diff --git a/packages/react/src/runtimes/edge/streams/toolResultStream.ts b/packages/react/src/runtimes/edge/streams/toolResultStream.ts
index 0644e343a..8d3757044 100644
--- a/packages/react/src/runtimes/edge/streams/toolResultStream.ts
+++ b/packages/react/src/runtimes/edge/streams/toolResultStream.ts
@@ -27,7 +27,7 @@ export function toolResultStream(tools: Record<string, Tool> | undefined) {
         case "tool-call": {
           const { toolCallId, toolCallType, toolName, args: argsText } = chunk;
           const tool = tools?.[toolName];
-          if (!tool) return;
+          if (!tool || !tool.execute) return;
 
           const args = sjson.parse(argsText);
           if (tool.parameters instanceof z.ZodType) {
@@ -43,7 +43,7 @@ export function toolResultStream(tools: Record<string, Tool> | undefined) {
                 toolCallId,
                 (async () => {
                   try {
-                    const result = await tool.execute(args);
+                    const result = await tool.execute!(args);
 
                     controller.enqueue({
                       type: "tool-result",
diff --git a/packages/react/src/types/ModelConfigTypes.ts b/packages/react/src/types/ModelConfigTypes.ts
index 7c5666176..047a47834 100644
--- a/packages/react/src/types/ModelConfigTypes.ts
+++ b/packages/react/src/types/ModelConfigTypes.ts
@@ -8,7 +8,7 @@ type ToolExecuteFunction<TArgs, TResult> = (
 export type Tool<TArgs = unknown, TResult = unknown> = {
   description?: string | undefined;
   parameters: z.ZodSchema<TArgs> | JSONSchema7;
-  execute: ToolExecuteFunction<TArgs, TResult>;
+  execute?: ToolExecuteFunction<TArgs, TResult>;
 };
 
 export type ModelConfig = {
diff --git a/packages/react/src/types/index.ts b/packages/react/src/types/index.ts
index 338c3ac58..850eff0ad 100644
--- a/packages/react/src/types/index.ts
+++ b/packages/react/src/types/index.ts
@@ -34,6 +34,10 @@ export type {
   ToolCallContentPartComponent,
 } from "./ContentPartComponentTypes";
 
-export type { ModelConfig, ModelConfigProvider } from "./ModelConfigTypes";
+export type {
+  ModelConfig,
+  ModelConfigProvider,
+  Tool,
+} from "./ModelConfigTypes";
 
 export type { Unsubscribe } from "./Unsubscribe";