Deterministic Task Planning: How AI Agents Execute Complex Plans Without Source Code

This challenges the widespread assumption that LLM non-determinism prevents reliable agent behavior, demonstrating instead that natural language specifications can enforce deterministic procedural execution across multi-step tasks. The experiment proves traditional software design principles—clear specifications, modular abstraction, and separation of concerns—remain essential in the agentic era, not obsolete. This fundamentally reshapes how we can architect complex multi-agent systems, moving from hardcoded behavioral logic to formal specification-driven design.