I am constantly having NPE because it is common for small LLMs hallucinate and try to call non existing function.

java.lang.NullPointerException: Cannot invoke "io.github.ollama4j.tools.ToolFunction.apply(java.util.Map)" because "toolFunction" is null
        at io.github.ollama4j.OllamaAPI.chatStreaming(OllamaAPI.java:921)

A suggestion is to avoid these NPEs by telling the LLM that the function it tried to call is not registered.