Using RAII to Add Budget and Action Guardrails to Rust AI Agent

Rust is a strong fit for agent runtimes, but until now it has largely lacked a first-class runtime and budget enforcement layer. We built cycles to add pre-execution budget and action control to Rust agents with an API that leans into ownership and compile-time safety. The key ideas: commit(self) consumes the guard, so double-commit becomes a compile-time error #[must_use] helps catch ignored reservations Drop triggers best-effort release if a guard is never finalized one lifecycle works across simple calls, streaming, and multi-agent workflows The guide walks through three integration levels: with_cycles() for simple LLM/tool calls ReservationGuard for streaming and manual commit low-level client methods for custom lifecycles It also covers caps-aware execution: max token caps tool allow/deny lists step limits cooldowns And a practical rollout path: start in dry_run inspect decisions and caps move to partial enforcement then hard limits Full guide: https://runcycles.io/blog/how-to-add