diff --git a/src/utils/atproto-adapter.js b/src/utils/atproto-adapter.js
index baf1b5c9..0bb8f698 100644
--- a/src/utils/atproto-adapter.js
+++ b/src/utils/atproto-adapter.js
@@ -3,6 +3,10 @@ import { getPdsEndpoint } from '@atproto/common-web';
 
 import { encodeAtprotoID } from './atproto-route';
 import { createAtprotoOAuthAgent } from './atproto-oauth';
+import {
+  createAtprotoExternalEmbed,
+  getFirstPostURL,
+} from './atproto-unfurl';
 import {
   BSKY_PDS,
   resolveAtprotoLoginService,
@@ -1801,6 +1805,17 @@ export function createAtprotoClient({
               }
             }
           }
+          if (!record.embed) {
+            const externalEmbed = await createAtprotoExternalEmbed(
+              agent,
+              params.card_url ||
+                params.cardUrl ||
+                params.external_url ||
+                params.externalUrl ||
+                getFirstPostURL(rt.text),
+            );
+            if (externalEmbed) record.embed = externalEmbed;
+          }
           const res = await agent.post(record);
           const id = encodeAtprotoID(res.uri);
           for (let i = 0; i < 10; i++) {
diff --git a/src/utils/atproto-unfurl.js b/src/utils/atproto-unfurl.js
new file mode 100644
index 00000000..3596922d
--- /dev/null
+++ b/src/utils/atproto-unfurl.js
@@ -0,0 +1,63 @@
+export const BSKY_LINK_META_PROXY = 'https://cardyb.bsky.app/v1/extract?url=';
+
+const HTTP_URL_RE = /https?:\/\/[^\s<>"']+/i;
+
+export function getFirstPostURL(text = '') {
+  const match = HTTP_URL_RE.exec(text);
+  return match?.[0]?.replace(/[),.;!?]+$/, '') || null;
+}
+
+function getAssociatedRecord(value) {
+  if (!value || typeof value !== 'object') return undefined;
+  return value;
+}
+
+export async function createAtprotoExternalEmbed(
+  agent,
+  uri,
+  { fetcher = fetch } = {},
+) {
+  if (!uri) return null;
+  let metadata;
+  try {
+    const res = await fetcher(`${BSKY_LINK_META_PROXY}${encodeURIComponent(uri)}`);
+    if (!res.ok) return null;
+    metadata = await res.json();
+  } catch (e) {
+    console.error('Failed to fetch Bluesky link metadata', e);
+    return null;
+  }
+  if (metadata?.error) return null;
+
+  const external = {
+    uri: metadata.url || uri,
+    title: metadata.title || '',
+    description: metadata.description || '',
+  };
+  const associatedRecord = getAssociatedRecord(
+    metadata.associatedRecord || metadata.associated_record,
+  );
+  if (associatedRecord) external.associatedRecord = associatedRecord;
+
+  if (metadata.image) {
+    try {
+      const imageRes = await fetcher(metadata.image);
+      if (imageRes.ok) {
+        const imageBlob = await imageRes.blob();
+        if (imageBlob.size > 0) {
+          const uploadRes = await agent.uploadBlob(imageBlob, {
+            encoding: imageBlob.type || 'image/jpeg',
+          });
+          if (uploadRes.data?.blob) external.thumb = uploadRes.data.blob;
+        }
+      }
+    } catch (e) {
+      console.error('Failed to upload Bluesky link thumbnail', e);
+    }
+  }
+
+  return {
+    $type: 'app.bsky.embed.external',
+    external,
+  };
+}
diff --git a/tests/atproto-unfurl.spec.js b/tests/atproto-unfurl.spec.js
new file mode 100644
index 00000000..ca509f31
--- /dev/null
+++ b/tests/atproto-unfurl.spec.js
@@ -0,0 +1,79 @@
+import { expect, test } from '@playwright/test';
+
+import {
+  createAtprotoExternalEmbed,
+  getFirstPostURL,
+} from '../src/utils/atproto-unfurl.js';
+
+test.describe('ATProto compose helpers', () => {
+  test('builds external embeds from cardyb metadata', async () => {
+    const uploads = [];
+    const agent = {
+      uploadBlob: async (blob, options) => {
+        uploads.push({ size: blob.size, encoding: options.encoding });
+        return {
+          data: {
+            blob: {
+              $type: 'blob',
+              ref: { $link: 'bafkreicardthumb' },
+              mimeType: options.encoding,
+              size: blob.size,
+            },
+          },
+        };
+      },
+    };
+    const fetcher = async (url) => {
+      const urlString = String(url);
+      if (urlString.startsWith('https://cardyb.bsky.app/v1/extract?url=')) {
+        return Response.json({
+          error: '',
+          url: 'https://docs.bsky.app/',
+          title: 'Bluesky Documentation',
+          description: 'Explore guides and tutorials.',
+          image: 'https://image.test/card.png',
+          associated_record: {
+            uri: 'at://did:plc:test/app.bsky.feed.post/abc',
+            cid: 'bafyreitest',
+          },
+        });
+      }
+      if (urlString === 'https://image.test/card.png') {
+        return new Response(new Blob(['png'], { type: 'image/png' }));
+      }
+      return new Response('', { status: 404 });
+    };
+
+    const embed = await createAtprotoExternalEmbed(
+      agent,
+      'https://docs.bsky.app',
+      { fetcher },
+    );
+
+    expect(getFirstPostURL('read https://docs.bsky.app please')).toBe(
+      'https://docs.bsky.app',
+    );
+    expect(getFirstPostURL('read https://docs.bsky.app.')).toBe(
+      'https://docs.bsky.app',
+    );
+    expect(uploads).toEqual([{ size: 3, encoding: 'image/png' }]);
+    expect(embed).toEqual({
+      $type: 'app.bsky.embed.external',
+      external: {
+        uri: 'https://docs.bsky.app/',
+        title: 'Bluesky Documentation',
+        description: 'Explore guides and tutorials.',
+        associatedRecord: {
+          uri: 'at://did:plc:test/app.bsky.feed.post/abc',
+          cid: 'bafyreitest',
+        },
+        thumb: {
+          $type: 'blob',
+          ref: { $link: 'bafkreicardthumb' },
+          mimeType: 'image/png',
+          size: 3,
+        },
+      },
+    });
+  });
+});