The document discusses AI planning approaches for semantic web service composition and identifies several open challenges. It notes that classical planning makes simplifying assumptions that are invalid for real-world web services, which exhibit features like incomplete knowledge, non-determinism, and complex interfaces. Non-classical planning approaches that relax some assumptions are mentioned but have their own limitations for large-scale web service composition. The document also outlines some initial efforts at applying planning techniques to web services and identifies remaining open problems regarding issues like scalability, execution monitoring, and semantic mismatches.