pipecat/changelog/4404.added.md

• Added an opt-in add_tool_change_messages flag to the LLM aggregators (set via LLMContextAggregatorPair(..., add_tool_change_messages=True)) that appends a developer-role message to the context whenever LLMSetToolsFrame changes the set of advertised standard tools. Helps the LLM stay coherent across mid-conversation tool changes, mitigating several flavors of tool-call-related hallucination: calling tools that have been removed, avoiding tools that have been re-added, and hallucinating output (made-up answers or tool-call-shaped non-tool-calls) when tools are unavailable.