Beyond Static Endpoints: Tool Programs as an Interface for Flexible Agentic Web Services
For LLM-based agents invoking web services, ToolPro addresses the inefficiency of static endpoints for complex workflows, offering significant performance gains.
ToolPro represents agent tool intent as executable programs, reducing end-to-end latency by up to 53.4% and client-side traffic by up to 96.1% on real-world workflows.
In the agentic web era, LLM-based agents increasingly invoke web services as tools, yet most interfaces remain \emph{static endpoints} that poorly express long-horizon workflows with loops, conditionals, joins, and retries. We present ToolPro, which represents an agent's tool intent as an \emph{executable tool program} that compactly encodes multi-step service interactions with explicit effect types. ToolPro combines constraint-guided program construction, effect-aware replay for exactly-once state-modifying calls, and a profile-driven policy that decides when program execution outperforms stepwise calling. We instantiate ToolPro over MCP-style services with WebAssembly sandboxing and evaluate it on diverse workflows of real-world applications. ToolPro reduces end-to-end latency by up to 53.4\% and client-side traffic by up to 96.1\%, with larger gains under higher network latency and workflow complexity.