diff --git a/src/agent/modify.ts b/src/agent/modify.ts
index b22e64d..75bef83 100644
--- a/src/agent/modify.ts
+++ b/src/agent/modify.ts
@@ -30,6 +30,7 @@ function buildModelSettings(
   const isAnthropic =
     modelHandle.startsWith("anthropic/") ||
     modelHandle.startsWith(`${ANTHROPIC_PROVIDER_NAME}/`);
+  const isZai = modelHandle.startsWith("zai/");
   const isGoogleAI = modelHandle.startsWith("google_ai/");
   const isGoogleVertex = modelHandle.startsWith("google_vertex/");
   const isOpenRouter = modelHandle.startsWith("openrouter/");
@@ -70,6 +71,13 @@ function buildModelSettings(
       };
     }
     settings = anthropicSettings;
+  } else if (isZai) {
+    // Zai uses the same model_settings structure as other providers.
+    // Ensure parallel_tool_calls is enabled.
+    settings = {
+      provider_type: "zai",
+      parallel_tool_calls: true,
+    };
   } else if (isGoogleAI) {
     const googleSettings: GoogleAIModelSettings & { temperature?: number } = {
       provider_type: "google_ai",