Change8
Error1 reports

Fix ParametersValidationException

in Chainlit

Solution

ParametersValidationException in Chainlit often arises when the data types defined in your chainlit.ToolMessage parameters or cl.user_session are incompatible with the actual data being passed during runtime, or are missing required fields. Ensure that all data being passed to these functions adheres to the specified data types and that all required fields are present according to your Python type hints or Pydantic models. Validate incoming data and consider using try-except blocks to gracefully handle potential type mismatches, providing informative error messages when validation fails.

Related Issues

Real GitHub issues where developers encountered this error:

Timeline

First reported:Sep 8, 2025
Last reported:Sep 8, 2025

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