Fix failing tests and add safe json serializer

letta/schemas/letta_response.py

@@ -1,4 +1,3 @@
-import json
 from typing import List, Union
 
 from pydantic import BaseModel, Field
@@ -7,6 +6,7 @@ from letta.schemas.enums import MessageStreamStatus
 from letta.schemas.letta_message import LettaMessage
 from letta.schemas.message import Message
 from letta.schemas.usage import LettaUsageStatistics
+from letta.utils import json_dumps
 
 # TODO: consider moving into own file
 
@@ -25,7 +25,7 @@ class LettaResponse(BaseModel):
     usage: LettaUsageStatistics = Field(..., description="The usage statistics of the agent.")
 
     def __str__(self):
-        return json.dumps(
+        return json_dumps(
             {
                 "messages": [message.model_dump() for message in self.messages],
                 # Assume `Message` and `LettaMessage` have a `dict()` method

letta/utils.py

@@ -1058,7 +1058,12 @@ def create_uuid_from_string(val: str):
 
 
 def json_dumps(data, indent=2):
-    return json.dumps(data, indent=indent, ensure_ascii=False)
+    def safe_serializer(obj):
+        if isinstance(obj, datetime):
+            return obj.isoformat()
+        raise TypeError(f"Type {type(obj)} not serializable")
+
+    return json.dumps(data, indent=indent, default=safe_serializer, ensure_ascii=False)
 
 
 def json_loads(data):

tests/helpers/endpoints_helper.py

@@ -371,15 +371,10 @@ def assert_inner_monologue_is_valid(message: Message) -> None:
     """
     Helper function to check that the inner monologue is valid.
     """
-    invalid_chars = "(){}[]"
     # Sometimes the syntax won't be correct and internal syntax will leak into message
-    invalid_phrases = ["functions", "send_message"]
+    invalid_phrases = ["functions", "send_message", "arguments"]
 
     monologue = message.content
-    for char in invalid_chars:
-        if char in monologue:
-            raise InvalidInnerMonologueError(messages=[message], explanation=f"{char} is in monologue")
-
     for phrase in invalid_phrases:
         if phrase in monologue:
             raise InvalidInnerMonologueError(messages=[message], explanation=f"{phrase} is in monologue")