diff --git a/src/github/operations/branch.ts b/src/github/operations/branch.ts
index 32a6863..68e8b0e 100644
--- a/src/github/operations/branch.ts
+++ b/src/github/operations/branch.ts
@@ -86,14 +86,18 @@ export async function setupBranch(
 
   // Generate branch name for either an issue or closed/merged PR
   const entityType = isPR ? "pr" : "issue";
-  const timestamp = new Date()
-    .toISOString()
-    .replace(/[:-]/g, "")
-    .replace(/\.\d{3}Z/, "")
-    .split("T")
-    .join("_");
 
-  const newBranch = `${branchPrefix}${entityType}-${entityNumber}-${timestamp}`;
+  // Create Kubernetes-compatible timestamp: lowercase, hyphens only, shorter format
+  const now = new Date();
+  const timestamp = `${now.getFullYear()}${String(now.getMonth() + 1).padStart(2, "0")}${String(now.getDate()).padStart(2, "0")}-${String(now.getHours()).padStart(2, "0")}${String(now.getMinutes()).padStart(2, "0")}`;
+
+  // Ensure branch name is Kubernetes-compatible:
+  // - Lowercase only
+  // - Alphanumeric with hyphens
+  // - No underscores
+  // - Max 50 chars (to allow for prefixes)
+  const branchName = `${branchPrefix}${entityType}-${entityNumber}-${timestamp}`;
+  const newBranch = branchName.toLowerCase().substring(0, 50);
 
   try {
     // Get the SHA of the source branch to verify it exists
diff --git a/test/branch-cleanup.test.ts b/test/branch-cleanup.test.ts
index b5a3df7..2837432 100644
--- a/test/branch-cleanup.test.ts
+++ b/test/branch-cleanup.test.ts
@@ -72,7 +72,7 @@ describe("checkAndCommitOrDeleteBranch", () => {
       mockOctokit,
       "owner",
       "repo",
-      "claude/issue-123-20240101_123456",
+      "claude/issue-123-20240101-1234",
       "main",
       true, // commit signing enabled
     );
@@ -80,7 +80,7 @@ describe("checkAndCommitOrDeleteBranch", () => {
     expect(result.shouldDeleteBranch).toBe(true);
     expect(result.branchLink).toBe("");
     expect(consoleLogSpy).toHaveBeenCalledWith(
-      "Branch claude/issue-123-20240101_123456 has no commits from Claude, will delete it",
+      "Branch claude/issue-123-20240101-1234 has no commits from Claude, will delete it",
     );
   });
 
@@ -90,14 +90,14 @@ describe("checkAndCommitOrDeleteBranch", () => {
       mockOctokit,
       "owner",
       "repo",
-      "claude/issue-123-20240101_123456",
+      "claude/issue-123-20240101-1234",
       "main",
       false,
     );
 
     expect(result.shouldDeleteBranch).toBe(false);
     expect(result.branchLink).toBe(
-      `\n[View branch](${GITHUB_SERVER_URL}/owner/repo/tree/claude/issue-123-20240101_123456)`,
+      `\n[View branch](${GITHUB_SERVER_URL}/owner/repo/tree/claude/issue-123-20240101-1234)`,
     );
     expect(consoleLogSpy).not.toHaveBeenCalledWith(
       expect.stringContaining("has no commits"),
@@ -123,14 +123,14 @@ describe("checkAndCommitOrDeleteBranch", () => {
       mockOctokit,
       "owner",
       "repo",
-      "claude/issue-123-20240101_123456",
+      "claude/issue-123-20240101-1234",
       "main",
       false,
     );
 
     expect(result.shouldDeleteBranch).toBe(false);
     expect(result.branchLink).toBe(
-      `\n[View branch](${GITHUB_SERVER_URL}/owner/repo/tree/claude/issue-123-20240101_123456)`,
+      `\n[View branch](${GITHUB_SERVER_URL}/owner/repo/tree/claude/issue-123-20240101-1234)`,
     );
     expect(consoleErrorSpy).toHaveBeenCalledWith(
       "Error comparing commits on Claude branch:",
@@ -146,7 +146,7 @@ describe("checkAndCommitOrDeleteBranch", () => {
       mockOctokit,
       "owner",
       "repo",
-      "claude/issue-123-20240101_123456",
+      "claude/issue-123-20240101-1234",
       "main",
       true, // commit signing enabled - will try to delete
     );
@@ -154,7 +154,7 @@ describe("checkAndCommitOrDeleteBranch", () => {
     expect(result.shouldDeleteBranch).toBe(true);
     expect(result.branchLink).toBe("");
     expect(consoleErrorSpy).toHaveBeenCalledWith(
-      "Failed to delete branch claude/issue-123-20240101_123456:",
+      "Failed to delete branch claude/issue-123-20240101-1234:",
       deleteError,
     );
   });
@@ -170,7 +170,7 @@ describe("checkAndCommitOrDeleteBranch", () => {
       mockOctokit,
       "owner",
       "repo",
-      "claude/issue-123-20240101_123456",
+      "claude/issue-123-20240101-1234",
       "main",
       false,
     );
@@ -178,10 +178,10 @@ describe("checkAndCommitOrDeleteBranch", () => {
     expect(result.shouldDeleteBranch).toBe(false);
     expect(result.branchLink).toBe("");
     expect(consoleLogSpy).toHaveBeenCalledWith(
-      "Branch claude/issue-123-20240101_123456 does not exist remotely",
+      "Branch claude/issue-123-20240101-1234 does not exist remotely",
     );
     expect(consoleLogSpy).toHaveBeenCalledWith(
-      "Branch claude/issue-123-20240101_123456 does not exist remotely, no branch link will be added",
+      "Branch claude/issue-123-20240101-1234 does not exist remotely, no branch link will be added",
     );
   });
 });
diff --git a/test/comment-logic.test.ts b/test/comment-logic.test.ts
index 0500c08..f1b3754 100644
--- a/test/comment-logic.test.ts
+++ b/test/comment-logic.test.ts
@@ -103,12 +103,12 @@ describe("updateCommentBody", () => {
     it("adds branch name with link to header when provided", () => {
       const input = {
         ...baseInput,
-        branchName: "claude/issue-123-20240101_120000",
+        branchName: "claude/issue-123-20240101-1200",
       };
 
       const result = updateCommentBody(input);
       expect(result).toContain(
-        "• [`claude/issue-123-20240101_120000`](https://github.com/owner/repo/tree/claude/issue-123-20240101_120000)",
+        "• [`claude/issue-123-20240101-1200`](https://github.com/owner/repo/tree/claude/issue-123-20240101-1200)",
       );
     });
 
@@ -384,9 +384,9 @@ describe("updateCommentBody", () => {
       const input = {
         ...baseInput,
         currentBody: "Claude Code is working… <img src='spinner.gif' />",
-        branchName: "claude/pr-456-20240101_120000",
+        branchName: "claude/pr-456-20240101-1200",
         prLink:
-          "\n[Create a PR](https://github.com/owner/repo/compare/main...claude/pr-456-20240101_120000)",
+          "\n[Create a PR](https://github.com/owner/repo/compare/main...claude/pr-456-20240101-1200)",
         triggerUsername: "jane-doe",
       };
 
@@ -394,7 +394,7 @@ describe("updateCommentBody", () => {
 
       // Should include the PR link in the formatted style
       expect(result).toContain(
-        "• [Create PR ➔](https://github.com/owner/repo/compare/main...claude/pr-456-20240101_120000)",
+        "• [Create PR ➔](https://github.com/owner/repo/compare/main...claude/pr-456-20240101-1200)",
       );
       expect(result).toContain("**Claude finished @jane-doe's task**");
     });
@@ -403,21 +403,21 @@ describe("updateCommentBody", () => {
       const input = {
         ...baseInput,
         currentBody: "Claude Code is working…",
-        branchName: "claude/issue-123-20240101_120000",
+        branchName: "claude/issue-123-20240101-1200",
         branchLink:
-          "\n[View branch](https://github.com/owner/repo/tree/claude/issue-123-20240101_120000)",
+          "\n[View branch](https://github.com/owner/repo/tree/claude/issue-123-20240101-1200)",
         prLink:
-          "\n[Create a PR](https://github.com/owner/repo/compare/main...claude/issue-123-20240101_120000)",
+          "\n[Create a PR](https://github.com/owner/repo/compare/main...claude/issue-123-20240101-1200)",
       };
 
       const result = updateCommentBody(input);
 
       // Should include both links in formatted style
       expect(result).toContain(
-        "• [`claude/issue-123-20240101_120000`](https://github.com/owner/repo/tree/claude/issue-123-20240101_120000)",
+        "• [`claude/issue-123-20240101-1200`](https://github.com/owner/repo/tree/claude/issue-123-20240101-1200)",
       );
       expect(result).toContain(
-        "• [Create PR ➔](https://github.com/owner/repo/compare/main...claude/issue-123-20240101_120000)",
+        "• [Create PR ➔](https://github.com/owner/repo/compare/main...claude/issue-123-20240101-1200)",
       );
     });
 
diff --git a/test/create-prompt.test.ts b/test/create-prompt.test.ts
index 4fd3591..de6c7ba 100644
--- a/test/create-prompt.test.ts
+++ b/test/create-prompt.test.ts
@@ -127,7 +127,7 @@ describe("generatePrompt", () => {
         commentId: "67890",
         isPR: false,
         baseBranch: "main",
-        claudeBranch: "claude/issue-67890-20240101_120000",
+        claudeBranch: "claude/issue-67890-20240101-1200",
         issueNumber: "67890",
         commentBody: "@claude please fix this",
       },
@@ -183,7 +183,7 @@ describe("generatePrompt", () => {
         isPR: false,
         issueNumber: "789",
         baseBranch: "main",
-        claudeBranch: "claude/issue-789-20240101_120000",
+        claudeBranch: "claude/issue-789-20240101-1200",
       },
     };
 
@@ -210,7 +210,7 @@ describe("generatePrompt", () => {
         isPR: false,
         issueNumber: "999",
         baseBranch: "develop",
-        claudeBranch: "claude/issue-999-20240101_120000",
+        claudeBranch: "claude/issue-999-20240101-1200",
         assigneeTrigger: "claude-bot",
       },
     };
@@ -237,7 +237,7 @@ describe("generatePrompt", () => {
         isPR: false,
         issueNumber: "888",
         baseBranch: "main",
-        claudeBranch: "claude/issue-888-20240101_120000",
+        claudeBranch: "claude/issue-888-20240101-1200",
         labelTrigger: "claude-task",
       },
     };
@@ -265,7 +265,7 @@ describe("generatePrompt", () => {
         isPR: false,
         issueNumber: "789",
         baseBranch: "main",
-        claudeBranch: "claude/issue-789-20240101_120000",
+        claudeBranch: "claude/issue-789-20240101-1200",
       },
     };
 
@@ -312,7 +312,7 @@ describe("generatePrompt", () => {
         isPR: false,
         issueNumber: "123",
         baseBranch: "main",
-        claudeBranch: "claude/issue-67890-20240101_120000",
+        claudeBranch: "claude/issue-67890-20240101-1200",
         commentBody: "@claude please fix this",
       },
     };
@@ -334,7 +334,7 @@ describe("generatePrompt", () => {
         isPR: false,
         issueNumber: "123",
         baseBranch: "main",
-        claudeBranch: "claude/issue-67890-20240101_120000",
+        claudeBranch: "claude/issue-67890-20240101-1200",
         commentBody: "@claude please fix this",
       },
     };
@@ -388,7 +388,7 @@ describe("generatePrompt", () => {
         isPR: false,
         issueNumber: "789",
         baseBranch: "main",
-        claudeBranch: "claude/issue-789-20240101_120000",
+        claudeBranch: "claude/issue-789-20240101-1200",
       },
     };
 
@@ -396,10 +396,10 @@ describe("generatePrompt", () => {
 
     // Should contain Issue-specific instructions
     expect(prompt).toContain(
-      "You are already on the correct branch (claude/issue-789-20240101_120000)",
+      "You are already on the correct branch (claude/issue-789-20240101-1200)",
     );
     expect(prompt).toContain(
-      "IMPORTANT: You are already on the correct branch (claude/issue-789-20240101_120000)",
+      "IMPORTANT: You are already on the correct branch (claude/issue-789-20240101-1200)",
     );
     expect(prompt).toContain("Create a PR](https://github.com/");
     expect(prompt).toContain(
@@ -426,7 +426,7 @@ describe("generatePrompt", () => {
         isPR: false,
         issueNumber: "123",
         baseBranch: "main",
-        claudeBranch: "claude/issue-123-20240101_120000",
+        claudeBranch: "claude/issue-123-20240101-1200",
         commentBody: "@claude please fix this",
       },
     };
@@ -435,13 +435,13 @@ describe("generatePrompt", () => {
 
     // Should contain the actual branch name with timestamp
     expect(prompt).toContain(
-      "You are already on the correct branch (claude/issue-123-20240101_120000)",
+      "You are already on the correct branch (claude/issue-123-20240101-1200)",
     );
     expect(prompt).toContain(
-      "IMPORTANT: You are already on the correct branch (claude/issue-123-20240101_120000)",
+      "IMPORTANT: You are already on the correct branch (claude/issue-123-20240101-1200)",
     );
     expect(prompt).toContain(
-      "The branch-name is the current branch: claude/issue-123-20240101_120000",
+      "The branch-name is the current branch: claude/issue-123-20240101-1200",
     );
   });
 
@@ -456,7 +456,7 @@ describe("generatePrompt", () => {
         isPR: true,
         prNumber: "456",
         commentBody: "@claude please fix this",
-        claudeBranch: "claude/pr-456-20240101_120000",
+        claudeBranch: "claude/pr-456-20240101-1200",
         baseBranch: "main",
       },
     };
@@ -465,13 +465,13 @@ describe("generatePrompt", () => {
 
     // Should contain branch-specific instructions like issues
     expect(prompt).toContain(
-      "You are already on the correct branch (claude/pr-456-20240101_120000)",
+      "You are already on the correct branch (claude/pr-456-20240101-1200)",
     );
     expect(prompt).toContain(
       "Create a PR](https://github.com/owner/repo/compare/main",
     );
     expect(prompt).toContain(
-      "The branch-name is the current branch: claude/pr-456-20240101_120000",
+      "The branch-name is the current branch: claude/pr-456-20240101-1200",
     );
     expect(prompt).toContain("Reference to the original PR");
     expect(prompt).toContain(
@@ -525,7 +525,7 @@ describe("generatePrompt", () => {
         isPR: true,
         prNumber: "789",
         commentBody: "@claude please update this",
-        claudeBranch: "claude/pr-789-20240101_123000",
+        claudeBranch: "claude/pr-789-20240101-1230",
         baseBranch: "develop",
       },
     };
@@ -534,7 +534,7 @@ describe("generatePrompt", () => {
 
     // Should contain new branch instructions
     expect(prompt).toContain(
-      "You are already on the correct branch (claude/pr-789-20240101_123000)",
+      "You are already on the correct branch (claude/pr-789-20240101-1230)",
     );
     expect(prompt).toContain(
       "Create a PR](https://github.com/owner/repo/compare/develop",
@@ -553,7 +553,7 @@ describe("generatePrompt", () => {
         prNumber: "999",
         commentId: "review-comment-123",
         commentBody: "@claude fix this issue",
-        claudeBranch: "claude/pr-999-20240101_140000",
+        claudeBranch: "claude/pr-999-20240101-1400",
         baseBranch: "main",
       },
     };
@@ -562,7 +562,7 @@ describe("generatePrompt", () => {
 
     // Should contain new branch instructions
     expect(prompt).toContain(
-      "You are already on the correct branch (claude/pr-999-20240101_140000)",
+      "You are already on the correct branch (claude/pr-999-20240101-1400)",
     );
     expect(prompt).toContain("Create a PR](https://github.com/");
     expect(prompt).toContain("Reference to the original PR");
@@ -581,7 +581,7 @@ describe("generatePrompt", () => {
         eventAction: "closed",
         isPR: true,
         prNumber: "555",
-        claudeBranch: "claude/pr-555-20240101_150000",
+        claudeBranch: "claude/pr-555-20240101-1500",
         baseBranch: "main",
       },
     };
@@ -590,7 +590,7 @@ describe("generatePrompt", () => {
 
     // Should contain new branch instructions
     expect(prompt).toContain(
-      "You are already on the correct branch (claude/pr-555-20240101_150000)",
+      "You are already on the correct branch (claude/pr-555-20240101-1500)",
     );
     expect(prompt).toContain("Create a PR](https://github.com/");
     expect(prompt).toContain("Reference to the original PR");
@@ -683,7 +683,7 @@ describe("getEventTypeAndContext", () => {
         isPR: false,
         issueNumber: "999",
         baseBranch: "main",
-        claudeBranch: "claude/issue-999-20240101_120000",
+        claudeBranch: "claude/issue-999-20240101-1200",
         assigneeTrigger: "claude-bot",
       },
     };
@@ -705,7 +705,7 @@ describe("getEventTypeAndContext", () => {
         isPR: false,
         issueNumber: "888",
         baseBranch: "main",
-        claudeBranch: "claude/issue-888-20240101_120000",
+        claudeBranch: "claude/issue-888-20240101-1200",
         labelTrigger: "claude-task",
       },
     };
@@ -728,7 +728,7 @@ describe("getEventTypeAndContext", () => {
         isPR: false,
         issueNumber: "999",
         baseBranch: "main",
-        claudeBranch: "claude/issue-999-20240101_120000",
+        claudeBranch: "claude/issue-999-20240101-1200",
         // No assigneeTrigger when using directPrompt
       },
     };
diff --git a/test/prepare-context.test.ts b/test/prepare-context.test.ts
index 904dd37..fb2e9d0 100644
--- a/test/prepare-context.test.ts
+++ b/test/prepare-context.test.ts
@@ -35,7 +35,7 @@ describe("parseEnvVarsWithContext", () => {
         process.env = {
           ...BASE_ENV,
           BASE_BRANCH: "main",
-          CLAUDE_BRANCH: "claude/issue-67890-20240101_120000",
+          CLAUDE_BRANCH: "claude/issue-67890-20240101-1200",
         };
       });
 
@@ -44,7 +44,7 @@ describe("parseEnvVarsWithContext", () => {
           mockIssueCommentContext,
           "12345",
           "main",
-          "claude/issue-67890-20240101_120000",
+          "claude/issue-67890-20240101-1200",
         );
 
         expect(result.repository).toBe("test-owner/test-repo");
@@ -60,7 +60,7 @@ describe("parseEnvVarsWithContext", () => {
           expect(result.eventData.issueNumber).toBe("55");
           expect(result.eventData.commentId).toBe("12345678");
           expect(result.eventData.claudeBranch).toBe(
-            "claude/issue-67890-20240101_120000",
+            "claude/issue-67890-20240101-1200",
           );
           expect(result.eventData.baseBranch).toBe("main");
           expect(result.eventData.commentBody).toBe(
@@ -81,7 +81,7 @@ describe("parseEnvVarsWithContext", () => {
             mockIssueCommentContext,
             "12345",
             undefined,
-            "claude/issue-67890-20240101_120000",
+            "claude/issue-67890-20240101-1200",
           ),
         ).toThrow("BASE_BRANCH is required for issue_comment event");
       });
@@ -152,7 +152,7 @@ describe("parseEnvVarsWithContext", () => {
       process.env = {
         ...BASE_ENV,
         BASE_BRANCH: "main",
-        CLAUDE_BRANCH: "claude/issue-42-20240101_120000",
+        CLAUDE_BRANCH: "claude/issue-42-20240101-1200",
       };
     });
 
@@ -161,7 +161,7 @@ describe("parseEnvVarsWithContext", () => {
         mockIssueOpenedContext,
         "12345",
         "main",
-        "claude/issue-42-20240101_120000",
+        "claude/issue-42-20240101-1200",
       );
 
       expect(result.eventData.eventName).toBe("issues");
@@ -174,7 +174,7 @@ describe("parseEnvVarsWithContext", () => {
         expect(result.eventData.issueNumber).toBe("42");
         expect(result.eventData.baseBranch).toBe("main");
         expect(result.eventData.claudeBranch).toBe(
-          "claude/issue-42-20240101_120000",
+          "claude/issue-42-20240101-1200",
         );
       }
     });
@@ -184,7 +184,7 @@ describe("parseEnvVarsWithContext", () => {
         mockIssueAssignedContext,
         "12345",
         "main",
-        "claude/issue-123-20240101_120000",
+        "claude/issue-123-20240101-1200",
       );
 
       expect(result.eventData.eventName).toBe("issues");
@@ -197,7 +197,7 @@ describe("parseEnvVarsWithContext", () => {
         expect(result.eventData.issueNumber).toBe("123");
         expect(result.eventData.baseBranch).toBe("main");
         expect(result.eventData.claudeBranch).toBe(
-          "claude/issue-123-20240101_120000",
+          "claude/issue-123-20240101-1200",
         );
         expect(result.eventData.assigneeTrigger).toBe("@claude-bot");
       }
@@ -215,7 +215,7 @@ describe("parseEnvVarsWithContext", () => {
           mockIssueOpenedContext,
           "12345",
           undefined,
-          "claude/issue-42-20240101_120000",
+          "claude/issue-42-20240101-1200",
         ),
       ).toThrow("BASE_BRANCH is required for issues event");
     });
@@ -234,7 +234,7 @@ describe("parseEnvVarsWithContext", () => {
         contextWithDirectPrompt,
         "12345",
         "main",
-        "claude/issue-123-20240101_120000",
+        "claude/issue-123-20240101-1200",
       );
 
       expect(result.eventData.eventName).toBe("issues");
@@ -264,7 +264,7 @@ describe("parseEnvVarsWithContext", () => {
           contextWithoutTriggers,
           "12345",
           "main",
-          "claude/issue-123-20240101_120000",
+          "claude/issue-123-20240101-1200",
         ),
       ).toThrow("ASSIGNEE_TRIGGER is required for issue assigned event");
     });