diff --git a/__tests__/buildx/imagetools.test.ts b/__tests__/buildx/imagetools.test.ts
index 8dbc1a4d..8c1381ff 100644
--- a/__tests__/buildx/imagetools.test.ts
+++ b/__tests__/buildx/imagetools.test.ts
@@ -48,6 +48,35 @@ beforeEach(() => {
   fs.mkdirSync(tmpDir, {recursive: true});
 });
 
+describe('toIndexAnnotation', () => {
+  it.each([
+    ['org.opencontainers.image.title=example', 'index:org.opencontainers.image.title=example'],
+    ['manifest:key=value', 'index:key=value'],
+    ['index:key=value', 'index:key=value'],
+    ['manifest-descriptor:key=value', 'index:key=value'],
+    ['index-descriptor:key=value', 'index:key=value'],
+    ['manifest,index:key=value', 'index:key=value'],
+    ['manifest[linux/amd64]:key=value', 'index:key=value'],
+    ['manifest-descriptor[linux/arm/v7]:key=value', 'index:key=value'],
+    ['manifest[linux/amd64],manifest[linux/arm64]:key=value', 'index:key=value'],
+    ['index[linux/amd64]:key=value', 'index:key=value'],
+    ['key=https://example.com/path?a=b=c', 'index:key=https://example.com/path?a=b=c'],
+    ['manifest:key=manifest:other=value', 'index:key=manifest:other=value'],
+    ['custom:key=value', 'index:custom:key=value'],
+    ['manifest:custom:key=value', 'index:custom:key=value'],
+    ['key=', 'index:key='],
+    ['manifest:key=', 'index:key='],
+    ['key', 'index:key'],
+    ['manifest:key', 'index:key'],
+    ['manifest:key=  value  ', 'index:key=  value  '],
+    ['', 'index:'],
+    ['unknown,manifest:key=value', 'index:key=value'],
+    ['unknown,custom:key=value', 'index:unknown,custom:key=value']
+  ])('converts %j to %j', (input, expected) => {
+    expect(ImageTools.toIndexAnnotation(input)).toBe(expected);
+  });
+});
+
 describe('inspectManifest', () => {
   // prettier-ignore
   it.each([
diff --git a/src/buildx/imagetools.ts b/src/buildx/imagetools.ts
index c3656f1b..a20f43a7 100644
--- a/src/buildx/imagetools.ts
+++ b/src/buildx/imagetools.ts
@@ -112,6 +112,26 @@ export class ImageTools {
     return (await this.attestationDescriptors(opts)).map(attestation => attestation.digest);
   }
 
+  // Retargets an annotation to the index, dropping existing scopes and platform selectors
+  public static toIndexAnnotation(annotation: string): string {
+    const keyEnd = annotation.indexOf('=');
+    const rawKey = keyEnd === -1 ? annotation : annotation.substring(0, keyEnd);
+    const rawValue = keyEnd === -1 ? '' : annotation.substring(keyEnd);
+    const typeSeparator = rawKey.indexOf(':');
+    if (typeSeparator !== -1) {
+      const typeExpr = rawKey.substring(0, typeSeparator);
+      const key = rawKey.substring(typeSeparator + 1);
+      const hasKnownType = typeExpr
+        .split(',')
+        .map(type => type.replace(/\[.*\]$/, ''))
+        .some(type => ['manifest', 'index', 'manifest-descriptor', 'index-descriptor'].includes(type));
+      if (hasKnownType) {
+        return `index:${key}${rawValue}`;
+      }
+    }
+    return `index:${annotation}`;
+  }
+
   public async create(opts: CreateOpts): Promise<CreateResult | undefined> {
     const args: Array<string> = [];