diff --git a/napi/angular-compiler/test/dts.test.ts b/napi/angular-compiler/test/dts.test.ts
index 3337a997a..3834a9b9c 100644
--- a/napi/angular-compiler/test/dts.test.ts
+++ b/napi/angular-compiler/test/dts.test.ts
@@ -526,6 +526,28 @@ describe('angular() dts plugin (#104)', () => {
     expect(out).toContain('static ɵcmp: i0.ɵɵComponentDeclaration<LibButtonComponent')
   })
 
+  it('augments .d.ts chunks in partial mode (rolldown-plugin-dts)', async () => {
+    const { transform, dts } = getPlugins('partial')
+    await runTransform(transform)
+
+    const js = 'export class LibButtonComponent {}\n'
+    const bundle = {
+      'index.d.mts': {
+        type: 'chunk' as const,
+        fileName: 'index.d.mts',
+        code: 'export declare class LibButtonComponent {\n}\n',
+      },
+      'index.mjs': { type: 'chunk' as const, fileName: 'index.mjs', code: js },
+    }
+    await runGenerateBundle(dts, bundle)
+
+    const out = bundle['index.d.mts'].code
+    expect(out).toContain('import * as i0 from "@angular/core";')
+    expect(out).toContain('static ɵfac: i0.ɵɵFactoryDeclaration<LibButtonComponent')
+    expect(out).toContain('static ɵcmp: i0.ɵɵComponentDeclaration<LibButtonComponent')
+    expect(bundle['index.mjs'].code).toBe(js)
+  })
+
   it('does not touch declarations in full (app) mode', async () => {
     const { transform, dts } = getPlugins('full')
     await runTransform(transform)
diff --git a/napi/angular-compiler/vite-plugin/index.ts b/napi/angular-compiler/vite-plugin/index.ts
index 0b4230fef..2a0b660e4 100644
--- a/napi/angular-compiler/vite-plugin/index.ts
+++ b/napi/angular-compiler/vite-plugin/index.ts
@@ -1777,17 +1777,25 @@ export function angular(options: PluginOptions = {}): Plugin[] {
         const declarations = Array.from(byClassName.values())
 
         for (const file of Object.values(bundle)) {
-          if (file.type !== 'asset') continue
           if (!/\.d\.[cm]?ts$/.test(file.fileName)) continue
 
-          const source =
-            typeof file.source === 'string'
-              ? file.source
-              : Buffer.from(file.source).toString('utf-8')
-
-          const augmented = injectDtsDeclarations(source, declarations)
-          if (augmented !== source) {
-            file.source = augmented
+          // rolldown-plugin-dts (and so tsdown) emits declarations as
+          // chunks; other generators emit them as assets.
+          if (file.type === 'chunk') {
+            const augmented = injectDtsDeclarations(file.code, declarations)
+            if (augmented !== file.code) {
+              file.code = augmented
+            }
+          } else if (file.type === 'asset') {
+            const source =
+              typeof file.source === 'string'
+                ? file.source
+                : Buffer.from(file.source).toString('utf-8')
+
+            const augmented = injectDtsDeclarations(source, declarations)
+            if (augmented !== source) {
+              file.source = augmented
+            }
           }
         }
       },