diff --git a/__test__/git-command-manager.test.ts b/__test__/git-command-manager.test.ts
index 5b21f31..3d0afec 100644
--- a/__test__/git-command-manager.test.ts
+++ b/__test__/git-command-manager.test.ts
@@ -493,7 +493,7 @@ describe('git user-agent with orchestration ID', () => {
     )
   })
 
-  it('should not append orchestration ID when it becomes empty after sanitization', async () => {
+  it('should sanitize orchestration ID to underscores when it contains only invalid characters', async () => {
     const orchId = '()///'
     process.env['ACTIONS_ORCHESTRATION_ID'] = orchId
 
@@ -520,11 +520,11 @@ describe('git user-agent with orchestration ID', () => {
     // Call a git command to trigger env capture after user-agent is set
     await git.init()
 
-    // Verify the user agent does NOT contain orchestration ID when sanitized ID is empty
+    // Verify the user agent contains orchestration ID with sanitized underscores
     expect(git).toBeDefined()
     expect(capturedEnv).toBeDefined()
     expect(capturedEnv['GIT_HTTP_USER_AGENT']).toBe(
-      'git/2.18 (github-actions-checkout)'
+      'git/2.18 (github-actions-checkout) actions_orchestration_id/_____'
     )
   })
 })
diff --git a/dist/index.js b/dist/index.js
index afcd3f8..4eab86e 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -1213,8 +1213,7 @@ class GitCommandManager {
                 // Sanitize the orchestration ID to ensure it contains only valid characters
                 // Valid characters: 0-9, a-z, _, -, .
                 const sanitizedId = orchId.replace(/[^a-z0-9_.-]/gi, '_');
-                // Only append if sanitized ID contains at least one alphanumeric character
-                if (sanitizedId && /[a-z0-9]/i.test(sanitizedId)) {
+                if (sanitizedId) {
                     gitHttpUserAgent = `${gitHttpUserAgent} actions_orchestration_id/${sanitizedId}`;
                 }
             }
diff --git a/src/git-command-manager.ts b/src/git-command-manager.ts
index ea2302a..eba285a 100644
--- a/src/git-command-manager.ts
+++ b/src/git-command-manager.ts
@@ -738,8 +738,7 @@ class GitCommandManager {
       // Sanitize the orchestration ID to ensure it contains only valid characters
       // Valid characters: 0-9, a-z, _, -, .
       const sanitizedId = orchId.replace(/[^a-z0-9_.-]/gi, '_')
-      // Only append if sanitized ID contains at least one alphanumeric character
-      if (sanitizedId && /[a-z0-9]/i.test(sanitizedId)) {
+      if (sanitizedId) {
         gitHttpUserAgent = `${gitHttpUserAgent} actions_orchestration_id/${sanitizedId}`
       }
     }