diff --git a/src/github/operations/branch.ts b/src/github/operations/branch.ts
index 870cd649..920eec56 100644
--- a/src/github/operations/branch.ts
+++ b/src/github/operations/branch.ts
@@ -58,16 +58,18 @@ export function validateBranchName(branchName: string): void {
     );
   }
 
-  // Strict whitelist pattern: alphanumeric start, then alphanumeric/slash/hyphen/underscore/period/hash/plus.
+  // Strict whitelist pattern: alphanumeric start, then alphanumeric/slash/hyphen/underscore/period/hash/plus/comma.
   // # is valid per git-check-ref-format and commonly used in branch names like "fix/#123-description".
   // + is valid per git-check-ref-format and generated by Claude Code's EnterWorktree tool when
   //   converting worktree names containing "/" (e.g. "feat/foo" becomes "worktree-feat+foo").
-  // All git calls use execFileSync (not shell interpolation), so neither # nor + carries injection risk.
-  const validPattern = /^[a-zA-Z0-9][a-zA-Z0-9/_.#+-]*$/;
+  // , is valid per git-check-ref-format and commonly appears in branch names derived from titles
+  //   or external identifiers (e.g. place names like "feature/paris,france").
+  // All git calls use execFileSync (not shell interpolation), so none of these characters carry injection risk.
+  const validPattern = /^[a-zA-Z0-9][a-zA-Z0-9/_.#+,-]*$/;
 
   if (!validPattern.test(branchName)) {
     throw new Error(
-      `Invalid branch name: "${branchName}". Branch names must start with an alphanumeric character and contain only alphanumeric characters, forward slashes, hyphens, underscores, periods, hashes (#), or plus signs (+).`,
+      `Invalid branch name: "${branchName}". Branch names must start with an alphanumeric character and contain only alphanumeric characters, forward slashes, hyphens, underscores, periods, hashes (#), plus signs (+), or commas (,).`,
     );
   }
 
diff --git a/test/validate-branch-name.test.ts b/test/validate-branch-name.test.ts
index 9594b48d..5a9bf680 100644
--- a/test/validate-branch-name.test.ts
+++ b/test/validate-branch-name.test.ts
@@ -55,6 +55,15 @@ describe("validateBranchName", () => {
       expect(() => validateBranchName("fix+issue-123")).not.toThrow();
       expect(() => validateBranchName("feature+new-thing")).not.toThrow();
     });
+
+    it("should accept branch names containing , (git-valid, common in title-derived branches)", () => {
+      // Reported in #1300: branches like "feature/a,b" were rejected, even though
+      // git check-ref-format and GitHub both accept commas. Common when branch names
+      // are derived from titles, place names, or external identifiers.
+      expect(() => validateBranchName("feature/a,b")).not.toThrow();
+      expect(() => validateBranchName("feature/paris,france")).not.toThrow();
+      expect(() => validateBranchName("fix/issue-1,2,3")).not.toThrow();
+    });
   });
 
   describe("command injection attempts", () => {