diff --git a/dist/index.d.ts b/dist/index.d.ts
index 1b8df0289811d82777e853bc4290e35b16b0bd36..4682f7bbf62b1bc3d65abde34d7366c64f9b5eb0 100644
--- a/dist/index.d.ts
+++ b/dist/index.d.ts
@@ -96,6 +96,8 @@ interface CompletionToolCall {
 }
 interface CompletionToolResult {
     args: Record<string, unknown>;
+    error?: Error;
+    isError?: boolean;
     result: ToolMessage['content'];
     toolCallId: string;
     toolName: string;
@@ -222,9 +224,32 @@ interface DetermineStepTypeOptions {
 /** @internal */
 declare const determineStepType: ({ finishReason, stepsLength, toolCallsLength, willContinue }: DetermineStepTypeOptions) => CompletionStepType;
 
+type OnToolCallFinishCallback = (context: {
+    durationMs: number;
+    error?: unknown;
+    output?: unknown;
+    toolCallId: string;
+    toolName: string;
+}) => Promise<void> | void;
+type OnToolCallStartCallback = (context: {
+    input: unknown;
+    toolCallId: string;
+    toolName: string;
+}) => Promise<void> | void;
+type RepairToolCallFunction = (context: {
+    error: Error;
+    messages: Message[];
+    toolCall: ToolCall;
+    tools?: Tool[];
+}) => Promise<ToolCall | null> | ToolCall | null;
+
 interface ExecuteToolOptions {
     abortSignal?: AbortSignal;
+    captureToolErrors?: boolean;
     messages: Message[];
+    onToolCallFinish?: OnToolCallFinishCallback;
+    onToolCallStart?: OnToolCallStartCallback;
+    repairToolCall?: RepairToolCallFunction;
     toolCall: ToolCall;
     tools?: Tool[];
 }
@@ -233,7 +257,7 @@ interface ExecuteToolResult {
     completionToolResult: CompletionToolResult;
     message: ToolMessage;
 }
-declare const executeTool: ({ abortSignal, messages, toolCall, tools }: ExecuteToolOptions) => Promise<ExecuteToolResult>;
+declare const executeTool: (options: ExecuteToolOptions) => Promise<ExecuteToolResult>;
 
 interface ResolvedStepOptions {
     messages: Message[];
@@ -256,4 +280,4 @@ declare const hasToolCall: (name?: string) => StopCondition;
 declare const shouldStop: (stopWhen: StopCondition, context: StopContext) => boolean;
 
 export { and, chat, determineStepType, executeTool, hasToolCall, not, or, resolveStepOptions, shouldStop, stepCountAtLeast };
-export type { AssistantMessage, AudioContentPart, ChatOptions, CommonContentPart, CompletionStep, CompletionStepType, CompletionToolCall, CompletionToolResult, DetermineStepTypeOptions, DeveloperMessage, ExecuteToolOptions, ExecuteToolResult, FileContentPart, FinishReason, ImageContentPart, Message, PrepareStep, PrepareStepOptions, PrepareStepResult, RefusalContentPart, ResolveStepOptionsOptions, ResolvedStepOptions, StopCondition, StopContext, StopStep, SystemMessage, TextContentPart, Tool, ToolCall, ToolChoice, ToolExecuteOptions, ToolExecuteResult, ToolMessage, Usage, UserMessage };
+export type { AssistantMessage, AudioContentPart, ChatOptions, CommonContentPart, CompletionStep, CompletionStepType, CompletionToolCall, CompletionToolResult, DetermineStepTypeOptions, DeveloperMessage, ExecuteToolOptions, ExecuteToolResult, FileContentPart, FinishReason, ImageContentPart, Message, OnToolCallFinishCallback, OnToolCallStartCallback, PrepareStep, PrepareStepOptions, PrepareStepResult, RefusalContentPart, RepairToolCallFunction, ResolveStepOptionsOptions, ResolvedStepOptions, StopCondition, StopContext, StopStep, SystemMessage, TextContentPart, Tool, ToolCall, ToolChoice, ToolExecuteOptions, ToolExecuteResult, ToolMessage, Usage, UserMessage };
diff --git a/dist/index.js b/dist/index.js
index 34e87341ac400dd8c61457c188485b82a1383300..2e7e1fa99fdbccb7a0be0af92504ed903d95c482 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -66,57 +66,150 @@ const runTool = async (tool, options) => {
     });
   }
 };
-const executeTool = async ({ abortSignal, messages, toolCall, tools }) => {
-  const toolName = toolCall.function.name;
-  const toolArguments = toolCall.function.arguments;
-  if (toolName == null) {
-    throw new InvalidToolCallError(`Missing toolCall.function.name: ${JSON.stringify(toolCall)}`, {
-      reason: "missing_name",
-      toolCall
-    });
-  }
-  if (toolArguments == null) {
-    throw new InvalidToolCallError(`Missing toolCall.function.arguments: ${JSON.stringify(toolCall)}`, {
-      reason: "missing_arguments",
-      toolCall
-    });
-  }
-  const tool = tools?.find((tool2) => tool2.function.name === toolName);
-  if (!tool) {
-    const availableTools = tools?.map((tool2) => tool2.function.name);
-    const availableToolsErrorMsg = availableTools == null || availableTools.length === 0 ? "No tools are available" : `Available tools: ${availableTools.join(", ")}`;
-    throw new InvalidToolCallError(`Model tried to call unavailable tool "${toolName}", ${availableToolsErrorMsg}.`, {
-      availableTools,
-      reason: "unknown_tool",
-      toolCall,
-      toolName
-    });
-  }
-  const parsedArgs = parseToolInput(toolName, toolArguments);
-  const result = await runTool(tool, { abortSignal, messages, parsedArgs, toolCall });
-  const completionToolCall = {
-    args: toolArguments,
-    toolCallId: toolCall.id,
-    toolCallType: toolCall.type,
-    toolName
-  };
-  const completionToolResult = {
-    args: parsedArgs,
-    result,
-    toolCallId: toolCall.id,
-    toolName
-  };
-  const message = {
-    content: result,
-    role: "tool",
-    tool_call_id: toolCall.id
-  };
+const buildErrorReturn = (toolCall, toolName, toolCallId, error) => {
+  const errorMessage = error instanceof Error ? error.message : String(error);
+  const errorContent = `Tool call error for "${toolName}": ${errorMessage}`;
   return {
-    completionToolCall,
-    completionToolResult,
-    message
+    completionToolCall: {
+      args: toolCall.function?.arguments ?? "{}",
+      toolCallId,
+      toolCallType: toolCall.type ?? "function",
+      toolName
+    },
+    completionToolResult: {
+      args: {},
+      error,
+      isError: true,
+      result: errorContent,
+      toolCallId,
+      toolName
+    },
+    message: {
+      content: errorContent,
+      role: "tool",
+      tool_call_id: toolCallId
+    }
   };
 };
+const executeTool = async ({
+  abortSignal,
+  captureToolErrors,
+  messages,
+  onToolCallFinish,
+  onToolCallStart,
+  repairToolCall,
+  toolCall,
+  tools
+}) => {
+  const resolvedToolName = toolCall.function?.name ?? "unknown";
+  const toolCallId = toolCall.id;
+  const startTime = Date.now();
+  try {
+    const toolName = toolCall.function.name;
+    const toolArguments = toolCall.function.arguments;
+    if (toolName == null) {
+      throw new InvalidToolCallError(`Missing toolCall.function.name: ${JSON.stringify(toolCall)}`, {
+        reason: "missing_name",
+        toolCall
+      });
+    }
+    if (toolArguments == null) {
+      throw new InvalidToolCallError(`Missing toolCall.function.arguments: ${JSON.stringify(toolCall)}`, {
+        reason: "missing_arguments",
+        toolCall
+      });
+    }
+    const tool = tools?.find((tool2) => tool2.function.name === toolName);
+    if (!tool) {
+      const availableTools = tools?.map((tool2) => tool2.function.name);
+      const availableToolsErrorMsg = availableTools == null || availableTools.length === 0 ? "No tools are available" : `Available tools: ${availableTools.join(", ")}`;
+      throw new InvalidToolCallError(`Model tried to call unavailable tool "${toolName}", ${availableToolsErrorMsg}.`, {
+        availableTools,
+        reason: "unknown_tool",
+        toolCall,
+        toolName
+      });
+    }
+    const parsedArgs = parseToolInput(toolName, toolArguments);
+    if (onToolCallStart) {
+      try {
+        await onToolCallStart({ input: parsedArgs, toolCallId, toolName });
+      } catch {
+      }
+    }
+    const result = await runTool(tool, { abortSignal, messages, parsedArgs, toolCall });
+    if (onToolCallFinish) {
+      try {
+        await onToolCallFinish({
+          durationMs: Date.now() - startTime,
+          error: void 0,
+          output: result,
+          toolCallId,
+          toolName
+        });
+      } catch {
+      }
+    }
+    const completionToolCall = {
+      args: toolArguments,
+      toolCallId: toolCall.id,
+      toolCallType: toolCall.type,
+      toolName
+    };
+    const completionToolResult = {
+      args: parsedArgs,
+      result,
+      toolCallId: toolCall.id,
+      toolName
+    };
+    const message = {
+      content: result,
+      role: "tool",
+      tool_call_id: toolCall.id
+    };
+    return {
+      completionToolCall,
+      completionToolResult,
+      message
+    };
+  } catch (error) {
+    if (isAbortError(error, abortSignal))
+      throw error;
+    if (repairToolCall && (InvalidToolCallError.isInstance(error) || InvalidToolInputError.isInstance(error))) {
+      try {
+        const repaired = await repairToolCall({ error, messages, toolCall, tools });
+        if (repaired != null) {
+          return executeTool({
+            abortSignal,
+            captureToolErrors,
+            messages,
+            onToolCallFinish,
+            onToolCallStart,
+            repairToolCall: void 0,
+            toolCall: repaired,
+            tools
+          });
+        }
+      } catch {
+      }
+    }
+    if (onToolCallFinish) {
+      try {
+        await onToolCallFinish({
+          durationMs: Date.now() - startTime,
+          error,
+          output: void 0,
+          toolCallId,
+          toolName: resolvedToolName
+        });
+      } catch {
+      }
+    }
+    if (!captureToolErrors)
+      throw error;
+    return buildErrorReturn(toolCall, resolvedToolName, toolCallId, error);
+  }
+};
 
 const resolveStepOptions = async ({ messages, model, prepareStep, stepNumber, steps, toolChoice }) => {
   const prepared = prepareStep == null ? void 0 : await prepareStep({