diff --git a/README.md b/README.md
index 84ec19d..52444a6 100644
--- a/README.md
+++ b/README.md
@@ -17,8 +17,9 @@ In your workflow file:
 steps:
   # This action requires an unshallow working copy,
   # so the following prerequisites are necessary:
-  - uses: actions/checkout@v1.1
-  - run: git fetch --prune --unshallow
+  - uses: actions/checkout@v3
+    with:
+      fetch-depth: 0
 
   # Deploy your application
   - uses: 47ng/actions-clever-cloud@v1.1
diff --git a/__tests__/main.test.ts b/__tests__/main.test.ts
index 1c3896e..d478ce8 100644
--- a/__tests__/main.test.ts
+++ b/__tests__/main.test.ts
@@ -19,14 +19,14 @@ test('deploy default application (no arguments)', async () => {
     cleverCLI: 'clever'
   })
 
-  expect(exec).toHaveBeenNthCalledWith(1, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
     'login',
     '--token',
     'token',
     '--secret',
     'secret'
   ])
-  expect(exec).toHaveBeenNthCalledWith(2, 'clever', ['deploy'])
+  expect(exec).toHaveBeenNthCalledWith(3, 'clever', ['deploy'])
   expect(core.setFailed).not.toHaveBeenCalled()
 })
 
@@ -38,14 +38,14 @@ test('deploy application with alias', async () => {
     cleverCLI: 'clever'
   })
 
-  expect(exec).toHaveBeenNthCalledWith(1, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
     'login',
     '--token',
     'token',
     '--secret',
     'secret'
   ])
-  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
     'deploy',
     '--alias',
     'app-alias'
@@ -60,20 +60,20 @@ test('deploy application with app ID', async () => {
     appID: 'app_facade42-cafe-babe-cafe-deadf00dbaad',
     cleverCLI: 'clever'
   })
-  expect(exec).toHaveBeenNthCalledWith(1, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
     'login',
     '--token',
     'token',
     '--secret',
     'secret'
   ])
-  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
     'link',
     'app_facade42-cafe-babe-cafe-deadf00dbaad',
     '--alias',
     'app_facade42-cafe-babe-cafe-deadf00dbaad'
   ])
-  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(4, 'clever', [
     'deploy',
     '--alias',
     'app_facade42-cafe-babe-cafe-deadf00dbaad'
@@ -88,20 +88,20 @@ test('when both app ID and alias are provided, appID takes precedence', async ()
     appID: 'app_facade42-cafe-babe-cafe-deadf00dbaad',
     cleverCLI: 'clever'
   })
-  expect(exec).toHaveBeenNthCalledWith(1, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
     'login',
     '--token',
     'token',
     '--secret',
     'secret'
   ])
-  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
     'link',
     'app_facade42-cafe-babe-cafe-deadf00dbaad',
     '--alias',
     'app_facade42-cafe-babe-cafe-deadf00dbaad'
   ])
-  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(4, 'clever', [
     'deploy',
     '--alias',
     'app_facade42-cafe-babe-cafe-deadf00dbaad'
@@ -118,26 +118,26 @@ test('passing extra env variables, using no input args', async () => {
       egg: 'spam'
     }
   })
-  expect(exec).toHaveBeenNthCalledWith(1, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
     'login',
     '--token',
     'token',
     '--secret',
     'secret'
   ])
-  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
     'env',
     'set',
     'foo',
     'bar'
   ])
-  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(4, 'clever', [
     'env',
     'set',
     'egg',
     'spam'
   ])
-  expect(exec).toHaveBeenNthCalledWith(4, 'clever', ['deploy'])
+  expect(exec).toHaveBeenNthCalledWith(5, 'clever', ['deploy'])
 })
 
 test('passing extra env variables, using appID', async () => {
@@ -151,20 +151,20 @@ test('passing extra env variables, using appID', async () => {
       egg: 'spam'
     }
   })
-  expect(exec).toHaveBeenNthCalledWith(1, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
     'login',
     '--token',
     'token',
     '--secret',
     'secret'
   ])
-  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
     'link',
     'app_facade42-cafe-babe-cafe-deadf00dbaad',
     '--alias',
     'app_facade42-cafe-babe-cafe-deadf00dbaad'
   ])
-  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(4, 'clever', [
     'env',
     'set',
     '--alias',
@@ -172,7 +172,7 @@ test('passing extra env variables, using appID', async () => {
     'foo',
     'bar'
   ])
-  expect(exec).toHaveBeenNthCalledWith(4, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(5, 'clever', [
     'env',
     'set',
     '--alias',
@@ -180,7 +180,7 @@ test('passing extra env variables, using appID', async () => {
     'egg',
     'spam'
   ])
-  expect(exec).toHaveBeenNthCalledWith(5, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(6, 'clever', [
     'deploy',
     '--alias',
     'app_facade42-cafe-babe-cafe-deadf00dbaad'
@@ -198,14 +198,14 @@ test('passing extra env variables, using alias only', async () => {
       egg: 'spam'
     }
   })
-  expect(exec).toHaveBeenNthCalledWith(1, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
     'login',
     '--token',
     'token',
     '--secret',
     'secret'
   ])
-  expect(exec).toHaveBeenNthCalledWith(2, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
     'env',
     'set',
     '--alias',
@@ -213,7 +213,7 @@ test('passing extra env variables, using alias only', async () => {
     'foo',
     'bar'
   ])
-  expect(exec).toHaveBeenNthCalledWith(3, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(4, 'clever', [
     'env',
     'set',
     '--alias',
@@ -221,7 +221,7 @@ test('passing extra env variables, using alias only', async () => {
     'egg',
     'spam'
   ])
-  expect(exec).toHaveBeenNthCalledWith(4, 'clever', [
+  expect(exec).toHaveBeenNthCalledWith(5, 'clever', [
     'deploy',
     '--alias',
     'foo'
diff --git a/src/action.ts b/src/action.ts
index 64f1f6b..867eca6 100644
--- a/src/action.ts
+++ b/src/action.ts
@@ -73,6 +73,23 @@ export function processArguments(): Arguments {
   }
 }
 
+async function checkForShallowCopy(): Promise<void> {
+  let output = ''
+  await exec('git', ['rev-parse', '--is-shallow-repository'], {
+    listeners: {
+      stdout: (data: Buffer) => (output += data.toString())
+    }
+  })
+  if (output.trim() === 'true') {
+    throw new Error(`This action requires an unshallow working copy.
+-> Use the following step before running this action:
+ - uses: actions/checkout@v3
+   with:
+     fetch-depth: 0
+`)
+  }
+}
+
 export default async function run({
   token,
   secret,
@@ -83,6 +100,8 @@ export default async function run({
   extraEnv = {}
 }: Arguments): Promise<void> {
   try {
+    await checkForShallowCopy()
+
     core.debug(`Clever CLI path: ${cleverCLI}`)
 
     // Authenticate (this will only store the credentials at a known location)