diff --git a/__tests__/required.test.ts b/__tests__/required.test.ts
index 0c6f447..05ba94d 100644
--- a/__tests__/required.test.ts
+++ b/__tests__/required.test.ts
@@ -9,6 +9,7 @@ describe('required', () => {
   let event: WorkflowRunCompletedEvent
 
   beforeEach(() => {
+    process.env.GITHUB_REPOSITORY = 'owner/repo' // Setting GITHUB_REPOSITORY environment variable
     mockOctokit = {
       rest: {
         repos: {
@@ -16,7 +17,9 @@ describe('required', () => {
         },
         actions: {
           getWorkflowRun: jest.fn(),
-          listWorkflowRunsForRepo: jest.fn()
+          listWorkflowRunsForRepo: jest.fn().mockImplementation(() => {
+            return Promise.resolve({ data: undefined }) // Simulating undefined data scenario
+          })
         }
       }
     }
diff --git a/src/required.ts b/src/required.ts
index 2eb11b3..d504244 100644
--- a/src/required.ts
+++ b/src/required.ts
@@ -23,6 +23,11 @@ export async function required({
     run_id: event.workflow_run.id
   })
 
+  // Validate workflow data for undefined before accessing properties
+  if (!workflow.data) {
+    throw new Error('Workflow data is undefined.')
+  }
+
   const head_sha = workflow.data.head_sha
 
   console.log(`Processing ${workflow.data.name} ${workflow.data.html_url}`)
@@ -41,6 +46,11 @@ export async function required({
       per_page: 100
     })
 
+    // Validate workflowRuns data for undefined before accessing properties
+    if (!workflowRuns.data || !workflowRuns.data.workflow_runs) {
+      throw new Error('Workflow runs data is undefined.')
+    }
+
     const selectedWorkflows = workflowRuns.data.workflow_runs.filter(
       w => w.name !== undefined && w.name !== null && workflows.includes(w.name)
     )