diff --git a/src/agents/tools/tts-tool.ts b/src/agents/tools/tts-tool.ts
index e7933cfa0cc..349fdb0915b 100644
--- a/src/agents/tools/tts-tool.ts
+++ b/src/agents/tools/tts-tool.ts
@@ -29,7 +29,7 @@ export function createTtsTool(opts?: {
       const channel = readStringParam(params, "channel");
       const resolvedChannel = channel ?? opts?.agentChannel;
 
-      if (!resolvedChannel) {
+      if (!opts?.agentChannel && !channel) {
         return {
           content: [
             {