diff --git a/function.go b/function.go
index 18c28cb..b5ac2b4 100644
--- a/function.go
+++ b/function.go
@@ -4,11 +4,13 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"gitea.stevedudenhoeffer.com/steve/go-llm/schema"
-	"github.com/sashabaranov/go-openai"
-	"github.com/sashabaranov/go-openai/jsonschema"
 	"reflect"
 	"time"
+
+	"github.com/sashabaranov/go-openai"
+	"github.com/sashabaranov/go-openai/jsonschema"
+
+	"gitea.stevedudenhoeffer.com/steve/go-llm/schema"
 )
 
 type Function struct {
@@ -31,7 +33,7 @@ type Function struct {
 	definition *jsonschema.Definition
 }
 
-func (f *Function) Execute(ctx *Context, input string) (string, error) {
+func (f *Function) Execute(ctx *Context, input string) (any, error) {
 	if !f.fn.IsValid() {
 		return "", fmt.Errorf("function %s is not implemented", f.Name)
 	}
@@ -46,7 +48,7 @@ func (f *Function) Execute(ctx *Context, input string) (string, error) {
 	}
 
 	// now we can call the function
-	exec := func(ctx *Context) (string, error) {
+	exec := func(ctx *Context) (any, error) {
 		out := f.fn.Call([]reflect.Value{reflect.ValueOf(ctx), p.Elem()})
 
 		if len(out) != 2 {
@@ -54,7 +56,7 @@ func (f *Function) Execute(ctx *Context, input string) (string, error) {
 		}
 
 		if out[1].IsNil() {
-			return out[0].String(), nil
+			return out[0].Interface(), nil
 		}
 
 		return "", out[1].Interface().(error)
diff --git a/functions.go b/functions.go
index a28b4da..e1b7ccc 100644
--- a/functions.go
+++ b/functions.go
@@ -1,8 +1,9 @@
 package go_llm
 
 import (
-	"gitea.stevedudenhoeffer.com/steve/go-llm/schema"
 	"reflect"
+
+	"gitea.stevedudenhoeffer.com/steve/go-llm/schema"
 )
 
 // Parse takes a function pointer and returns a function object.
@@ -12,7 +13,7 @@ import (
 // The struct parameters can have the following tags:
 // - Description: a string that describes the parameter, passed to openaiImpl to tell it what the parameter is for
 
-func NewFunction[T any](name string, description string, fn func(*Context, T) (string, error)) *Function {
+func NewFunction[T any](name string, description string, fn func(*Context, T) (any, error)) *Function {
 	var o T
 
 	res := Function{
diff --git a/llm.go b/llm.go
index 058a479..3b19f24 100644
--- a/llm.go
+++ b/llm.go
@@ -2,6 +2,7 @@ package go_llm
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/sashabaranov/go-openai"
 )
@@ -142,7 +143,7 @@ func (t ToolCall) toChatCompletionMessages() []openai.ChatCompletionMessage {
 
 type ToolCallResponse struct {
 	ID     string
-	Result string
+	Result any
 	Error  error
 }
 
@@ -167,7 +168,7 @@ func (t ToolCallResponse) toChatCompletionMessages() []openai.ChatCompletionMess
 
 	if refusal != "" {
 		if t.Result != "" {
-			t.Result = t.Result + " (error in execution: " + refusal + ")"
+			t.Result = fmt.Sprint(t.Result) + " (error in execution: " + refusal + ")"
 		} else {
 			t.Result = "error in execution:" + refusal
 		}
@@ -175,7 +176,7 @@ func (t ToolCallResponse) toChatCompletionMessages() []openai.ChatCompletionMess
 
 	return []openai.ChatCompletionMessage{{
 		Role:       openai.ChatMessageRoleTool,
-		Content:    t.Result,
+		Content:    fmt.Sprint(t.Result),
 		ToolCallID: t.ID,
 	}}
 }
diff --git a/toolbox.go b/toolbox.go
index e4af6e7..61fb44e 100644
--- a/toolbox.go
+++ b/toolbox.go
@@ -87,7 +87,7 @@ var (
 	ErrFunctionNotFound = errors.New("function not found")
 )
 
-func (t *ToolBox) executeFunction(ctx *Context, functionName string, params string) (string, error) {
+func (t *ToolBox) executeFunction(ctx *Context, functionName string, params string) (any, error) {
 	f, ok := t.names[functionName]
 
 	if !ok {
@@ -97,14 +97,14 @@ func (t *ToolBox) executeFunction(ctx *Context, functionName string, params stri
 	return f.Execute(ctx, params)
 }
 
-func (t *ToolBox) Execute(ctx *Context, toolCall ToolCall) (string, error) {
+func (t *ToolBox) Execute(ctx *Context, toolCall ToolCall) (any, error) {
 	return t.executeFunction(ctx.WithToolCall(&toolCall), toolCall.FunctionCall.Name, toolCall.FunctionCall.Arguments)
 }
 
 // ExecuteCallbacks will execute all the tool calls in the given list, and call the given callbacks when a new function is created, and when a function is finished.
 // OnNewFunction is called when a new function is created
 // OnFunctionFinished is called when a function is finished
-func (t *ToolBox) ExecuteCallbacks(ctx *Context, toolCalls []ToolCall, OnNewFunction func(ctx context.Context, funcName string, parameter string) (any, error), OnFunctionFinished func(ctx context.Context, funcName string, parameter string, result string, err error, newFunctionResult any) error) ([]ToolCallResponse, error) {
+func (t *ToolBox) ExecuteCallbacks(ctx *Context, toolCalls []ToolCall, OnNewFunction func(ctx context.Context, funcName string, parameter string) (any, error), OnFunctionFinished func(ctx context.Context, funcName string, parameter string, result any, err error, newFunctionResult any) error) ([]ToolCallResponse, error) {
 	var res []ToolCallResponse
 
 	for _, call := range toolCalls {