# pfui Give Pi a consistent built-in working style when you have not chosen a custom system prompt. PFUI supplies a practical fallback prompt and makes Pi's installed documentation available to its bundled knowledge skill. ## Use it in Pi Nothing to invoke. PFUI activates automatically when Pi starts without a custom system prompt. Your own custom or forced system prompt takes precedence and is left unchanged. Ask Pi questions about its installed features when useful, for example: `How do I configure Pi in this installation?` The bundled `pi-knowledge` skill can locate relevant installed documentation for the agent. Install through [Installation](../../README.md#install).