diff --git a/__tests__/main.test.ts b/__tests__/main.test.ts
index abfada4..1c3896e 100644
--- a/__tests__/main.test.ts
+++ b/__tests__/main.test.ts
@@ -1,3 +1,5 @@
+// @ts-check
+
 import run from '../src/action'
 
 const core = require('@actions/core')
@@ -9,11 +11,14 @@ jest.mock('@actions/core')
 // --
 
 test('deploy default application (no arguments)', async () => {
+  exec.mockResolvedValue(0)
+
   await run({
     token: 'token',
     secret: 'secret',
     cleverCLI: 'clever'
   })
+
   expect(exec).toHaveBeenNthCalledWith(1, 'clever', [
     'login',
     '--token',
@@ -32,6 +37,7 @@ test('deploy application with alias', async () => {
     alias: 'app-alias',
     cleverCLI: 'clever'
   })
+
   expect(exec).toHaveBeenNthCalledWith(1, 'clever', [
     'login',
     '--token',
@@ -221,3 +227,24 @@ test('passing extra env variables, using alias only', async () => {
     'foo'
   ])
 })
+
+test('deployment failure fails the workflow', async () => {
+  exec.mockResolvedValue(42)
+  await run({
+    token: 'token',
+    secret: 'secret',
+    cleverCLI: 'clever'
+  })
+  expect(core.setFailed).toHaveBeenCalledWith('Deployment failed with code 42')
+})
+
+test('deployment failure with timeout fails the workflow', async () => {
+  exec.mockResolvedValue(42)
+  await run({
+    token: 'token',
+    secret: 'secret',
+    cleverCLI: 'clever',
+    timeout: 10_000
+  })
+  expect(core.setFailed).toHaveBeenCalledWith('Deployment failed with code 42')
+})
diff --git a/src/action.ts b/src/action.ts
index d24e953..bef9866 100644
--- a/src/action.ts
+++ b/src/action.ts
@@ -125,15 +125,21 @@ export default async function run({
           resolve()
         }, timeout)
       })
-      await Promise.race([exec(cleverCLI, args), timeoutPromise])
+      const result = await Promise.race([exec(cleverCLI, args), timeoutPromise])
       if (timeoutID) {
         clearTimeout(timeoutID)
       }
       if (timedOut) {
         core.info('Deployment timed out, moving on with workflow run')
       }
+      if (typeof result === 'number' && result !== 0) {
+        throw new Error(`Deployment failed with code ${result}`)
+      }
     } else {
-      await exec(cleverCLI, args)
+      const code = await exec(cleverCLI, args)
+      if (code !== 0) {
+        throw new Error(`Deployment failed with code ${code}`)
+      }
     }
   } catch (error) {
     if (error instanceof Error) {