Why AI Agents Need Deterministic API Workflows

AI agents consuming APIs at scale face serious reliability and accuracy problems — LLM accuracy drops to 30% when exposed to 300+ endpoints. The Arazzo Specification, from the OpenAPI Initiative, addresses this by defining deterministic, machine-readable multi-API workflows that give agents structured execution paths, error handling, and predictable runtime behavior. Unlike MCP, which exposes tools but doesn't orchestrate them reliably, Arazzo provides the 'recipes' that turn raw API descriptions into dependable workflows. The two can work together: MCP for discovery and exposure, Arazzo for deterministic execution. Arazzo also improves auditability, compliance, and living documentation for both humans and machines.