refactor: streamline AutoTrajectoryContext management

- Updated the context manager to return the trajectory directly upon entering, simplifying the capture_auto_trajectory function.
- Ensured the trajectory is properly finished upon exiting the context, improving resource management.

Author: bradhilton

src/art/auto_trajectory.py

@@ -62,10 +62,8 @@ def auto_trajectory(*, required: bool = False) -> Trajectory | None:
 
 
 async def capture_auto_trajectory(coroutine: Coroutine[Any, Any, Any]) -> Trajectory:
-    with AutoTrajectoryContext():
+    with AutoTrajectoryContext() as trajectory:
         await coroutine
-        trajectory = auto_trajectory_context_var.get().trajectory
-        trajectory.finish()
         return trajectory
 
 
@@ -76,11 +74,13 @@ def __init__(self) -> None:
             reward=0.0,
         )
 
-    def __enter__(self) -> None:
+    def __enter__(self) -> Trajectory:
         self.token = auto_trajectory_context_var.set(self)
+        return self.trajectory
 
     def __exit__(self, exc_type: Any, exc_value: Any, traceback: Any) -> None:
         auto_trajectory_context_var.reset(self.token)
+        self.trajectory.finish()
 
     def handle_httpx_response(self, response: httpx._models.Response) -> None:
         # Get buffered content (set by patched aiter_bytes/iter_bytes)

src/art/trajectories.py

@@ -1,20 +1,21 @@
 import asyncio
-from contextlib import asynccontextmanager
-from datetime import datetime
 import time
 import traceback
+from contextlib import asynccontextmanager
+from datetime import datetime
 from typing import (
     Any,
     AsyncGenerator,
     Awaitable,
+    Coroutine,
     Iterable,
     Iterator,
     cast,
     overload,
 )
 
-from openai.types.chat.chat_completion import Choice
 import pydantic
+from openai.types.chat.chat_completion import Choice
 
 from .types import Messages, MessagesAndChoices, Tools
 
@@ -262,7 +263,7 @@ def __new__(
         metadata: dict[str, MetadataValue] | None = None,
         metrics: dict[str, float | int | bool] | None = None,
         logs: list[str] | None = None,
-    ) -> "TrajectoryGroup | Awaitable[TrajectoryGroup]":
+    ) -> "TrajectoryGroup | Coroutine[Any, Any, TrajectoryGroup]":
         ts = list(trajectories)
         if any(hasattr(t, "__await__") for t in ts):