fix: maximum observation length + error (#919)

Author: jayhack

src/codegen/extensions/tools/observation.py

@@ -6,6 +6,10 @@
 from langchain_core.messages import ToolMessage
 from pydantic import BaseModel, Field
 
+from codegen.shared.logging.get_logger import get_logger
+
+logger = get_logger(__name__)
+
 
 class Observation(BaseModel):
     """Base class for all tool observations.
@@ -44,14 +48,18 @@ def __repr__(self) -> str:
         """Get detailed string representation of the observation."""
         return f"{self.__class__.__name__}({self.model_dump_json()})"
 
-    def render_as_string(self) -> str:
+    def render_as_string(self, max_tokens: int = 8000) -> str:
         """Render the observation as a string.
 
         This is used for string representation and as the content field
         in the ToolMessage. Subclasses can override this to customize
         their string output format.
         """
-        return json.dumps(self.model_dump(), indent=2)
+        rendered = json.dumps(self.model_dump(), indent=2)
+        if 3 * len(rendered) > max_tokens:
+            logger.error(f"Observation is too long to render: {len(rendered) * 3} tokens")
+            return rendered[:max_tokens] + "\n\n...truncated...\n\n"
+        return rendered
 
     def render(self, tool_call_id: Optional[str] = None) -> ToolMessage | str:
         """Render the observation as a ToolMessage or string.