diff --git a/CHANGELOG.md b/CHANGELOG.md
index 82e2029d..709178ee 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 - feat(remix): Pass `org`, `project`, `url` to `upload-sourcemaps` script (#434) 
 - fix(nextjs): Add selfhosted url in `next.config.js` (#438)
 - fix(nextjs): Create necessary directories in app router (#439)
+- fix(sourcemaps): Write package manager command instead of object to package.json (#453)
 
 Work in this release contributed by @andreysam. Thank you for your contributions!
 
diff --git a/src/sourcemaps/tools/sentry-cli.ts b/src/sourcemaps/tools/sentry-cli.ts
index 100ca690..89192ee2 100644
--- a/src/sourcemaps/tools/sentry-cli.ts
+++ b/src/sourcemaps/tools/sentry-cli.ts
@@ -1,5 +1,5 @@
 // @ts-ignore - clack is ESM and TS complains about that. It works though
-import clack from '@clack/prompts';
+import * as clack from '@clack/prompts';
 import chalk from 'chalk';
 import * as Sentry from '@sentry/node';
 import * as path from 'path';
@@ -14,7 +14,7 @@ import {
 import { SourceMapUploadToolConfigurationOptions } from './types';
 import { hasPackageInstalled, PackageDotJson } from '../../utils/package-json';
 import { traceStep } from '../../telemetry';
-import { detectPackageManger } from '../../utils/package-manager';
+import { detectPackageManger, NPM } from '../../utils/package-manager';
 
 const SENTRY_NPM_SCRIPT_NAME = 'sentry:sourcemaps';
 
@@ -194,7 +194,7 @@ async function askShouldAddToBuildCommand(): Promise<boolean> {
  *
  * @param packageDotJson The package.json which will be modified.
  */
-async function addSentryCommandToBuildCommand(
+export async function addSentryCommandToBuildCommand(
   packageDotJson: PackageDotJson,
 ): Promise<void> {
   // This usually shouldn't happen because earlier we added the
@@ -205,8 +205,7 @@ async function addSentryCommandToBuildCommand(
     (s) => s !== SENTRY_NPM_SCRIPT_NAME,
   );
 
-  const packageManager = detectPackageManger();
-  const packageManagerName = packageManager?.name ?? 'npm';
+  const packageManager = detectPackageManger() ?? NPM;
 
   // Heuristic to pre-select the build command:
   // Often, 'build' is the prod build command, so we favour it.
@@ -221,7 +220,7 @@ async function addSentryCommandToBuildCommand(
     (await abortIfCancelled(
       clack.confirm({
         message: `Is ${chalk.cyan(
-          `${packageManagerName} run ${buildCommand}`,
+          `${packageManager.runScriptCommand} ${buildCommand}`,
         )} your production build command?`,
       }),
     ));
@@ -229,7 +228,7 @@ async function addSentryCommandToBuildCommand(
   if (allNpmScripts.length && (!buildCommand || !isProdBuildCommand)) {
     buildCommand = await abortIfCancelled(
       clack.select({
-        message: `Which ${packageManagerName} command in your ${chalk.cyan(
+        message: `Which ${packageManager.name} command in your ${chalk.cyan(
           'package.json',
         )} builds your application for production?`,
         options: allNpmScripts
@@ -252,10 +251,18 @@ Please add it manually to your prod build command.`,
     return;
   }
 
+  const oldCommand = packageDotJson.scripts[buildCommand];
+  if (!oldCommand) {
+    // very unlikely to happen but nevertheless
+    clack.log.warn(
+      `\`${buildCommand}\` doesn't seem to be part of your package.json scripts`,
+    );
+    return;
+  }
+
   packageDotJson.scripts[
     buildCommand
-    // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
-  ] = `${packageDotJson.scripts[buildCommand]} && ${packageManager} run ${SENTRY_NPM_SCRIPT_NAME}`;
+  ] = `${oldCommand} && ${packageManager.runScriptCommand} ${SENTRY_NPM_SCRIPT_NAME}`;
 
   await fs.promises.writeFile(
     path.join(process.cwd(), 'package.json'),
diff --git a/src/utils/package-manager.ts b/src/utils/package-manager.ts
index 5e19457f..ff793a4b 100644
--- a/src/utils/package-manager.ts
+++ b/src/utils/package-manager.ts
@@ -10,38 +10,44 @@ export interface PackageManager {
   lockFile: string;
   installCommand: string;
   buildCommand: string;
+  /* The command that the package manager uses to run a script from package.json */
+  runScriptCommand: string;
 }
 
-const bun: PackageManager = {
+export const BUN: PackageManager = {
   name: 'bun',
   label: 'Bun',
   lockFile: 'bun.lockb',
   installCommand: 'bun add',
-  buildCommand: 'bun build',
+  buildCommand: 'bun run build',
+  runScriptCommand: 'bun run',
 };
-const yarn: PackageManager = {
+export const YARN: PackageManager = {
   name: 'yarn',
   label: 'Yarn',
   lockFile: 'yarn.lock',
   installCommand: 'yarn add',
   buildCommand: 'yarn build',
+  runScriptCommand: 'yarn',
 };
-const pnpm: PackageManager = {
+export const PNPM: PackageManager = {
   name: 'pnpm',
   label: 'PNPM',
   lockFile: 'pnpm-lock.yaml',
   installCommand: 'pnpm add',
   buildCommand: 'pnpm build',
+  runScriptCommand: 'pnpm',
 };
-const npm: PackageManager = {
+export const NPM: PackageManager = {
   name: 'npm',
   label: 'NPM',
   lockFile: 'package-lock.json',
   installCommand: 'npm add',
   buildCommand: 'npm run build',
+  runScriptCommand: 'npm run',
 };
 
-export const packageManagers = [bun, yarn, pnpm, npm];
+export const packageManagers = [BUN, YARN, PNPM, NPM];
 
 export function detectPackageManger(): PackageManager | null {
   for (const packageManager of packageManagers) {
diff --git a/test/sourcemaps/tools/sentry-cli.test.ts b/test/sourcemaps/tools/sentry-cli.test.ts
new file mode 100644
index 00000000..30deb5d1
--- /dev/null
+++ b/test/sourcemaps/tools/sentry-cli.test.ts
@@ -0,0 +1,51 @@
+import * as fs from 'fs';
+
+import { addSentryCommandToBuildCommand } from '../../../src/sourcemaps/tools/sentry-cli';
+
+import * as packageManagerHelpers from '../../../src/utils/package-manager';
+
+const writeFileSpy = jest
+  .spyOn(fs.promises, 'writeFile')
+  .mockImplementation(() => Promise.resolve());
+
+jest.mock('@clack/prompts', () => {
+  return {
+    log: {
+      info: jest.fn(),
+      success: jest.fn(),
+    },
+    confirm: jest.fn().mockResolvedValue(true),
+    isCancel: jest.fn().mockReturnValue(false),
+  };
+});
+
+describe('addSentryCommandToBuildCommand', () => {
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+  it.each([
+    [
+      packageManagerHelpers.NPM,
+      packageManagerHelpers.PNPM,
+      packageManagerHelpers.YARN,
+      packageManagerHelpers.BUN,
+    ],
+  ])('adds the cli command to the script command (%s)', async (_, pacMan) => {
+    jest
+      .spyOn(packageManagerHelpers, 'detectPackageManger')
+      .mockReturnValue(pacMan);
+    const packageJson = {
+      scripts: {
+        build: 'tsc',
+      },
+      version: '1.0.0',
+    };
+    await addSentryCommandToBuildCommand(packageJson);
+    expect(writeFileSpy).toHaveBeenCalledWith(
+      expect.stringContaining('package.json'),
+      expect.stringContaining(
+        `tsc && ${pacMan.runScriptCommand} sentry:sourcemaps`,
+      ),
+    );
+  });
+});