Refactor toolbox and function handling to support synthetic fields and improve type definitions

schema/object.go

@@ -8,15 +8,44 @@ import (
 	"github.com/openai/openai-go"
 )
 
-type object struct {
+const (
+	// SyntheticFieldPrefix is any prefix that is added to any synthetic fields that are added to the object, to prevent
+	// collisions with the fields in the struct.
+	SyntheticFieldPrefix = "__"
+)
+
+type Object struct {
 	basic
 
 	ref reflect.Type
 
 	fields map[string]Type
+
+	// syntheticFields are fields that are not in the struct but are generated by a system.
+	synetheticFields map[string]Type
 }
 
-func (o object) OpenAIParameters() openai.FunctionParameters {
+func (o Object) WithSyntheticField(name string, description string) Object {
+	if o.synetheticFields == nil {
+		o.synetheticFields = map[string]Type{}
+	}
+
+	o.synetheticFields[name] = basic{
+		DataType:    TypeString,
+		typeName:    "string",
+		index:       -1,
+		required:    false,
+		description: description,
+	}
+
+	return o
+}
+
+func (o Object) SyntheticFields() map[string]Type {
+	return o.synetheticFields
+}
+
+func (o Object) OpenAIParameters() openai.FunctionParameters {
 	var properties = map[string]openai.FunctionParameters{}
 	var required []string
 	for k, v := range o.fields {
@@ -26,6 +55,13 @@ func (o object) OpenAIParameters() openai.FunctionParameters {
 		}
 	}
 
+	for k, v := range o.synetheticFields {
+		properties[SyntheticFieldPrefix+k] = v.OpenAIParameters()
+		if v.Required() {
+			required = append(required, SyntheticFieldPrefix+k)
+		}
+	}
+
 	var res = openai.FunctionParameters{
 		"type":        "object",
 		"description": o.Description(),
@@ -39,7 +75,7 @@ func (o object) OpenAIParameters() openai.FunctionParameters {
 	return res
 }
 
-func (o object) GoogleParameters() *genai.Schema {
+func (o Object) GoogleParameters() *genai.Schema {
 	var properties = map[string]*genai.Schema{}
 	var required []string
 	for k, v := range o.fields {
@@ -62,7 +98,8 @@ func (o object) GoogleParameters() *genai.Schema {
 	return res
 }
 
-func (o object) FromAny(val any) (reflect.Value, error) {
+// FromAny converts the value from any to the correct type, returning the value, and an error if any
+func (o Object) FromAny(val any) (reflect.Value, error) {
 	// if the value is nil, we can't do anything
 	if val == nil {
 		return reflect.Value{}, nil
@@ -99,7 +136,7 @@ func (o object) FromAny(val any) (reflect.Value, error) {
 	return obj, nil
 }
 
-func (o object) SetValueOnField(obj reflect.Value, val reflect.Value) {
+func (o Object) SetValueOnField(obj reflect.Value, val reflect.Value) {
 	// if this basic type is not required that means it's a pointer type so we need to set the value to the address of the value
 	if !o.required {
 		val = val.Addr()