diff --git a/pyproject.toml b/pyproject.toml
index c274597..464cc51 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "synth-sdk"
-version = "0.2.66"
+version = "0.2.67"
 description = ""
 authors = [{name = "Synth AI", email = "josh@usesynth.ai"}]
 license = {text = "MIT"}
diff --git a/setup.py b/setup.py
index b024132..776bd57 100644
--- a/setup.py
+++ b/setup.py
@@ -2,7 +2,7 @@
 
 setup(
     name="synth-sdk",
-    version="0.2.66",
+    version="0.2.67",
     packages=find_packages(),
     install_requires=[
         "opentelemetry-api",
diff --git a/synth_sdk/tracing/abstractions.py b/synth_sdk/tracing/abstractions.py
index e307360..e9f9664 100644
--- a/synth_sdk/tracing/abstractions.py
+++ b/synth_sdk/tracing/abstractions.py
@@ -65,8 +65,8 @@ class Event:
     def to_dict(self):
         return {
             "event_type": self.event_type,
-            "opened": self.opened,
-            "closed": self.closed,
+            "opened": self.opened.isoformat() if isinstance(self.opened, datetime) else self.opened,
+            "closed": self.closed.isoformat() if isinstance(self.closed, datetime) else self.closed,
             "partition_index": self.partition_index,
             "agent_compute_steps": [
                 step.to_dict() for step in self.agent_compute_steps