diff --git a/napi/angular-compiler/README.md b/napi/angular-compiler/README.md
index 1e4d74d7c..bf36c0083 100644
--- a/napi/angular-compiler/README.md
+++ b/napi/angular-compiler/README.md
@@ -286,7 +286,7 @@ type-checking against your library.
 ```typescript
 // vite.config.ts — Angular library build
 import { angular } from '@oxc-angular/vite'
-import dts from 'rolldown-plugin-dts' // or vite-plugin-dts / tsdown
+import { dts } from 'rolldown-plugin-dts'
 
 export default defineConfig({
   plugins: [angular({ compilationMode: 'partial' }), dts()],
@@ -295,11 +295,16 @@ export default defineConfig({
 ```
 
 The plugin does **not** generate the base `.d.ts` itself — a declaration
-generator (`rolldown-plugin-dts`, `vite-plugin-dts`, `tsdown`, or `tsc`) must
-produce them. The Angular members are then spliced into those files during
-`generateBundle`. The injected members reference `i0` (the `@angular/core`
-namespace), and the plugin adds `import * as i0 from "@angular/core";` to any
-`.d.ts` it augments.
+generator must produce them in the bundle, as `rolldown-plugin-dts` and
+`tsdown` (`dts: true`) do. The Angular members are then spliced into those
+files during `generateBundle`. The injected members reference `i0` (the
+`@angular/core` namespace), and the plugin adds
+`import * as i0 from "@angular/core";` to any `.d.ts` it augments.
+
+Declarations written outside the bundle are not augmented: `vite-plugin-dts`
+and `tsc` write their files themselves, and tsdown builds the `.d.cts` of a
+`cjs` format in a separate pass without user plugins. Use `format: 'esm'` with
+tsdown.
 
 ## Vite Plugin Architecture
 
diff --git a/napi/angular-compiler/test/dts.test.ts b/napi/angular-compiler/test/dts.test.ts
index 3337a997a..762fa369b 100644
--- a/napi/angular-compiler/test/dts.test.ts
+++ b/napi/angular-compiler/test/dts.test.ts
@@ -526,6 +526,48 @@ 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('augments shared .d.ts chunks that export the class under another name', async () => {
+    const { transform, dts } = getPlugins('partial')
+    await runTransform(transform)
+
+    // The shape rolldown-plugin-dts gives a chunk shared by several entries.
+    const bundle = {
+      'shared-abc.d.mts': {
+        type: 'chunk' as const,
+        fileName: 'shared-abc.d.mts',
+        code: 'declare class LibButtonComponent {\n}\nexport { LibButtonComponent as t };\n',
+      },
+    }
+    await runGenerateBundle(dts, bundle)
+
+    const out = bundle['shared-abc.d.mts'].code
+    expect(out).toContain('import * as i0 from "@angular/core";')
+    expect(out).toContain('static ɵcmp: i0.ɵɵComponentDeclaration<LibButtonComponent')
+    expect(out).toContain('export { LibButtonComponent as t };')
+  })
+
   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..c49d0e203 100644
--- a/napi/angular-compiler/vite-plugin/index.ts
+++ b/napi/angular-compiler/vite-plugin/index.ts
@@ -1777,16 +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')
+          // rolldown-plugin-dts (and so tsdown) emits declarations as
+          // chunks; generators that call `emitFile` emit them as assets.
+          let source: string
+          if (file.type === 'chunk') {
+            source = file.code
+          } else {
+            source =
+              typeof file.source === 'string'
+                ? file.source
+                : Buffer.from(file.source).toString('utf-8')
+          }
 
           const augmented = injectDtsDeclarations(source, declarations)
-          if (augmented !== source) {
+          if (augmented === source) continue
+          if (file.type === 'chunk') {
+            file.code = augmented
+          } else {
             file.source = augmented
           }
         }