Inside the Harness: Deterministic Systems

Our short summary of Klaviyo’s engineering write-up. The full story, with all the detail, is on their blog.

Problem

Managing massive context and ensuring AI agents follow strict guardrails was hard.

They created a cascading disclosure system, routing rules, token caps, and pre‑tool hooks to keep the analytics agent deterministic and efficient.

Want the architecture, code and numbers? They’re in the original post.