Runtime ValueError during plan execution: \"Parameter input is expected to be parsed to <class 'int'> but is not.\" Traceback shows invalid literal for int() on unexpected string like date ('Monday, 17 June, 2024'). Plan executes wrong prior function, mismatching parameters for target function.

In Python SequentialPlanner, LLM generates XML plan with sequential function calls sharing a global context. Hallucinated/unnecessary functions (e.g., TimePlugin-date) execute first, polluting context variables (e.g., setting 'input' to date string). Later functions (e.g., MathPlugin-Subtract expecting int) fail type parsing on mismatched values.