babel, source: string, options: SliceStoryOptions): string | null {
+  const context = { handled: false };
+
+  const result = babel.transformSync(source, {
+    configFile: false,
+    babelrc: false,
+    filename: options.filename,
+    code: true,
+    ast: false,
+    // Mutate the original AST in place and print with `retainLines` (mirroring
+    // `file` granularity) so retained nodes keep their authored formatting and
+    // the downstream prettier output matches — avoiding cosmetic churn.
+    retainLines: true,
+    // Preserve comments so the sliced source matches `file` granularity output
+    // (comment stripping, if any, happens in the shared downstream pass).
+    comments: true,
+    compact: false,
+    parserOpts: {
+      plugins: ['jsx', 'typescript', 'classProperties', 'objectRestSpread'],
+    },
+    plugins: [createSliceStoryPlugin(babel, options, context)],
+  });
+
+  return context.handled ? result?.code ?? null : null;
+}
+
+function createSliceStoryPlugin(
+  babel: typeof Babel,
+  options: SliceStoryOptions,
+  context: { handled: boolean },
+): Babel.PluginObj {
+  const { types: t } = babel;
+  const { targetStory } = options;
+
+  return {
+    name: 'storybook-stories-slice-story',
+    visitor: {
+      // eslint-disable-next-line @typescript-eslint/naming-convention
+      Program(path) {
+        const body = path.get('body');
+
+        // --- Discovery -------------------------------------------------------
+        let metaObject: Babel.types.ObjectExpression | undefined;
+        let metaLocalName: string | undefined;
+        let targetPath: Babel.NodePath<Babel.types.ExportNamedDeclaration> | undefined;
+        // Map of `const X = {…}` initializers (exported or not) for spread resolution.
+        const objectConstsByName = new Map<string, Babel.types.ObjectExpression>();
+        // Map of local type declarations (`type`/`interface`/`enum`) by name, used
+        // to resolve type references (babel scope bindings don't track type-only decls).
+        const typeDeclsByName = new Map<string, Babel.NodePath>();
+
+        for (const statementPath of body) {
+          collectObjectConst(t, statementPath, objectConstsByName);
+          collectTypeDecl(t, statementPath, typeDeclsByName);
+
+          if (statementPath.isExportDefaultDeclaration()) {
+            const resolved = resolveMetaObject(t, statementPath.node.declaration, body);
+            metaObject = resolved.object;
+            metaLocalName = resolved.localName;
+            continue;
+          }
+
+          if (statementPath.isExportNamedDeclaration()) {
+            const name = getExportedStoryName(t, statementPath.node);
+            if (name === targetStory) {
+              targetPath = statementPath;
+            }
+          }
+        }
+
+        if (!targetPath) {
+          return;
+        }
+
+        const metaComponentName = metaObject ? getMetaComponentName(t, metaObject) : undefined;
+        const metaArgs = metaObject ? getObjectProperty(t, metaObject, 'args') : undefined;
+
+        // --- Normalize the target story into a renderable function ----------
+        const normalized = normalizeStory(t, targetPath.node, {
+          metaArgs: metaArgs && t.isObjectExpression(metaArgs) ? metaArgs : undefined,
+          metaComponentName,
+          objectConstsByName,
+        });
+
+        if (!normalized) {
+          // Cannot produce a renderable function (e.g. render-less without meta component).
+          return;
+        }
+
+        // Replace only when normalization produced a NEW node (CSF3 transforms).
+        // For CSF2 the original node is kept in place so `retainLines` preserves
+        // its authored source formatting.
+        if (normalized !== targetPath.node) {
+          targetPath.replaceWith(normalized);
+        }
+
+        // Rebuild bindings so references introduced by normalization (args,
+        // the meta component) resolve correctly during reachability analysis.
+        path.scope.crawl();
+
+        // --- Reachability from the normalized story --------------------------
+        const neededBindings = collectReachableBindings(path, targetPath, typeDeclsByName);
+
+        // Map each comment to the node it leads, so comments belonging to removed
+        // nodes (e.g. sibling stories) can be dropped instead of leaking onto
+        // retained neighbours (comments are shared as leading/trailing).
+        const commentOwner = new Map<Babel.types.Comment, Babel.types.Node>();
+        path.traverse({
+          enter(nodePath) {
+            for (const comment of nodePath.node.leadingComments ?? []) {
+              if (!commentOwner.has(comment)) {
+                commentOwner.set(comment, nodePath.node);
+              }
+            }
+          },
+        });
+        const removedNodes = new Set<Babel.types.Node>();
+        const remove = (statementPath: Babel.NodePath) => {
+          removedNodes.add(statementPath.node);
+          statementPath.remove();
+        };
+
+        // --- Prune the program body -----------------------------------------
+        for (const statementPath of path.get('body')) {
+          if (statementPath.node === targetPath.node) {
+            continue;
+          }
+
+          if (statementPath.isImportDeclaration()) {
+            pruneImportDeclaration(t, statementPath, neededBindings);
+            continue;
+          }
+
+          if (statementPath.isExportDefaultDeclaration()) {
+            remove(statementPath);
+            continue;
+          }
+
+          // Remove the `const meta = {…}` declaration backing the default export.
+          if (metaLocalName && isDeclarationOf(t, statementPath, metaLocalName)) {
+            remove(statementPath);
+            continue;
+          }
+
+          // Remove sibling story exports.
+          if (statementPath.isExportNamedDeclaration()) {
+            remove(statementPath);
+            continue;
+          }
+
+          // Remove CSF2 story annotations (`Story.parameters = …`, `Story.args = …`).
+          if (isStoryAnnotationAssignment(t, statementPath)) {
+            remove(statementPath);
+            continue;
+          }
+
+          // Keep only declarations reachable from the target story.
+          if (isModuleLevelDeclaration(t, statementPath)) {
+            if (!isDeclarationReachable(statementPath, neededBindings)) {
+              remove(statementPath);
+            }
+            continue;
+          }
+        }
+
+        // Drop comments that belonged to removed nodes but linger on retained ones.
+        if (removedNodes.size > 0) {
+          const keep = (comments: readonly Babel.types.Comment[] | null | undefined) =>
+            comments ? comments.filter(c => !removedNodes.has(commentOwner.get(c) as Babel.types.Node)) : comments;
+          path.traverse({
+            enter(nodePath) {
+              const node = nodePath.node;
+              node.leadingComments = keep(node.leadingComments) as Babel.types.Comment[] | null;
+              node.trailingComments = keep(node.trailingComments) as Babel.types.Comment[] | null;
+              node.innerComments = keep(node.innerComments) as Babel.types.Comment[] | null;
+            },
+          });
+        }
+
+        context.handled = true;
+      },
+    },
+  };
+}
+
+/**
+ * Resolves the meta object expression from a default export declaration, whether
+ * it is inline (`export default {…}`), TS-wrapped (`… satisfies Meta`) or a
+ * reference to a `const meta = {…}` declaration.
+ */
+function resolveMetaObject(
+  t: typeof Babel.types,
+  declaration: Babel.types.ExportDefaultDeclaration['declaration'],
+  body: Array<Babel.NodePath<Babel.types.Node>>,
+): { object?: Babel.types.ObjectExpression; localName?: string } {
+  const unwrapped = unwrapExpression(t, declaration);
+
+  if (t.isObjectExpression(unwrapped)) {
+    return { object: unwrapped };
+  }
+
+  if (t.isIdentifier(unwrapped)) {
+    const localName = unwrapped.name;
+    for (const statementPath of body) {
+      if (statementPath.isVariableDeclaration()) {
+        for (const declarator of statementPath.node.declarations) {
+          if (t.isIdentifier(declarator.id) && declarator.id.name === localName && declarator.init) {
+            const init = unwrapExpression(t, declarator.init);
+            if (t.isObjectExpression(init)) {
+              return { object: init, localName };
+            }
+          }
+        }
+      }
+    }
+    return { localName };
+  }
+
+  return {};
+}
+
+/** Unwraps TS `as`/`satisfies` and parenthesized expressions. */
+function unwrapExpression<T extends Babel.types.Node>(t: typeof Babel.types, node: T): Babel.types.Node {
+  let current: Babel.types.Node = node;
+  while (t.isTSAsExpression(current) || t.isTSSatisfiesExpression(current) || t.isParenthesizedExpression(current)) {
+    current = current.expression;
+  }
+  return current;
+}
+
+/** Returns the exported story identifier name from a named export, if any. */
+function getExportedStoryName(t: typeof Babel.types, node: Babel.types.ExportNamedDeclaration): string | undefined {
+  const declaration = node.declaration;
+
+  if (t.isFunctionDeclaration(declaration) && t.isIdentifier(declaration.id)) {
+    return isComponentLikeName(declaration.id.name) ? declaration.id.name : undefined;
+  }
+
+  if (t.isVariableDeclaration(declaration) && declaration.declarations.length === 1) {
+    const id = declaration.declarations[0].id;
+    if (t.isIdentifier(id) && isComponentLikeName(id.name)) {
+      return id.name;
+    }
+  }
+
+  return undefined;
+}
+
+/** Reads the `component` identifier name from a meta object expression. */
+function getMetaComponentName(t: typeof Babel.types, metaObject: Babel.types.ObjectExpression): string | undefined {
+  const component = getObjectProperty(t, metaObject, 'component');
+  return component && t.isIdentifier(component) ? component.name : undefined;
+}
+
+/** Reads a property value from an object expression by key. */
+function getObjectProperty(
+  t: typeof Babel.types,
+  object: Babel.types.ObjectExpression,
+  key: string,
+): Babel.types.Expression | undefined {
+  for (const property of object.properties) {
+    if (t.isObjectProperty(property) && !property.computed) {
+      const propKey = property.key;
+      const name = t.isIdentifier(propKey) ? propKey.name : t.isStringLiteral(propKey) ? propKey.value : undefined;
+      if (name === key && t.isExpression(property.value)) {
+        return property.value;
+      }
+    }
+  }
+  return undefined;
+}
+
+interface NormalizeContext {
+  metaArgs?: Babel.types.ObjectExpression;
+  metaComponentName?: string;
+  objectConstsByName: Map<string, Babel.types.ObjectExpression>;
+}
+
+/**
+ * Normalizes a story export into a renderable function export. Returns the new
+ * export node, or `null` when normalization is not possible.
+ */
+function normalizeStory(
+  t: typeof Babel.types,
+  node: Babel.types.ExportNamedDeclaration,
+  context: NormalizeContext,
+): Babel.types.ExportNamedDeclaration | null {
+  const declaration = node.declaration;
+
+  // CSF2 function declaration: `export function X() {…}` — already renderable.
+  if (t.isFunctionDeclaration(declaration)) {
+    return node;
+  }
+
+  if (!t.isVariableDeclaration(declaration) || declaration.declarations.length !== 1) {
+    return null;
+  }
+
+  const declarator = declaration.declarations[0];
+  if (!t.isIdentifier(declarator.id) || !declarator.init) {
+    return null;
+  }
+
+  const id = declarator.id;
+  const storyName = id.name;
+  const init = unwrapExpression(t, declarator.init);
+
+  // CSF2 function story: `export const X = () => <…/>` — already renderable.
+  // Keep the original node so `retainLines` preserves its authored formatting;
+  // only drop a story-type annotation whose type import gets pruned.
+  if (t.isArrowFunctionExpression(init) || t.isFunctionExpression(init)) {
+    if (id.typeAnnotation) {
+      id.typeAnnotation = null;
+    }
+    return node;
+  }
+
+  // CSF3 object story.
+  if (t.isObjectExpression(init)) {
+    const flattened = flattenObjectExpression(t, init, context.objectConstsByName, new Set());
+    const renderProp = getObjectProperty(t, flattened, 'render');
+    const storyArgs = getObjectProperty(t, flattened, 'args');
+    const mergedArgs = mergeArgs(t, context.metaArgs, t.isObjectExpression(storyArgs) ? storyArgs : undefined);
+
+    if (renderProp && (t.isArrowFunctionExpression(renderProp) || t.isFunctionExpression(renderProp))) {
+      const fn = buildRenderFunction(t, renderProp, mergedArgs);
+      return buildFunctionStoryExport(t, storyName, fn);
+    }
+
+    // Render-less args-only story: synthesize `<Component {...args} />`.
+    // Only do this for genuine story objects (empty, or containing only known
+    // CSF fields) so arbitrary capitalized data exports are not turned into
+    // fake stories.
+    if (context.metaComponentName && isStoryShapedObject(t, flattened)) {
+      const fn = buildSynthesizedFunction(t, context.metaComponentName, mergedArgs);
+      return buildFunctionStoryExport(t, storyName, fn);
+    }
+  }
+
+  return null;
+}
+
+/**
+ * Known Component Story Format story-object fields. An object export is treated
+ * as a story only if it is empty or every own property is one of these (or a
+ * spread), avoiding false positives on capitalized data exports.
+ */
+const CSF_STORY_FIELDS = new Set([
+  'render',
+  'args',
+  'argTypes',
+  'play',
+  'parameters',
+  'decorators',
+  'loaders',
+  'tags',
+  'name',
+  'globals',
+  'beforeEach',
+  'story',
+]);
+
+/** Whether an object expression looks like a CSF story object (not arbitrary data). */
+function isStoryShapedObject(t: typeof Babel.types, object: Babel.types.ObjectExpression): boolean {
+  return object.properties.every(property => {
+    if (t.isSpreadElement(property)) {
+      return true;
+    }
+    if ((t.isObjectProperty(property) || t.isObjectMethod(property)) && !property.computed) {
+      const key = property.key;
+      const name = t.isIdentifier(key) ? key.name : t.isStringLiteral(key) ? key.value : undefined;
+      return name !== undefined && CSF_STORY_FIELDS.has(name);
+    }
+    return false;
+  });
+}
+
+/** Builds `export const <name> = <fn>;`. */
+function buildFunctionStoryExport(
+  t: typeof Babel.types,
+  name: string,
+  fn: Babel.types.ArrowFunctionExpression | Babel.types.FunctionExpression,
+): Babel.types.ExportNamedDeclaration {
+  const declarator = t.variableDeclarator(t.identifier(name), fn);
+  return t.exportNamedDeclaration(t.variableDeclaration('const', [declarator]), []);
+}
+
+/**
+ * Converts a story `render` function into a no-arg render function, re-declaring
+ * the args parameter as a local `const` bound to the merged args object.
+ */
+function buildRenderFunction(
+  t: typeof Babel.types,
+  render: Babel.types.ArrowFunctionExpression | Babel.types.FunctionExpression,
+  mergedArgs: Babel.types.ObjectExpression | undefined,
+): Babel.types.ArrowFunctionExpression {
+  const argsParam = render.params[0];
+  const body = render.body;
+
+  // No args parameter — keep the body as-is.
+  if (!argsParam) {
+    return t.arrowFunctionExpression([], body);
+  }
+
+  const argsDeclaration = t.variableDeclaration('const', [
+    t.variableDeclarator(argsParam as Babel.types.LVal, mergedArgs ?? t.objectExpression([])),
+  ]);
+
+  const statements: Babel.types.Statement[] = [argsDeclaration];
+  if (t.isBlockStatement(body)) {
+    statements.push(...body.body);
+  } else {
+    statements.push(t.returnStatement(body));
+  }
+
+  return t.arrowFunctionExpression([], t.blockStatement(statements));
+}
+
+/** Builds `() => { const args = {…}; return <Component {...args} />; }`. */
+function buildSynthesizedFunction(
+  t: typeof Babel.types,
+  componentName: string,
+  mergedArgs: Babel.types.ObjectExpression | undefined,
+): Babel.types.ArrowFunctionExpression {
+  const jsx = t.jsxElement(
+    t.jsxOpeningElement(t.jsxIdentifier(componentName), [t.jsxSpreadAttribute(t.identifier('args'))], true),
+    null,
+    [],
+    true,
+  );
+
+  const argsDeclaration = t.variableDeclaration('const', [
+    t.variableDeclarator(t.identifier('args'), mergedArgs ?? t.objectExpression([])),
+  ]);
+
+  return t.arrowFunctionExpression([], t.blockStatement([argsDeclaration, t.returnStatement(jsx)]));
+}
+
+/** Merges meta args and story args into a single object expression (story wins, keys deduped). */
+function mergeArgs(
+  t: typeof Babel.types,
+  metaArgs: Babel.types.ObjectExpression | undefined,
+  storyArgs: Babel.types.ObjectExpression | undefined,
+): Babel.types.ObjectExpression | undefined {
+  if (!metaArgs && !storyArgs) {
+    return undefined;
+  }
+
+  const byKey = new Map<string, Babel.types.ObjectExpression['properties'][number]>();
+  const order: Array<
+    { kind: 'key'; key: string } | { kind: 'raw'; node: Babel.types.ObjectExpression['properties'][number] }
+  > = [];
+
+  const add = (properties: Babel.types.ObjectExpression['properties']) => {
+    for (const property of properties) {
+      if (t.isObjectProperty(property) && !property.computed) {
+        const key = t.isIdentifier(property.key)
+          ? property.key.name
+          : t.isStringLiteral(property.key)
+          ? property.key.value
+          : undefined;
+        if (key !== undefined) {
+          if (!byKey.has(key)) {
+            order.push({ kind: 'key', key });
+          }
+          byKey.set(key, property);
+          continue;
+        }
+      }
+      order.push({ kind: 'raw', node: property });
+    }
+  };
+
+  add(metaArgs?.properties ?? []);
+  add(storyArgs?.properties ?? []);
+
+  const properties = order.map(entry => (entry.kind === 'key' ? byKey.get(entry.key)! : entry.node));
+  // Strip source locations so the synthesized object formats cleanly under
+  // `retainLines` instead of inheriting the (mismatched) lines of merged props.
+  return t.objectExpression(properties.map(property => t.cloneNode(property, true, true)));
+}
+
+/** Records `const X = {…}` / `export const X = {…}` initializers for spread resolution. */
+function collectObjectConst(
+  t: typeof Babel.types,
+  statementPath: Babel.NodePath,
+  target: Map<string, Babel.types.ObjectExpression>,
+): void {
+  const declaration = statementPath.isExportNamedDeclaration() ? statementPath.node.declaration : statementPath.node;
+  if (!declaration || !t.isVariableDeclaration(declaration)) {
+    return;
+  }
+  for (const declarator of declaration.declarations) {
+    if (t.isIdentifier(declarator.id) && declarator.init) {
+      const init = unwrapExpression(t, declarator.init);
+      if (t.isObjectExpression(init)) {
+        target.set(declarator.id.name, init);
+      }
+    }
+  }
+}
+
+/** Records local `type`/`interface`/`enum` declarations by name for type-reference resolution. */
+function collectTypeDecl(
+  t: typeof Babel.types,
+  statementPath: Babel.NodePath,
+  target: Map<string, Babel.NodePath>,
+): void {
+  if (statementPath.isTSTypeAliasDeclaration() && t.isIdentifier(statementPath.node.id)) {
+    target.set(statementPath.node.id.name, statementPath);
+  } else if (statementPath.isTSInterfaceDeclaration() && t.isIdentifier(statementPath.node.id)) {
+    target.set(statementPath.node.id.name, statementPath);
+  } else if (statementPath.isTSEnumDeclaration() && t.isIdentifier(statementPath.node.id)) {
+    target.set(statementPath.node.id.name, statementPath);
+  }
+}
+
+/**
+ * Expands `{ ...Base, … }` spread elements that reference module-level object
+ * consts (e.g. sibling CSF3 stories), so the resulting object carries the
+ * spread source's `render`/`args`. Later properties override earlier ones.
+ */
+function flattenObjectExpression(
+  t: typeof Babel.types,
+  object: Babel.types.ObjectExpression,
+  objectConstsByName: Map<string, Babel.types.ObjectExpression>,
+  seen: Set<string>,
+): Babel.types.ObjectExpression {
+  const properties: Babel.types.ObjectExpression['properties'] = [];
+
+  for (const property of object.properties) {
+    if (t.isSpreadElement(property) && t.isIdentifier(property.argument)) {
+      const name = property.argument.name;
+      const source = objectConstsByName.get(name);
+      if (source && !seen.has(name)) {
+        seen.add(name);
+        const expanded = flattenObjectExpression(t, source, objectConstsByName, seen);
+        properties.push(...expanded.properties);
+        continue;
+      }
+    }
+    properties.push(property);
+  }
+
+  return t.objectExpression(properties);
+}
+
+/**
+ * Collects the set of module-level binding paths reachable from the target story
+ * via identifier references, following declarations transitively (BFS).
+ */
+function collectReachableBindings(
+  programPath: Babel.NodePath<Babel.types.Program>,
+  targetPath: Babel.NodePath<Babel.types.ExportNamedDeclaration>,
+  typeDeclsByName: Map<string, Babel.NodePath>,
+): Set<Babel.NodePath> {
+  const needed = new Set<Babel.NodePath>();
+  const worklist: Array<Babel.NodePath> = [targetPath];
+
+  const consider = (name: string, atPath: Babel.NodePath) => {
+    const binding = atPath.scope.getBinding(name);
+    // Prefer a module-level value/import binding; fall back to a local type decl
+    // (type aliases/interfaces are not tracked by babel's scope bindings).
+    let bindingPath: Babel.NodePath | undefined;
+    if (binding && binding.scope === programPath.scope) {
+      bindingPath = binding.path;
+    } else if (!binding && typeDeclsByName.has(name)) {
+      bindingPath = typeDeclsByName.get(name);
+    }
+    if (!bindingPath || needed.has(bindingPath)) {
+      return;
+    }
+    needed.add(bindingPath);
+    worklist.push(bindingPath);
+  };
+
+  // Resolve the leftmost identifier of a (possibly qualified) type name.
+  const leftmostName = (node: Babel.types.Node | null | undefined): Babel.types.Identifier | undefined => {
+    let current = node;
+    while (current && current.type === 'TSQualifiedName') {
+      current = (current as Babel.types.TSQualifiedName).left;
+    }
+    return current && current.type === 'Identifier' ? (current as Babel.types.Identifier) : undefined;
+  };
+
+  while (worklist.length > 0) {
+    const current = worklist.pop()!;
+    current.traverse({
+      // eslint-disable-next-line @typescript-eslint/naming-convention
+      ReferencedIdentifier(idPath) {
+        consider(idPath.node.name, idPath);
+      },
+      // Follow type references (annotations, generics) so type aliases /
+      // interfaces / `import type` used by reachable code are not pruned.
+      // eslint-disable-next-line @typescript-eslint/naming-convention
+      TSTypeReference(typePath) {
+        const id = leftmostName(typePath.node.typeName);
+        if (id) {
+          consider(id.name, typePath);
+        }
+      },
+      // Follow `typeof X` type queries.
+      // eslint-disable-next-line @typescript-eslint/naming-convention
+      TSTypeQuery(queryPath) {
+        const id = leftmostName(queryPath.node.exprName as Babel.types.Node);
+        if (id) {
+          consider(id.name, queryPath);
+        }
+      },
+    });
+  }
+
+  return needed;
+}
+
+/** Prunes unused specifiers from an import declaration, removing it if empty. */
+function pruneImportDeclaration(
+  t: typeof Babel.types,
+  importPath: Babel.NodePath<Babel.types.ImportDeclaration>,
+  needed: Set<Babel.NodePath>,
+): void {
+  const specifiers = importPath.get('specifiers');
+
+  // React must remain in scope for classic-runtime JSX.
+  if (importPath.node.source.value === 'react') {
+    return;
+  }
+
+  // Side-effect import (`import './x.css'`) — always keep.
+  if (specifiers.length === 0) {
+    return;
+  }
+
+  let kept = 0;
+  for (const specifierPath of specifiers) {
+    if (needed.has(specifierPath)) {
+      kept++;
+    } else {
+      specifierPath.remove();
+    }
+  }
+
+  if (kept === 0) {
+    importPath.remove();
+  }
+}
+
+/** Whether the statement declares the given local identifier name. */
+function isDeclarationOf(t: typeof Babel.types, statementPath: Babel.NodePath, name: string): boolean {
+  if (statementPath.isVariableDeclaration()) {
+    return statementPath.node.declarations.some(d => t.isIdentifier(d.id) && d.id.name === name);
+  }
+  return false;
+}
+
+/** Whether the statement is a module-level value/type declaration. */
+function isModuleLevelDeclaration(t: typeof Babel.types, statementPath: Babel.NodePath): boolean {
+  return (
+    statementPath.isVariableDeclaration() ||
+    statementPath.isFunctionDeclaration() ||
+    statementPath.isClassDeclaration() ||
+    statementPath.isTSTypeAliasDeclaration() ||
+    statementPath.isTSInterfaceDeclaration() ||
+    statementPath.isTSEnumDeclaration()
+  );
+}
+
+/** Whether a module-level declaration is in the reachable set. */
+function isDeclarationReachable(statementPath: Babel.NodePath, needed: Set<Babel.NodePath>): boolean {
+  if (needed.has(statementPath)) {
+    return true;
+  }
+  // Variable declarations register bindings on their declarators, not the statement.
+  if (statementPath.isVariableDeclaration()) {
+    return statementPath.get('declarations').some(declaratorPath => needed.has(declaratorPath));
+  }
+  return false;
+}
+
+/** Whether the statement is a CSF2 story annotation assignment (`Story.x = …`). */
+function isStoryAnnotationAssignment(t: typeof Babel.types, statementPath: Babel.NodePath): boolean {
+  if (!statementPath.isExpressionStatement()) {
+    return false;
+  }
+  const expression = statementPath.node.expression;
+  return (
+    t.isAssignmentExpression(expression) &&
+    t.isMemberExpression(expression.left) &&
+    t.isIdentifier(expression.left.object)
+  );
+}
+
+/** Checks if the name is component-like (starts with an uppercase letter). */
+function isComponentLikeName(name: string): boolean {
+  return name.charAt(0) === name.charAt(0).toUpperCase();
+}
diff --git a/packages/react-components/babel-preset-storybook-full-source/src/types.ts b/packages/react-components/babel-preset-storybook-full-source/src/types.ts
index 683bd284e055da..94301d4deeaeae 100644
--- a/packages/react-components/babel-preset-storybook-full-source/src/types.ts
+++ b/packages/react-components/babel-preset-storybook-full-source/src/types.ts
@@ -18,6 +18,22 @@ export interface BabelPluginOptions {
   /** Map of package names to their replacement config (used by `modifyImportsPlugin`). */
   importMappings: Record<string, DependencyEntry>;
 
+  /**
+   * Controls how `fullSource` is generated when a story file contains multiple
+   * story exports (the standard Component Story Format convention).
+   *
+   * - `'file'` (default): legacy behavior — the **entire file** is attached as
+   *   `fullSource` on the **last** story export. Suited to the one-story-per-file
+   *   convention where a file maps to a single example.
+   * - `'story'`: each story export gets its **own** sliced `fullSource` containing
+   *   only the imports and helper declarations it references, plus that single
+   *   story (converted to a renderable function). Suited to files with multiple
+   *   stories per component.
+   *
+   * @default 'file'
+   */
+  storyGranularity?: 'file' | 'story';
+
   /**
    * When `true` (or a config object), the plugin will:
    *  - Preserve `*.module.css` imports (rewriting paths to `./styles/<basename>`)
diff --git a/packages/react-components/babel-preset-storybook-full-source/tsconfig.lib.json b/packages/react-components/babel-preset-storybook-full-source/tsconfig.lib.json
index 9bf4a69e7084fc..30faba083c73eb 100644
--- a/packages/react-components/babel-preset-storybook-full-source/tsconfig.lib.json
+++ b/packages/react-components/babel-preset-storybook-full-source/tsconfig.lib.json
@@ -10,6 +10,13 @@
     "types": ["static-assets", "environment", "node"],
     "module": "CommonJS"
   },
-  "exclude": ["**/*.spec.ts", "**/*.spec.tsx", "**/*.test.ts", "**/*.test.tsx", "src/index.dev.d.ts"],
+  "exclude": [
+    "**/*.spec.ts",
+    "**/*.spec.tsx",
+    "**/*.test.ts",
+    "**/*.test.tsx",
+    "src/index.dev.d.ts",
+    "**/__fixtures__/**"
+  ],
   "include": ["./src/**/*.ts", "./src/**/*.tsx"]
 }
diff --git a/packages/react-components/babel-preset-storybook-full-source/tsconfig.spec.json b/packages/react-components/babel-preset-storybook-full-source/tsconfig.spec.json
index 469fcba4d7ba75..176c1638b24c21 100644
--- a/packages/react-components/babel-preset-storybook-full-source/tsconfig.spec.json
+++ b/packages/react-components/babel-preset-storybook-full-source/tsconfig.spec.json
@@ -5,5 +5,6 @@
     "outDir": "dist",
     "types": ["jest", "node"]
   },
-  "include": ["**/*.spec.ts", "**/*.spec.tsx", "**/*.test.ts", "**/*.test.tsx", "**/*.d.ts"]
+  "include": ["**/*.spec.ts", "**/*.spec.tsx", "**/*.test.ts", "**/*.test.tsx", "**/*.d.ts"],
+  "exclude": ["**/__fixtures__/**"]
 }