diff --git a/alphatrion/log/log.py b/alphatrion/log/log.py
index c88ac791..dc16cb69 100644
--- a/alphatrion/log/log.py
+++ b/alphatrion/log/log.py
@@ -39,11 +39,14 @@ async def log_artifact(
 # log_params is used to save a set of parameters, which is a dict of key-value pairs.
 # should be called after starting a trial.
 async def log_params(params: dict):
+    trial_id = current_trial_id.get()
+    if trial_id is None:
+        raise RuntimeError("log_params must be called inside a Trial.")
     runtime = global_runtime()
     # TODO: should we upload to the artifact as well?
     # current_trial_id is protect by contextvar, so it's safe to use in async
     runtime._metadb.update_trial(
-        trial_id=current_trial_id.get(),
+        trial_id=trial_id,
         params=params,
     )
 
@@ -63,6 +66,9 @@ async def log_metrics(metrics: dict[str, float]):
     exp = runtime.current_exp
 
     trial_id = current_trial_id.get()
+    if trial_id is None:
+        raise RuntimeError("log_metrics must be called inside a Trial.")
+
     trial = exp.get_trial(id=trial_id)
     if trial is None:
         raise RuntimeError(f"Trial {trial_id} not found in the database.")
diff --git a/alphatrion/run/run.py b/alphatrion/run/run.py
index 672827bf..60c75554 100644
--- a/alphatrion/run/run.py
+++ b/alphatrion/run/run.py
@@ -16,13 +16,21 @@ def __init__(self, trial_id: uuid.UUID):
     def id(self) -> uuid.UUID:
         return self._id
 
-    def _start(self):
+    def _start(self, call_func: callable) -> asyncio.Task | None:
         self._id = self._runtime._metadb.create_run(
             project_id=self._runtime._project_id, trial_id=self._trial_id
         )
 
-    def register_task(self, task: asyncio.Task):
-        self._task = task
+        # current_run_id context var is used in tracing workflow/task decorators.
+        token = current_run_id.set(self.id)
+        try:
+            # The created task will also inherit the current context,
+            # including the current_trial_id, current_run_id context var.
+            self._task = asyncio.create_task(call_func())
+        finally:
+            current_run_id.reset(token)
+
+        return self._task
 
     async def wait(self):
         await self._task
diff --git a/alphatrion/trial/trial.py b/alphatrion/trial/trial.py
index 9e126bd3..1410d532 100644
--- a/alphatrion/trial/trial.py
+++ b/alphatrion/trial/trial.py
@@ -1,4 +1,3 @@
-import asyncio
 import contextvars
 import os
 import uuid
@@ -7,7 +6,7 @@
 from pydantic import BaseModel, Field, model_validator
 
 from alphatrion.metadata.sql_models import COMPLETED_STATUS, TrialStatus
-from alphatrion.run.run import Run, current_run_id
+from alphatrion.run.run import Run
 from alphatrion.runtime.runtime import global_runtime
 from alphatrion.utils.context import Context
 
@@ -308,20 +307,11 @@ def start_run(self, call_func: callable) -> Run:
         :return: the Run instance."""
 
         run = Run(trial_id=self._id)
-        run._start()
+        task = run._start(call_func)
+        if task is None:
+            raise RuntimeError("Failed to start the run task.")
         self._runs[run.id] = run
-
-        # current_run_id context var is used in tracing workflow/task decorators.
-        token = current_run_id.set(run.id)
-        try:
-            # The created task will also inherit the current context,
-            # including the current_trial_id, current_run_id context var.
-            task = asyncio.create_task(call_func())
-        finally:
-            current_run_id.reset(token)
-
         self._running_tasks[run.id] = task
-        run.register_task(task)
 
         task.add_done_callback(lambda t: self._running_tasks.pop(run.id, None))
         task.add_done_callback(lambda t: self._runs.pop(run.id, None))