init
diff --git a/tools/func.go b/tools/func.go
new file mode 100644
index 0000000..9ad2add
--- /dev/null
+++ b/tools/func.go
@@ -0,0 +1,66 @@
+package tools
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/invopop/jsonschema"
+)
+
+type FuncTool[I any, O any] struct {
+	name   string
+	desc   string
+	schema *jsonschema.Schema
+	fn     func(args I) (O, error)
+}
+
+func NewFuncTool[I any, O any](name string, fn func(args I) (O, error), desc string) *FuncTool[I, O] {
+	return &FuncTool[I, O]{
+		name,
+		fmt.Sprintf("%s\nResult schema: %s", desc, GenerateSchema[O]()),
+		GenerateSchema[I](),
+		fn,
+	}
+}
+
+func (ft *FuncTool[I, O]) Name() string {
+	return ft.name
+}
+
+func (ft *FuncTool[I, O]) Description() string {
+	return ft.desc
+}
+
+func (ft *FuncTool[I, O]) InputSchema() *jsonschema.Schema {
+	return ft.schema
+}
+
+func (ft *FuncTool[I, O]) Call(inp string) (string, error) {
+	var args I
+	if err := json.NewDecoder(strings.NewReader(inp)).Decode(&args); err != nil {
+		return "", err
+	}
+	out, err := ft.fn(args)
+	if err != nil {
+		return "", err
+	}
+	var resp strings.Builder
+	if err := json.NewEncoder(&resp).Encode(out); err != nil {
+		return "", err
+	}
+	ret := resp.String()
+	fmt.Printf("$$$ %s\n", ret)
+	return ret, nil
+
+}
+
+func GenerateSchema[T any]() *jsonschema.Schema {
+	reflector := jsonschema.Reflector{
+		AllowAdditionalProperties:  false,
+		RequiredFromJSONSchemaTags: true,
+		DoNotReference:             true,
+	}
+	var v T
+	return reflector.Reflect(v)
+}