diff --git a/packages/desktop/electron.vite.config.ts b/packages/desktop/electron.vite.config.ts
index 6cbba544cdc..1e9dcf6e090 100644
--- a/packages/desktop/electron.vite.config.ts
+++ b/packages/desktop/electron.vite.config.ts
@@ -60,20 +60,11 @@ export default defineConfig(async ({ command }) => {
         minify: command === "build",
         rolldownOptions: {
           input: { index: "src/main/index.ts" },
-          // Keep this identical to electron-vite's Node 20.11+ shim. Its regex insertion can
-          // corrupt bundled TypeScript, while an output banner places the shim safely.
           output: {
             format: "es",
             // DesktopPaths resolves resources from the main output directory,
             // including when the lazy desktop entry shares it with other chunks.
             chunkFileNames: "[name]-[hash].js",
-            banner: `
-// -- CommonJS Shims --
-import __cjs_mod__ from 'node:module';
-const __filename = import.meta.filename;
-const __dirname = import.meta.dirname;
-const require = __cjs_mod__.createRequire(import.meta.url);
-`,
           },
         },
         externalizeDeps: {
@@ -92,6 +83,17 @@ const require = __cjs_mod__.createRequire(import.meta.url);
             return undefined
           },
         },
+        {
+          // Rolldown emits its own scoped createRequire runtime for CommonJS dependencies.
+          // electron-vite's post-bundle regex shim injects a top-level `const require` that collides
+          // with bundled ESM modules declaring their own `require` (such as @effect/platform-node).
+          name: "opencode:disable-esm-shim",
+          configResolved(config) {
+            const shim = config.plugins.find((plugin) => plugin.name === "vite:esm-shim")
+
+            if (shim) delete shim.renderChunk
+          },
+        },
       ],
     },
     preload: {
diff --git a/packages/desktop/script/build.ts b/packages/desktop/script/build.ts
index e46e7580e10..6d55837c170 100644
--- a/packages/desktop/script/build.ts
+++ b/packages/desktop/script/build.ts
@@ -3,6 +3,7 @@ import { $ } from "bun"
 import { exists } from "node:fs/promises"
 import path from "node:path"
 import { copyBuiltCliToResources, downloadCliToResources, getCurrentCli, resolveChannel } from "./utils"
+import { verifyBundles } from "./verify-bundles"
 
 // Prepares resources/ (icons, metainfo, the bundled CLI) for OPENCODE_CHANNEL and builds the app into out/.
 // The CLI comes from ../cli/dist when it holds the target; otherwise dev downloads the published dev CLI,
@@ -29,3 +30,5 @@ if (built) await copyBuiltCliToResources(cli)
 if (!built) await downloadCliToResources(channel === "beta" ? "beta" : undefined)
 
 await $`bunx electron-vite build`
+
+await verifyBundles(path.join(dir, "out"))
diff --git a/packages/desktop/script/verify-bundles.ts b/packages/desktop/script/verify-bundles.ts
new file mode 100644
index 00000000000..a545ee70291
--- /dev/null
+++ b/packages/desktop/script/verify-bundles.ts
@@ -0,0 +1,51 @@
+import path from "node:path"
+import { Script, SourceTextModule } from "node:vm"
+
+const targets = ["main", "preload"] as const
+
+// Parses every built main and preload bundle without executing it, catching syntax and early
+// redeclaration errors even in chunks that the app loads lazily at runtime.
+export async function verifyBundles(outDir: string) {
+  const glob = new Bun.Glob("**/*.{js,cjs,mjs}")
+  const failures: string[] = []
+
+  for (const target of targets) {
+    const dir = path.join(outDir, target)
+    const files = await Array.fromAsync(glob.scan({ cwd: dir, onlyFiles: true })).catch(() => [])
+
+    if (files.length === 0) throw new Error(`Expected built chunks in ${dir}, found none`)
+
+    const errors = await Promise.all(
+      files.sort().map(async (file) => {
+        const label = `${target}/${file.replaceAll("\\", "/")}`
+        const error = parseError(await Bun.file(path.join(dir, file)).text(), label)
+
+        return error ? `${label}: ${error}` : undefined
+      }),
+    )
+
+    failures.push(...errors.filter((item): item is string => item !== undefined))
+  }
+
+  if (failures.length > 0) throw new Error(`Desktop bundle syntax check failed:\n${failures.join("\n")}`)
+}
+
+function parseError(code: string, identifier: string) {
+  const source = code.replace(/^#!.*\r?\n/, "\n")
+
+  try {
+    if (identifier.endsWith(".cjs")) {
+      new Script(`(function (exports, require, module, __filename, __dirname) { ${source}\n})`, {
+        filename: identifier,
+      })
+
+      return undefined
+    }
+
+    new SourceTextModule(source, { identifier })
+
+    return undefined
+  } catch (error) {
+    return error instanceof Error ? error.message : String(error)
+  }
+}