chore: initial import of standalone agentscope project

src/agentscope/model/_model_usage.py

@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+"""The model usage class in agentscope."""
+from dataclasses import dataclass, field
+from typing import Literal, Any
+
+from .._utils._mixin import DictMixin
+
+
+@dataclass
+class ChatUsage(DictMixin):
+    """The usage of a chat model API invocation."""
+
+    input_tokens: int
+    """The number of input tokens."""
+
+    output_tokens: int
+    """The number of output tokens."""
+
+    time: float
+    """The time used in seconds."""
+
+    type: Literal["chat"] = field(default_factory=lambda: "chat")
+    """The type of the usage, must be `chat`."""
+
+    metadata: dict[str, Any] | None = field(default_factory=lambda: None)
+    """The metadata of the usage."""