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

context.go

@@ -7,9 +7,10 @@ import (
 
 type Context struct {
 	context.Context
-	request  Request
-	response *ResponseChoice
-	toolcall *ToolCall
+	request         Request
+	response        *ResponseChoice
+	toolcall        *ToolCall
+	syntheticFields map[string]string
 }
 
 func (c *Context) ToNewRequest(toolResults ...ToolCallResponse) Request {
@@ -55,20 +56,32 @@ func (c *Context) ToolCall() *ToolCall {
 	return c.toolcall
 }
 
+func (c *Context) SyntheticFields() map[string]string {
+	if c.syntheticFields == nil {
+		c.syntheticFields = map[string]string{}
+	}
+
+	return c.syntheticFields
+}
+
 func (c *Context) WithContext(ctx context.Context) *Context {
-	return &Context{Context: ctx, request: c.request, response: c.response, toolcall: c.toolcall}
+	return &Context{Context: ctx, request: c.request, response: c.response, toolcall: c.toolcall, syntheticFields: c.syntheticFields}
 }
 
 func (c *Context) WithRequest(request Request) *Context {
-	return &Context{Context: c.Context, request: request, response: c.response, toolcall: c.toolcall}
+	return &Context{Context: c.Context, request: request, response: c.response, toolcall: c.toolcall, syntheticFields: c.syntheticFields}
 }
 
 func (c *Context) WithResponse(response *ResponseChoice) *Context {
-	return &Context{Context: c.Context, request: c.request, response: response, toolcall: c.toolcall}
+	return &Context{Context: c.Context, request: c.request, response: response, toolcall: c.toolcall, syntheticFields: c.syntheticFields}
 }
 
 func (c *Context) WithToolCall(toolcall *ToolCall) *Context {
-	return &Context{Context: c.Context, request: c.request, response: c.response, toolcall: toolcall}
+	return &Context{Context: c.Context, request: c.request, response: c.response, toolcall: toolcall, syntheticFields: c.syntheticFields}
+}
+
+func (c *Context) WithSyntheticFields(syntheticFields map[string]string) *Context {
+	return &Context{Context: c.Context, request: c.request, response: c.response, toolcall: c.toolcall, syntheticFields: syntheticFields}
 }
 
 func (c *Context) Deadline() (deadline time.Time, ok bool) {
@@ -84,8 +97,19 @@ func (c *Context) Err() error {
 }
 
 func (c *Context) Value(key any) any {
-	if key == "request" {
+	switch key {
+	case "request":
 		return c.request
+
+	case "response":
+		return c.response
+
+	case "toolcall":
+		return c.toolcall
+
+	case "syntheticFields":
+		return c.syntheticFields
+
 	}
 	return c.Context.Value(key)
 }