From ebd463070223fe497aa821fd7bdb51466e49c783 Mon Sep 17 00:00:00 2001
From: Gabriel Dugny <gabriel.dugny@believe.com>
Date: Thu, 29 Jan 2026 09:03:19 +0100
Subject: [PATCH 1/6] chore: replace legacy package.json workspaces.packages by
 workspaces

Signed-off-by: Gabriel Dugny <gabriel.dugny@believe.com>
---
 .changeset/slow-items-pull.md                  | 18 ++++++++++++++++++
 docs/contribute/project-structure.md           | 10 ++++------
 package.json                                   | 10 ++++------
 .../templates/default-app/package.json.hbs     | 10 ++++------
 .../templates/next-app/package.json.hbs        | 10 ++++------
 5 files changed, 34 insertions(+), 24 deletions(-)
 create mode 100644 .changeset/slow-items-pull.md

diff --git a/.changeset/slow-items-pull.md b/.changeset/slow-items-pull.md
new file mode 100644
index 0000000000..50f4897fa5
--- /dev/null
+++ b/.changeset/slow-items-pull.md
@@ -0,0 +1,18 @@
+---
+'@backstage/create-app': patch
+---
+
+Replace `package.json` deprecated `workspaces.packages` by `workspaces`
+
+This change is **not** required, but you can edit your main `package.json`, to fit the more modern & more common pattern:
+
+```diff
+-  "workspaces": {
+-    "packages": [
+   "workspaces": [
+     "packages/*",
+     "plugins/*"
+-     ]
+-   },
+  ],
+```
diff --git a/docs/contribute/project-structure.md b/docs/contribute/project-structure.md
index f58afedee8..372fb79844 100644
--- a/docs/contribute/project-structure.md
+++ b/docs/contribute/project-structure.md
@@ -55,12 +55,10 @@ defined in
 [`package.json`](https://github.com/backstage/backstage/blob/master/package.json):
 
 ```json
- "workspaces": {
-    "packages": [
-      "packages/*",
-      "plugins/*"
-    ]
-  },
+  "workspaces": [
+    "packages/*",
+    "plugins/*"
+  ],
 ```
 
 Let's look at them individually.
diff --git a/package.json b/package.json
index a0a530adb8..5a63fbc2db 100644
--- a/package.json
+++ b/package.json
@@ -16,12 +16,10 @@
     "type": "git",
     "url": "https://github.com/backstage/backstage"
   },
-  "workspaces": {
-    "packages": [
-      "packages/*",
-      "plugins/*"
-    ]
-  },
+  "workspaces": [
+    "packages/*",
+    "plugins/*"
+  ],
   "scripts": {
     "build-storybook": "storybook build --output-dir dist-storybook",
     "build-storybook:chromatic": "STORYBOOK_STORY_SET=chromatic storybook build --stats-json --output-dir dist-storybook",
diff --git a/packages/create-app/templates/default-app/package.json.hbs b/packages/create-app/templates/default-app/package.json.hbs
index 4e723ea078..229ed5ffa0 100644
--- a/packages/create-app/templates/default-app/package.json.hbs
+++ b/packages/create-app/templates/default-app/package.json.hbs
@@ -22,12 +22,10 @@
     "prettier:check": "prettier --check .",
     "new": "backstage-cli new"
   },
-  "workspaces": {
-    "packages": [
-      "packages/*",
-      "plugins/*"
-    ]
-  },
+  "workspaces": [
+    "packages/*",
+    "plugins/*"
+  ],
   "devDependencies": {
     "@backstage/cli": "^{{version '@backstage/cli'}}",
     "@backstage/e2e-test-utils": "^{{version '@backstage/e2e-test-utils'}}",
diff --git a/packages/create-app/templates/next-app/package.json.hbs b/packages/create-app/templates/next-app/package.json.hbs
index 80ff4a9a06..27d5880c11 100644
--- a/packages/create-app/templates/next-app/package.json.hbs
+++ b/packages/create-app/templates/next-app/package.json.hbs
@@ -44,12 +44,10 @@
       }
     }
   },
-  "workspaces": {
-    "packages": [
-      "packages/*",
-      "plugins/*"
-    ]
-  },
+  "workspaces": [
+    "packages/*",
+    "plugins/*"
+  ],
   "devDependencies": {
     "@backstage/cli": "^{{version '@backstage/cli'}}",
     "@backstage/e2e-test-utils": "^{{version '@backstage/e2e-test-utils'}}",

From a9d23c4a322717b14648dfbc3c38d206a0f1cfd4 Mon Sep 17 00:00:00 2001
From: Gabriel Dugny <gabriel.dugny@believe.com>
Date: Thu, 29 Jan 2026 10:24:31 +0100
Subject: [PATCH 2/6] fix: Support workspaces in CLIs

Signed-off-by: Gabriel Dugny <gabriel.dugny@believe.com>
---
 .changeset/slick-dogs-pay.md                  |  8 +++
 packages/cli-common/report.api.md             |  3 ++
 packages/cli-common/src/index.ts              |  2 +-
 packages/cli-common/src/paths.ts              | 21 +++++++-
 packages/cli-node/src/monorepo/isMonoRepo.ts  |  3 +-
 .../src/pacman/PackageManager.test.ts         | 12 ++++-
 .../cli-node/src/pacman/PackageManager.ts     |  4 +-
 .../cli-node/src/pacman/yarn/Yarn.test.ts     | 11 +++-
 packages/cli-node/src/pacman/yarn/Yarn.ts     |  3 +-
 packages/cli/config/jest.js                   |  6 +--
 .../cli/src/lib/versioning/packages.test.ts   |  4 +-
 .../migrate/commands/versions/bump.test.ts    | 52 +++++--------------
 .../migrate/commands/versions/migrate.test.ts | 12 ++---
 13 files changed, 79 insertions(+), 62 deletions(-)
 create mode 100644 .changeset/slick-dogs-pay.md

diff --git a/.changeset/slick-dogs-pay.md b/.changeset/slick-dogs-pay.md
new file mode 100644
index 0000000000..f75382aa02
--- /dev/null
+++ b/.changeset/slick-dogs-pay.md
@@ -0,0 +1,8 @@
+---
+'@backstage/cli-common': patch
+'@backstage/create-app': patch
+'@backstage/cli-node': patch
+'@backstage/cli': patch
+---
+
+Properly support `package.json` `workspaces` field
diff --git a/packages/cli-common/report.api.md b/packages/cli-common/report.api.md
index 96475c6bd1..ec146f78c4 100644
--- a/packages/cli-common/report.api.md
+++ b/packages/cli-common/report.api.md
@@ -23,6 +23,9 @@ export class ExitCodeError extends CustomErrorBase {
 // @public
 export function findPaths(searchDir: string): Paths;
 
+// @public
+export function getWorkspacesPatterns(pkgJson: any): string[];
+
 // @public
 export function isChildPath(base: string, path: string): boolean;
 
diff --git a/packages/cli-common/src/index.ts b/packages/cli-common/src/index.ts
index d11601b044..146af314cd 100644
--- a/packages/cli-common/src/index.ts
+++ b/packages/cli-common/src/index.ts
@@ -20,7 +20,7 @@
  * @packageDocumentation
  */
 
-export { findPaths, BACKSTAGE_JSON } from './paths';
+export { findPaths, getWorkspacesPatterns, BACKSTAGE_JSON } from './paths';
 export { isChildPath } from './isChildPath';
 export type { Paths, ResolveFunc } from './paths';
 export { bootstrapEnvProxyAgents } from './proxyBootstrap';
diff --git a/packages/cli-common/src/paths.ts b/packages/cli-common/src/paths.ts
index 5da2d596a4..557af7ccca 100644
--- a/packages/cli-common/src/paths.ts
+++ b/packages/cli-common/src/paths.ts
@@ -107,6 +107,25 @@ export function findOwnRootDir(ownDir: string) {
   return resolvePath(ownDir, '../..');
 }
 
+/**
+ * Gets the workspaces pattern from a package.json object.
+ * @param pkgJson - The package.json object to get the workspaces pattern from.
+ * @returns The workspaces patterns (glob not resolved).
+ * @public
+ */
+export function getWorkspacesPatterns(pkgJson: any): string[] {
+  if (Array.isArray(pkgJson.workspaces)) {
+    return pkgJson.workspaces;
+  } else if (
+    typeof pkgJson.workspaces === 'object' &&
+    pkgJson.workspaces !== null &&
+    Array.isArray(pkgJson.workspaces.packages)
+  ) {
+    return pkgJson.workspaces.packages;
+  }
+  return [];
+}
+
 /**
  * Find paths related to a package and its execution context.
  *
@@ -141,7 +160,7 @@ export function findPaths(searchDir: string): Paths {
           try {
             const content = fs.readFileSync(path, 'utf8');
             const data = JSON.parse(content);
-            return Boolean(data.workspaces);
+            return getWorkspacesPatterns(data).length > 0;
           } catch (error) {
             throw new Error(
               `Failed to parse package.json file while searching for root, ${error}`,
diff --git a/packages/cli-node/src/monorepo/isMonoRepo.ts b/packages/cli-node/src/monorepo/isMonoRepo.ts
index da78c8dd53..9cb19ea62f 100644
--- a/packages/cli-node/src/monorepo/isMonoRepo.ts
+++ b/packages/cli-node/src/monorepo/isMonoRepo.ts
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import { getWorkspacesPatterns } from '@backstage/cli-common';
 import { paths } from '../paths';
 import fs from 'fs-extra';
 
@@ -26,7 +27,7 @@ export async function isMonoRepo(): Promise<boolean> {
   const rootPackageJsonPath = paths.resolveTargetRoot('package.json');
   try {
     const pkg = await fs.readJson(rootPackageJsonPath);
-    return Boolean(pkg?.workspaces?.packages);
+    return getWorkspacesPatterns(pkg).length > 0;
   } catch (error) {
     return false;
   }
diff --git a/packages/cli-node/src/pacman/PackageManager.test.ts b/packages/cli-node/src/pacman/PackageManager.test.ts
index dd35e74902..fd7ace5bcb 100644
--- a/packages/cli-node/src/pacman/PackageManager.test.ts
+++ b/packages/cli-node/src/pacman/PackageManager.test.ts
@@ -43,7 +43,7 @@ describe('PackageManager', () => {
         expect(mockYarnCreate).toHaveBeenCalled();
       });
 
-      it('should detect via root package.json workspaces', async () => {
+      it('should detect via root package.json workspaces with legacy workspaces.packages field', async () => {
         mockDir.setContent({
           'package.json': JSON.stringify({
             name: 'foo',
@@ -55,6 +55,16 @@ describe('PackageManager', () => {
         await detectPackageManager();
         expect(mockYarnCreate).toHaveBeenCalled();
       });
+      it('should detect via root package.json workspaces', async () => {
+        mockDir.setContent({
+          'package.json': JSON.stringify({
+            name: 'foo',
+            workspaces: [],
+          }),
+        });
+        await detectPackageManager();
+        expect(mockYarnCreate).toHaveBeenCalled();
+      });
 
       it('should detect via root package.json packageManager', async () => {
         mockDir.setContent({
diff --git a/packages/cli-node/src/pacman/PackageManager.ts b/packages/cli-node/src/pacman/PackageManager.ts
index 44c0849705..5693acce06 100644
--- a/packages/cli-node/src/pacman/PackageManager.ts
+++ b/packages/cli-node/src/pacman/PackageManager.ts
@@ -17,7 +17,7 @@
 import { Yarn } from './yarn';
 import { Lockfile } from './Lockfile';
 import { paths } from '../paths';
-import { RunOptions } from '@backstage/cli-common';
+import { getWorkspacesPatterns, RunOptions } from '@backstage/cli-common';
 import fs from 'fs-extra';
 
 /**
@@ -101,7 +101,7 @@ export async function detectPackageManager(): Promise<PackageManager> {
     const packageJson = await fs.readJson(
       paths.resolveTargetRoot('package.json'),
     );
-    if (packageJson.workspaces) {
+    if (getWorkspacesPatterns(packageJson).length > 0) {
       // technically this could be NPM as well
       return await Yarn.create();
     }
diff --git a/packages/cli-node/src/pacman/yarn/Yarn.test.ts b/packages/cli-node/src/pacman/yarn/Yarn.test.ts
index 9bf866b821..f13b5a0296 100644
--- a/packages/cli-node/src/pacman/yarn/Yarn.test.ts
+++ b/packages/cli-node/src/pacman/yarn/Yarn.test.ts
@@ -30,7 +30,7 @@ const allYarnVersions = [yarnClassic, yarnBerry];
 
 describe('Yarn', () => {
   describe.each(allYarnVersions)('%s.getMonorepoPackages', yarn => {
-    it('should detect a monorepo', async () => {
+    it('should detect a monorepo with workspaces.packages field', async () => {
       mockDir.setContent({
         'package.json': JSON.stringify({
           name: 'foo',
@@ -41,6 +41,15 @@ describe('Yarn', () => {
       });
       await expect(yarn.getMonorepoPackages()).resolves.toEqual(['packages/*']);
     });
+    it('should detect a monorepo', async () => {
+      mockDir.setContent({
+        'package.json': JSON.stringify({
+          name: 'foo',
+          workspaces: ['packages/*'],
+        }),
+      });
+      await expect(yarn.getMonorepoPackages()).resolves.toEqual(['packages/*']);
+    });
 
     it('should detect a non-monorepo', async () => {
       mockDir.setContent({
diff --git a/packages/cli-node/src/pacman/yarn/Yarn.ts b/packages/cli-node/src/pacman/yarn/Yarn.ts
index a6544344ca..4658a256c6 100644
--- a/packages/cli-node/src/pacman/yarn/Yarn.ts
+++ b/packages/cli-node/src/pacman/yarn/Yarn.ts
@@ -25,6 +25,7 @@ import { YarnVersion } from './types';
 import fs from 'fs-extra';
 import { paths } from '../../paths';
 import { run, runOutput, RunOptions } from '@backstage/cli-common';
+import { getWorkspacesPatterns } from '@backstage/cli-common';
 
 export class Yarn implements PackageManager {
   constructor(private readonly yarnVersion: YarnVersion) {}
@@ -50,7 +51,7 @@ export class Yarn implements PackageManager {
     const rootPackageJsonPath = paths.resolveTargetRoot('package.json');
     try {
       const pkg = await fs.readJson(rootPackageJsonPath);
-      return pkg?.workspaces?.packages || [];
+      return getWorkspacesPatterns(pkg);
     } catch (error) {
       return [];
     }
diff --git a/packages/cli/config/jest.js b/packages/cli/config/jest.js
index 814f017e1d..09143ac034 100644
--- a/packages/cli/config/jest.js
+++ b/packages/cli/config/jest.js
@@ -20,6 +20,7 @@ const crypto = require('node:crypto');
 const glob = require('node:util').promisify(require('glob'));
 const { version } = require('../package.json');
 const paths = require('@backstage/cli-common').findPaths(process.cwd());
+const { getWorkspacesPatterns } = require('@backstage/cli-common');
 const {
   getJestEnvironment,
   getJestMajorVersion,
@@ -336,11 +337,10 @@ async function getRootConfig() {
     rejectFrontendNetworkRequests,
   };
 
-  const workspacePatterns =
-    rootPkgJson.workspaces && rootPkgJson.workspaces.packages;
+  const workspacePatterns = getWorkspacesPatterns(rootPkgJson);
 
   // Check if we're running within a specific monorepo package. In that case just get the single project config.
-  if (!workspacePatterns || paths.targetRoot !== paths.targetDir) {
+  if (workspacePatterns.length === 0 || paths.targetRoot !== paths.targetDir) {
     return getProjectConfig(
       paths.targetDir,
       {
diff --git a/packages/cli/src/lib/versioning/packages.test.ts b/packages/cli/src/lib/versioning/packages.test.ts
index e823ce8769..8946b8ba2f 100644
--- a/packages/cli/src/lib/versioning/packages.test.ts
+++ b/packages/cli/src/lib/versioning/packages.test.ts
@@ -104,9 +104,7 @@ describe('mapDependencies', () => {
   it('should read dependencies', async () => {
     mockDir.setContent({
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['pkgs/*'],
-        },
+        workspaces: ['pkgs/*'],
       }),
       pkgs: {
         a: {
diff --git a/packages/cli/src/modules/migrate/commands/versions/bump.test.ts b/packages/cli/src/modules/migrate/commands/versions/bump.test.ts
index 202704e030..affd5a9aee 100644
--- a/packages/cli/src/modules/migrate/commands/versions/bump.test.ts
+++ b/packages/cli/src/modules/migrate/commands/versions/bump.test.ts
@@ -160,9 +160,7 @@ describe('bump', () => {
     mockDir.setContent({
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -255,9 +253,7 @@ describe('bump', () => {
     mockDir.setContent({
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -353,9 +349,7 @@ describe('bump', () => {
     mockDir.setContent({
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -459,9 +453,7 @@ describe('bump', () => {
       '.yarnrc.yml': yarnRcMock,
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -572,9 +564,7 @@ describe('bump', () => {
     mockDir.setContent({
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -644,9 +634,7 @@ describe('bump', () => {
     mockDir.setContent({
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -750,9 +738,7 @@ describe('bump', () => {
     mockDir.setContent({
       'yarn.lock': customLockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -865,9 +851,7 @@ describe('bump', () => {
     mockDir.setContent({
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -1099,9 +1083,7 @@ describe('environment variables', () => {
     mockDir.setContent({
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -1192,9 +1174,7 @@ describe('environment variables', () => {
       'custom-manifest.json': JSON.stringify(customManifest),
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -1262,9 +1242,7 @@ describe('environment variables', () => {
       '.yarnrc.yml': yarnRcMock,
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -1337,9 +1315,7 @@ describe('environment variables', () => {
     mockDir.setContent({
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
@@ -1362,9 +1338,7 @@ describe('environment variables', () => {
     mockDir.setContent({
       'yarn.lock': lockfileMock,
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       packages: {
         a: {
diff --git a/packages/cli/src/modules/migrate/commands/versions/migrate.test.ts b/packages/cli/src/modules/migrate/commands/versions/migrate.test.ts
index 936d10e24c..533bdaa954 100644
--- a/packages/cli/src/modules/migrate/commands/versions/migrate.test.ts
+++ b/packages/cli/src/modules/migrate/commands/versions/migrate.test.ts
@@ -73,9 +73,7 @@ describe('versions:migrate', () => {
   it('should bump to the moved version when the package is moved', async () => {
     mockDir.setContent({
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       node_modules: {
         '@backstage': {
@@ -177,9 +175,7 @@ describe('versions:migrate', () => {
   it('should replace the occurrences of the moved package in files inside the correct package', async () => {
     mockDir.setContent({
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       node_modules: {
         '@backstage': {
@@ -264,9 +260,7 @@ describe('versions:migrate', () => {
   it('should replace occurrences of changed packages, and is careful', async () => {
     mockDir.setContent({
       'package.json': JSON.stringify({
-        workspaces: {
-          packages: ['packages/*'],
-        },
+        workspaces: ['packages/*'],
       }),
       node_modules: {
         '@backstage': {

From b2d9d78c27e1db07773945315819d9518684d437 Mon Sep 17 00:00:00 2001
From: Gabriel Dugny <gabriel.dugny@believe.com>
Date: Thu, 29 Jan 2026 17:43:29 +0100
Subject: [PATCH 3/6] fix: defensive package.json reading

Signed-off-by: Gabriel Dugny <gabriel.dugny@believe.com>
---
 packages/cli-common/report.api.md             |  2 +-
 packages/cli-common/src/index.ts              |  3 +-
 packages/cli-common/src/paths.test.ts         |  6 +-
 packages/cli-common/src/paths.ts              | 20 +-----
 packages/cli-common/src/workspaces.test.ts    | 69 +++++++++++++++++++
 packages/cli-common/src/workspaces.ts         | 63 +++++++++++++++++
 .../src/pacman/PackageManager.test.ts         |  4 +-
 7 files changed, 142 insertions(+), 25 deletions(-)
 create mode 100644 packages/cli-common/src/workspaces.test.ts
 create mode 100644 packages/cli-common/src/workspaces.ts

diff --git a/packages/cli-common/report.api.md b/packages/cli-common/report.api.md
index ec146f78c4..324b28880b 100644
--- a/packages/cli-common/report.api.md
+++ b/packages/cli-common/report.api.md
@@ -24,7 +24,7 @@ export class ExitCodeError extends CustomErrorBase {
 export function findPaths(searchDir: string): Paths;
 
 // @public
-export function getWorkspacesPatterns(pkgJson: any): string[];
+export function getWorkspacesPatterns(pkgJson: unknown): string[];
 
 // @public
 export function isChildPath(base: string, path: string): boolean;
diff --git a/packages/cli-common/src/index.ts b/packages/cli-common/src/index.ts
index 146af314cd..e142030b88 100644
--- a/packages/cli-common/src/index.ts
+++ b/packages/cli-common/src/index.ts
@@ -20,7 +20,8 @@
  * @packageDocumentation
  */
 
-export { findPaths, getWorkspacesPatterns, BACKSTAGE_JSON } from './paths';
+export { findPaths, BACKSTAGE_JSON } from './paths';
+export { getWorkspacesPatterns } from './workspaces';
 export { isChildPath } from './isChildPath';
 export type { Paths, ResolveFunc } from './paths';
 export { bootstrapEnvProxyAgents } from './proxyBootstrap';
diff --git a/packages/cli-common/src/paths.test.ts b/packages/cli-common/src/paths.test.ts
index 6ade904e12..f3d7b9b873 100644
--- a/packages/cli-common/src/paths.test.ts
+++ b/packages/cli-common/src/paths.test.ts
@@ -98,7 +98,9 @@ describe('paths', () => {
   });
 
   it('findPaths should find workspace root with object', () => {
-    jest.spyOn(JSON, 'parse').mockReturnValue({ workspaces: { packages: [] } });
+    jest
+      .spyOn(JSON, 'parse')
+      .mockReturnValue({ workspaces: { packages: ['packages/*'] } });
     jest.spyOn(process, 'cwd').mockReturnValue(__dirname);
 
     const paths = findPaths(__dirname);
@@ -110,7 +112,7 @@ describe('paths', () => {
   });
 
   it('findPaths should find workspace root with array', () => {
-    jest.spyOn(JSON, 'parse').mockReturnValue({ workspaces: [] });
+    jest.spyOn(JSON, 'parse').mockReturnValue({ workspaces: ['packages/*'] });
     jest.spyOn(process, 'cwd').mockReturnValue(__dirname);
 
     const paths = findPaths(__dirname);
diff --git a/packages/cli-common/src/paths.ts b/packages/cli-common/src/paths.ts
index 557af7ccca..efbb05c7bb 100644
--- a/packages/cli-common/src/paths.ts
+++ b/packages/cli-common/src/paths.ts
@@ -16,6 +16,7 @@
 
 import fs from 'node:fs';
 import { dirname, resolve as resolvePath } from 'node:path';
+import { getWorkspacesPatterns } from './workspaces';
 
 /**
  * A function that takes a set of path fragments and resolves them into a
@@ -107,25 +108,6 @@ export function findOwnRootDir(ownDir: string) {
   return resolvePath(ownDir, '../..');
 }
 
-/**
- * Gets the workspaces pattern from a package.json object.
- * @param pkgJson - The package.json object to get the workspaces pattern from.
- * @returns The workspaces patterns (glob not resolved).
- * @public
- */
-export function getWorkspacesPatterns(pkgJson: any): string[] {
-  if (Array.isArray(pkgJson.workspaces)) {
-    return pkgJson.workspaces;
-  } else if (
-    typeof pkgJson.workspaces === 'object' &&
-    pkgJson.workspaces !== null &&
-    Array.isArray(pkgJson.workspaces.packages)
-  ) {
-    return pkgJson.workspaces.packages;
-  }
-  return [];
-}
-
 /**
  * Find paths related to a package and its execution context.
  *
diff --git a/packages/cli-common/src/workspaces.test.ts b/packages/cli-common/src/workspaces.test.ts
new file mode 100644
index 0000000000..7725aa7e6a
--- /dev/null
+++ b/packages/cli-common/src/workspaces.test.ts
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2026 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { getWorkspacesPatterns } from './workspaces';
+
+describe('getWorkspacesPatterns', () => {
+  it('returns empty array when pkgJson has no workspaces key', () => {
+    expect(getWorkspacesPatterns({ name: 'pkg' })).toEqual([]);
+  });
+
+  it('returns patterns when workspaces is array form', () => {
+    const patterns = ['packages/*', 'apps/*'];
+    expect(getWorkspacesPatterns({ workspaces: patterns })).toEqual(patterns);
+  });
+
+  it('returns patterns when workspaces is object form with packages', () => {
+    const patterns = ['packages/*'];
+    expect(
+      getWorkspacesPatterns({ workspaces: { packages: patterns } }),
+    ).toEqual(patterns);
+  });
+
+  it('returns empty array when workspaces is object without packages array', () => {
+    expect(getWorkspacesPatterns({ workspaces: {} })).toEqual([]);
+    expect(getWorkspacesPatterns({ workspaces: { noMatch: [] } })).toEqual([]);
+  });
+
+  it('throws when pkgJson is not an object', () => {
+    expect(() => getWorkspacesPatterns(null)).toThrow(
+      'pkgJson must be an object',
+    );
+    expect(() => getWorkspacesPatterns('string')).toThrow(
+      'pkgJson must be an object',
+    );
+    expect(() => getWorkspacesPatterns(42)).toThrow(
+      'pkgJson must be an object',
+    );
+  });
+
+  it('throws when workspaces array contains non-strings', () => {
+    expect(() => getWorkspacesPatterns({ workspaces: ['a', 1, 'b'] })).toThrow(
+      'must be an array of strings',
+    );
+    expect(() => getWorkspacesPatterns({ workspaces: [null] })).toThrow(
+      'must be an array of strings',
+    );
+  });
+
+  it('throws when workspaces.packages contains non-strings', () => {
+    expect(() =>
+      getWorkspacesPatterns({
+        workspaces: { packages: ['a', 1] },
+      }),
+    ).toThrow('must be an array of strings');
+  });
+});
diff --git a/packages/cli-common/src/workspaces.ts b/packages/cli-common/src/workspaces.ts
new file mode 100644
index 0000000000..17fca511a4
--- /dev/null
+++ b/packages/cli-common/src/workspaces.ts
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2026 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+function assertStringArray(
+  value: unknown,
+  field: string,
+): asserts value is string[] {
+  if (!Array.isArray(value)) {
+    throw new Error(`${field} must be an array`);
+  }
+  if (!value.every((item): item is string => typeof item === 'string')) {
+    throw new Error(`${field} must be an array of strings`);
+  }
+}
+
+/**
+ * Gets the workspaces patterns from a package.json object.
+ *
+ * Supports both the array form (`"workspaces": ["packages/*"]`) and the object
+ * form (`"workspaces": { "packages": ["packages/*"] }`) from npm/yarn.
+ *
+ * @param pkgJson - The package.json object. Type as `unknown` so callers must pass parsed JSON; an object type check is performed.
+ * @returns The workspaces patterns (globs not resolved). Empty array if none.
+ * @throws Error if `pkgJson` is not an object or workspaces/packages contain non-strings.
+ * @public
+ */
+export function getWorkspacesPatterns(pkgJson: unknown): string[] {
+  if (typeof pkgJson !== 'object' || pkgJson === null) {
+    throw new Error('pkgJson must be an object');
+  }
+  if (!('workspaces' in pkgJson)) {
+    return [];
+  }
+
+  const workspaces = pkgJson.workspaces;
+  if (Array.isArray(workspaces)) {
+    assertStringArray(workspaces, 'pkgJson.workspaces');
+    return workspaces;
+  }
+  if (
+    typeof workspaces === 'object' &&
+    workspaces !== null &&
+    'packages' in workspaces &&
+    Array.isArray(workspaces.packages)
+  ) {
+    assertStringArray(workspaces.packages, 'pkgJson.workspaces.packages');
+    return workspaces.packages;
+  }
+  return [];
+}
diff --git a/packages/cli-node/src/pacman/PackageManager.test.ts b/packages/cli-node/src/pacman/PackageManager.test.ts
index fd7ace5bcb..e394d2ed60 100644
--- a/packages/cli-node/src/pacman/PackageManager.test.ts
+++ b/packages/cli-node/src/pacman/PackageManager.test.ts
@@ -48,7 +48,7 @@ describe('PackageManager', () => {
           'package.json': JSON.stringify({
             name: 'foo',
             workspaces: {
-              packages: [],
+              packages: ['packages/*'],
             },
           }),
         });
@@ -59,7 +59,7 @@ describe('PackageManager', () => {
         mockDir.setContent({
           'package.json': JSON.stringify({
             name: 'foo',
-            workspaces: [],
+            workspaces: ['packages/*'],
           }),
         });
         await detectPackageManager();

From 0e5fd0fd27f2fb5bec9738f02862a4854210c22c Mon Sep 17 00:00:00 2001
From: Gabriel Dugny <gabriel.dugny@believe.com>
Date: Sun, 22 Feb 2026 17:00:06 +0100
Subject: [PATCH 4/6] Revert most changes

Signed-off-by: Gabriel Dugny <gabriel.dugny@believe.com>
---
 .changeset/slick-dogs-pay.md                  |  1 -
 packages/cli-common/report.api.md             |  3 -
 packages/cli-common/src/index.ts              |  1 -
 packages/cli-common/src/paths.ts              |  3 +-
 packages/cli-common/src/workspaces.test.ts    | 69 -------------------
 packages/cli-common/src/workspaces.ts         | 63 -----------------
 packages/cli-node/src/monorepo/isMonoRepo.ts  |  8 ++-
 .../src/pacman/PackageManager.test.ts         |  6 +-
 .../cli-node/src/pacman/PackageManager.ts     |  4 +-
 packages/cli-node/src/pacman/yarn/Yarn.ts     |  6 +-
 packages/cli/config/jest.js                   |  6 +-
 11 files changed, 18 insertions(+), 152 deletions(-)
 delete mode 100644 packages/cli-common/src/workspaces.test.ts
 delete mode 100644 packages/cli-common/src/workspaces.ts

diff --git a/.changeset/slick-dogs-pay.md b/.changeset/slick-dogs-pay.md
index f75382aa02..409670601e 100644
--- a/.changeset/slick-dogs-pay.md
+++ b/.changeset/slick-dogs-pay.md
@@ -1,5 +1,4 @@
 ---
-'@backstage/cli-common': patch
 '@backstage/create-app': patch
 '@backstage/cli-node': patch
 '@backstage/cli': patch
diff --git a/packages/cli-common/report.api.md b/packages/cli-common/report.api.md
index 324b28880b..96475c6bd1 100644
--- a/packages/cli-common/report.api.md
+++ b/packages/cli-common/report.api.md
@@ -23,9 +23,6 @@ export class ExitCodeError extends CustomErrorBase {
 // @public
 export function findPaths(searchDir: string): Paths;
 
-// @public
-export function getWorkspacesPatterns(pkgJson: unknown): string[];
-
 // @public
 export function isChildPath(base: string, path: string): boolean;
 
diff --git a/packages/cli-common/src/index.ts b/packages/cli-common/src/index.ts
index e142030b88..d11601b044 100644
--- a/packages/cli-common/src/index.ts
+++ b/packages/cli-common/src/index.ts
@@ -21,7 +21,6 @@
  */
 
 export { findPaths, BACKSTAGE_JSON } from './paths';
-export { getWorkspacesPatterns } from './workspaces';
 export { isChildPath } from './isChildPath';
 export type { Paths, ResolveFunc } from './paths';
 export { bootstrapEnvProxyAgents } from './proxyBootstrap';
diff --git a/packages/cli-common/src/paths.ts b/packages/cli-common/src/paths.ts
index efbb05c7bb..5da2d596a4 100644
--- a/packages/cli-common/src/paths.ts
+++ b/packages/cli-common/src/paths.ts
@@ -16,7 +16,6 @@
 
 import fs from 'node:fs';
 import { dirname, resolve as resolvePath } from 'node:path';
-import { getWorkspacesPatterns } from './workspaces';
 
 /**
  * A function that takes a set of path fragments and resolves them into a
@@ -142,7 +141,7 @@ export function findPaths(searchDir: string): Paths {
           try {
             const content = fs.readFileSync(path, 'utf8');
             const data = JSON.parse(content);
-            return getWorkspacesPatterns(data).length > 0;
+            return Boolean(data.workspaces);
           } catch (error) {
             throw new Error(
               `Failed to parse package.json file while searching for root, ${error}`,
diff --git a/packages/cli-common/src/workspaces.test.ts b/packages/cli-common/src/workspaces.test.ts
deleted file mode 100644
index 7725aa7e6a..0000000000
--- a/packages/cli-common/src/workspaces.test.ts
+++ /dev/null
@@ -1,69 +0,0 @@
-/*
- * Copyright 2026 The Backstage Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import { getWorkspacesPatterns } from './workspaces';
-
-describe('getWorkspacesPatterns', () => {
-  it('returns empty array when pkgJson has no workspaces key', () => {
-    expect(getWorkspacesPatterns({ name: 'pkg' })).toEqual([]);
-  });
-
-  it('returns patterns when workspaces is array form', () => {
-    const patterns = ['packages/*', 'apps/*'];
-    expect(getWorkspacesPatterns({ workspaces: patterns })).toEqual(patterns);
-  });
-
-  it('returns patterns when workspaces is object form with packages', () => {
-    const patterns = ['packages/*'];
-    expect(
-      getWorkspacesPatterns({ workspaces: { packages: patterns } }),
-    ).toEqual(patterns);
-  });
-
-  it('returns empty array when workspaces is object without packages array', () => {
-    expect(getWorkspacesPatterns({ workspaces: {} })).toEqual([]);
-    expect(getWorkspacesPatterns({ workspaces: { noMatch: [] } })).toEqual([]);
-  });
-
-  it('throws when pkgJson is not an object', () => {
-    expect(() => getWorkspacesPatterns(null)).toThrow(
-      'pkgJson must be an object',
-    );
-    expect(() => getWorkspacesPatterns('string')).toThrow(
-      'pkgJson must be an object',
-    );
-    expect(() => getWorkspacesPatterns(42)).toThrow(
-      'pkgJson must be an object',
-    );
-  });
-
-  it('throws when workspaces array contains non-strings', () => {
-    expect(() => getWorkspacesPatterns({ workspaces: ['a', 1, 'b'] })).toThrow(
-      'must be an array of strings',
-    );
-    expect(() => getWorkspacesPatterns({ workspaces: [null] })).toThrow(
-      'must be an array of strings',
-    );
-  });
-
-  it('throws when workspaces.packages contains non-strings', () => {
-    expect(() =>
-      getWorkspacesPatterns({
-        workspaces: { packages: ['a', 1] },
-      }),
-    ).toThrow('must be an array of strings');
-  });
-});
diff --git a/packages/cli-common/src/workspaces.ts b/packages/cli-common/src/workspaces.ts
deleted file mode 100644
index 17fca511a4..0000000000
--- a/packages/cli-common/src/workspaces.ts
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * Copyright 2026 The Backstage Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-function assertStringArray(
-  value: unknown,
-  field: string,
-): asserts value is string[] {
-  if (!Array.isArray(value)) {
-    throw new Error(`${field} must be an array`);
-  }
-  if (!value.every((item): item is string => typeof item === 'string')) {
-    throw new Error(`${field} must be an array of strings`);
-  }
-}
-
-/**
- * Gets the workspaces patterns from a package.json object.
- *
- * Supports both the array form (`"workspaces": ["packages/*"]`) and the object
- * form (`"workspaces": { "packages": ["packages/*"] }`) from npm/yarn.
- *
- * @param pkgJson - The package.json object. Type as `unknown` so callers must pass parsed JSON; an object type check is performed.
- * @returns The workspaces patterns (globs not resolved). Empty array if none.
- * @throws Error if `pkgJson` is not an object or workspaces/packages contain non-strings.
- * @public
- */
-export function getWorkspacesPatterns(pkgJson: unknown): string[] {
-  if (typeof pkgJson !== 'object' || pkgJson === null) {
-    throw new Error('pkgJson must be an object');
-  }
-  if (!('workspaces' in pkgJson)) {
-    return [];
-  }
-
-  const workspaces = pkgJson.workspaces;
-  if (Array.isArray(workspaces)) {
-    assertStringArray(workspaces, 'pkgJson.workspaces');
-    return workspaces;
-  }
-  if (
-    typeof workspaces === 'object' &&
-    workspaces !== null &&
-    'packages' in workspaces &&
-    Array.isArray(workspaces.packages)
-  ) {
-    assertStringArray(workspaces.packages, 'pkgJson.workspaces.packages');
-    return workspaces.packages;
-  }
-  return [];
-}
diff --git a/packages/cli-node/src/monorepo/isMonoRepo.ts b/packages/cli-node/src/monorepo/isMonoRepo.ts
index 9cb19ea62f..c58b3d00ce 100644
--- a/packages/cli-node/src/monorepo/isMonoRepo.ts
+++ b/packages/cli-node/src/monorepo/isMonoRepo.ts
@@ -14,12 +14,14 @@
  * limitations under the License.
  */
 
-import { getWorkspacesPatterns } from '@backstage/cli-common';
 import { paths } from '../paths';
 import fs from 'fs-extra';
 
 /**
- * Returns try if the current project is a monorepo.
+ * Returns true if the current project is a monorepo.
+ *
+ * Uses a simple presence check on the `workspaces` field. Empty or invalid
+ * workspace config is treated as a monorepo; we do not validate patterns.
  *
  * @public
  */
@@ -27,7 +29,7 @@ export async function isMonoRepo(): Promise<boolean> {
   const rootPackageJsonPath = paths.resolveTargetRoot('package.json');
   try {
     const pkg = await fs.readJson(rootPackageJsonPath);
-    return getWorkspacesPatterns(pkg).length > 0;
+    return Boolean(pkg?.workspaces);
   } catch (error) {
     return false;
   }
diff --git a/packages/cli-node/src/pacman/PackageManager.test.ts b/packages/cli-node/src/pacman/PackageManager.test.ts
index e394d2ed60..f704610ab2 100644
--- a/packages/cli-node/src/pacman/PackageManager.test.ts
+++ b/packages/cli-node/src/pacman/PackageManager.test.ts
@@ -43,19 +43,19 @@ describe('PackageManager', () => {
         expect(mockYarnCreate).toHaveBeenCalled();
       });
 
-      it('should detect via root package.json workspaces with legacy workspaces.packages field', async () => {
+      it('should detect via root package.json workspaces', async () => {
         mockDir.setContent({
           'package.json': JSON.stringify({
             name: 'foo',
             workspaces: {
-              packages: ['packages/*'],
+              packages: [],
             },
           }),
         });
         await detectPackageManager();
         expect(mockYarnCreate).toHaveBeenCalled();
       });
-      it('should detect via root package.json workspaces', async () => {
+      it('should detect via root package.json workspaces (array form)', async () => {
         mockDir.setContent({
           'package.json': JSON.stringify({
             name: 'foo',
diff --git a/packages/cli-node/src/pacman/PackageManager.ts b/packages/cli-node/src/pacman/PackageManager.ts
index 5693acce06..44c0849705 100644
--- a/packages/cli-node/src/pacman/PackageManager.ts
+++ b/packages/cli-node/src/pacman/PackageManager.ts
@@ -17,7 +17,7 @@
 import { Yarn } from './yarn';
 import { Lockfile } from './Lockfile';
 import { paths } from '../paths';
-import { getWorkspacesPatterns, RunOptions } from '@backstage/cli-common';
+import { RunOptions } from '@backstage/cli-common';
 import fs from 'fs-extra';
 
 /**
@@ -101,7 +101,7 @@ export async function detectPackageManager(): Promise<PackageManager> {
     const packageJson = await fs.readJson(
       paths.resolveTargetRoot('package.json'),
     );
-    if (getWorkspacesPatterns(packageJson).length > 0) {
+    if (packageJson.workspaces) {
       // technically this could be NPM as well
       return await Yarn.create();
     }
diff --git a/packages/cli-node/src/pacman/yarn/Yarn.ts b/packages/cli-node/src/pacman/yarn/Yarn.ts
index 4658a256c6..9c242c90da 100644
--- a/packages/cli-node/src/pacman/yarn/Yarn.ts
+++ b/packages/cli-node/src/pacman/yarn/Yarn.ts
@@ -25,7 +25,6 @@ import { YarnVersion } from './types';
 import fs from 'fs-extra';
 import { paths } from '../../paths';
 import { run, runOutput, RunOptions } from '@backstage/cli-common';
-import { getWorkspacesPatterns } from '@backstage/cli-common';
 
 export class Yarn implements PackageManager {
   constructor(private readonly yarnVersion: YarnVersion) {}
@@ -51,7 +50,10 @@ export class Yarn implements PackageManager {
     const rootPackageJsonPath = paths.resolveTargetRoot('package.json');
     try {
       const pkg = await fs.readJson(rootPackageJsonPath);
-      return getWorkspacesPatterns(pkg);
+      const workspaces = pkg?.workspaces;
+      return Array.isArray(workspaces)
+        ? workspaces
+        : workspaces?.packages ?? [];
     } catch (error) {
       return [];
     }
diff --git a/packages/cli/config/jest.js b/packages/cli/config/jest.js
index 09143ac034..c670f0fe8b 100644
--- a/packages/cli/config/jest.js
+++ b/packages/cli/config/jest.js
@@ -20,7 +20,6 @@ const crypto = require('node:crypto');
 const glob = require('node:util').promisify(require('glob'));
 const { version } = require('../package.json');
 const paths = require('@backstage/cli-common').findPaths(process.cwd());
-const { getWorkspacesPatterns } = require('@backstage/cli-common');
 const {
   getJestEnvironment,
   getJestMajorVersion,
@@ -337,10 +336,11 @@ async function getRootConfig() {
     rejectFrontendNetworkRequests,
   };
 
-  const workspacePatterns = getWorkspacesPatterns(rootPkgJson);
+  const ws = rootPkgJson.workspaces;
+  const workspacePatterns = Array.isArray(ws) ? ws : ws?.packages;
 
   // Check if we're running within a specific monorepo package. In that case just get the single project config.
-  if (workspacePatterns.length === 0 || paths.targetRoot !== paths.targetDir) {
+  if (!workspacePatterns || paths.targetRoot !== paths.targetDir) {
     return getProjectConfig(
       paths.targetDir,
       {

From bc6c024a4ce0bc4cced64f9a7f83403c67ff7523 Mon Sep 17 00:00:00 2001
From: Gabriel Dugny <gabriel.dugny@believe.com>
Date: Sun, 22 Feb 2026 17:26:35 +0100
Subject: [PATCH 5/6] chore: remove PackageManager getMonorepoPackages

Unused, prefer @manypkg/get-packages's getPackages instead.

Signed-off-by: Gabriel Dugny <gabriel.dugny@believe.com>
---
 .../cli-node/src/pacman/PackageManager.ts     |  6 --
 .../cli-node/src/pacman/yarn/Yarn.test.ts     | 68 -------------------
 packages/cli-node/src/pacman/yarn/Yarn.ts     | 15 ----
 3 files changed, 89 deletions(-)
 delete mode 100644 packages/cli-node/src/pacman/yarn/Yarn.test.ts

diff --git a/packages/cli-node/src/pacman/PackageManager.ts b/packages/cli-node/src/pacman/PackageManager.ts
index 44c0849705..0029652544 100644
--- a/packages/cli-node/src/pacman/PackageManager.ts
+++ b/packages/cli-node/src/pacman/PackageManager.ts
@@ -49,12 +49,6 @@ export interface PackageManager {
   /** The file name of the lockfile used by the package manager. */
   lockfileName(): string;
 
-  /**
-   * If this repo is a monorepo, returns the patterns specified by the package
-   * manager's monorepo configuration. Does not attempt to resolve any globs.
-   */
-  getMonorepoPackages(): Promise<string[]>;
-
   /** Uses the package manager to run a command in the repo. */
   run(args: string[], options?: RunOptions): Promise<void>;
 
diff --git a/packages/cli-node/src/pacman/yarn/Yarn.test.ts b/packages/cli-node/src/pacman/yarn/Yarn.test.ts
deleted file mode 100644
index f13b5a0296..0000000000
--- a/packages/cli-node/src/pacman/yarn/Yarn.test.ts
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
- * Copyright 2024 The Backstage Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import { createMockDirectory } from '@backstage/backend-test-utils';
-import { Yarn } from './Yarn';
-
-const mockDir = createMockDirectory();
-
-jest.mock('../../paths', () => ({
-  ...jest.requireActual('../../paths'),
-  paths: { resolveTargetRoot: (...args: string[]) => mockDir.resolve(...args) },
-}));
-
-const yarnClassic = new Yarn({ version: '1.0.0', codename: 'classic' });
-const yarnBerry = new Yarn({ version: '3.0.0', codename: 'berry' });
-const allYarnVersions = [yarnClassic, yarnBerry];
-
-describe('Yarn', () => {
-  describe.each(allYarnVersions)('%s.getMonorepoPackages', yarn => {
-    it('should detect a monorepo with workspaces.packages field', async () => {
-      mockDir.setContent({
-        'package.json': JSON.stringify({
-          name: 'foo',
-          workspaces: {
-            packages: ['packages/*'],
-          },
-        }),
-      });
-      await expect(yarn.getMonorepoPackages()).resolves.toEqual(['packages/*']);
-    });
-    it('should detect a monorepo', async () => {
-      mockDir.setContent({
-        'package.json': JSON.stringify({
-          name: 'foo',
-          workspaces: ['packages/*'],
-        }),
-      });
-      await expect(yarn.getMonorepoPackages()).resolves.toEqual(['packages/*']);
-    });
-
-    it('should detect a non-monorepo', async () => {
-      mockDir.setContent({
-        'package.json': JSON.stringify({
-          name: 'foo',
-        }),
-      });
-      await expect(yarn.getMonorepoPackages()).resolves.toEqual([]);
-    });
-
-    it('should return false if package.json is missing', async () => {
-      mockDir.setContent({});
-      await expect(yarn.getMonorepoPackages()).resolves.toEqual([]);
-    });
-  });
-});
diff --git a/packages/cli-node/src/pacman/yarn/Yarn.ts b/packages/cli-node/src/pacman/yarn/Yarn.ts
index 9c242c90da..7aee7bdebf 100644
--- a/packages/cli-node/src/pacman/yarn/Yarn.ts
+++ b/packages/cli-node/src/pacman/yarn/Yarn.ts
@@ -22,8 +22,6 @@ import {
 import { PackageInfo, PackageManager } from '../PackageManager';
 import { Lockfile } from '../Lockfile';
 import { YarnVersion } from './types';
-import fs from 'fs-extra';
-import { paths } from '../../paths';
 import { run, runOutput, RunOptions } from '@backstage/cli-common';
 
 export class Yarn implements PackageManager {
@@ -46,19 +44,6 @@ export class Yarn implements PackageManager {
     return 'yarn.lock';
   }
 
-  async getMonorepoPackages() {
-    const rootPackageJsonPath = paths.resolveTargetRoot('package.json');
-    try {
-      const pkg = await fs.readJson(rootPackageJsonPath);
-      const workspaces = pkg?.workspaces;
-      return Array.isArray(workspaces)
-        ? workspaces
-        : workspaces?.packages ?? [];
-    } catch (error) {
-      return [];
-    }
-  }
-
   async pack(out: string, packageDir: string) {
     const outArg =
       this.yarnVersion.codename === 'classic' ? '--filename' : '--out';

From 37a309e7e20afd33e5ec1bac2553ca5b2b3da9a8 Mon Sep 17 00:00:00 2001
From: Gabriel Dugny <gabriel@dugny.me>
Date: Fri, 27 Feb 2026 12:04:16 +0100
Subject: [PATCH 6/6] Update .changeset/slow-items-pull.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Gabriel Dugny <gabriel@dugny.me>
---
 .changeset/slow-items-pull.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.changeset/slow-items-pull.md b/.changeset/slow-items-pull.md
index 50f4897fa5..e3fe6e26c5 100644
--- a/.changeset/slow-items-pull.md
+++ b/.changeset/slow-items-pull.md
@@ -2,7 +2,7 @@
 '@backstage/create-app': patch
 ---
 
-Replace `package.json` deprecated `workspaces.packages` by `workspaces`
+Replace deprecated `workspaces.packages` with `workspaces` in `package.json`
 
 This change is **not** required, but you can edit your main `package.json`, to fit the more modern & more common pattern: