diff --git a/src/create-prompt/index.ts b/src/create-prompt/index.ts
index 82d1f41..cd55de2 100644
--- a/src/create-prompt/index.ts
+++ b/src/create-prompt/index.ts
@@ -277,8 +277,6 @@ export function prepareContext(
         throw new Error(
           "ISSUE_NUMBER is required for issue_comment event for issues",
         );
-      } else if (!claudeBranch) {
-        throw new Error("CLAUDE_BRANCH is required for issue_comment event");
       }
 
       eventData = {
@@ -288,7 +286,7 @@ export function prepareContext(
         baseBranch,
         issueNumber,
         commentBody,
-        claudeBranch,
+        ...(claudeBranch && { claudeBranch }),
       };
       break;
 
@@ -305,10 +303,6 @@ export function prepareContext(
       if (!baseBranch) {
         throw new Error("BASE_BRANCH is required for issues event");
       }
-      if (!claudeBranch) {
-        throw new Error("CLAUDE_BRANCH is required for issues event");
-      }
-
       if (eventAction === "assigned") {
         if (!assigneeTrigger && !directPrompt) {
           throw new Error(
@@ -322,7 +316,7 @@ export function prepareContext(
           issueNumber,
           baseBranch,
           ...(assigneeTrigger && { assigneeTrigger }),
-          claudeBranch,
+          ...(claudeBranch && { claudeBranch }),
         };
       } else if (eventAction === "labeled") {
         if (!labelTrigger) {
@@ -334,7 +328,7 @@ export function prepareContext(
           isPR: false,
           issueNumber,
           baseBranch,
-          claudeBranch,
+          ...(claudeBranch && { claudeBranch }),
           labelTrigger,
         };
       } else if (eventAction === "opened") {
diff --git a/test/prepare-context.test.ts b/test/prepare-context.test.ts
index fb2e9d0..c205eb4 100644
--- a/test/prepare-context.test.ts
+++ b/test/prepare-context.test.ts
@@ -69,10 +69,19 @@ describe("parseEnvVarsWithContext", () => {
         }
       });
 
-      test("should throw error when CLAUDE_BRANCH is missing", () => {
-        expect(() =>
-          prepareContext(mockIssueCommentContext, "12345", "main"),
-        ).toThrow("CLAUDE_BRANCH is required for issue_comment event");
+      test("should allow missing CLAUDE_BRANCH and omit it from event data", () => {
+        const result = prepareContext(
+          mockIssueCommentContext,
+          "12345",
+          "main",
+        );
+
+        if (
+          result.eventData.eventName === "issue_comment" &&
+          !result.eventData.isPR
+        ) {
+          expect(result.eventData.claudeBranch).toBeUndefined();
+        }
       });
 
       test("should throw error when BASE_BRANCH is missing", () => {
@@ -203,10 +212,12 @@ describe("parseEnvVarsWithContext", () => {
       }
     });
 
-    test("should throw error when CLAUDE_BRANCH is missing for issues", () => {
-      expect(() =>
-        prepareContext(mockIssueOpenedContext, "12345", "main"),
-      ).toThrow("CLAUDE_BRANCH is required for issues event");
+    test("should allow issues event without CLAUDE_BRANCH", () => {
+      const result = prepareContext(mockIssueOpenedContext, "12345", "main");
+
+      if (result.eventData.eventName === "issues") {
+        expect(result.eventData.claudeBranch).toBeUndefined();
+      }
     });
 
     test("should throw error when BASE_BRANCH is missing for issues", () => {