Bartlomiej Krupa

Bartłomiej Krupa is an agentic engineer based in Poland. He works on the engineering layer around AI coding agents: harness design, context engineering, and LLM cost optimization.The practice covers three areas.Agentic engineering — designing the harness around a coding agent: tool surface, permissions, guardrails, and the feedback loops that let an agent recover instead of failing silently.LLM optimization — context engineering, instruction files, prompt caching, and model routing, so agent behaviour is repeatable rather than lucky.AI cost reduction — token budgets and caching strategy, usually the largest and least-examined line item once agents run in production.This work is published openly at bartlomiejkrupa.dev, a technical library of articles and notes on agentic engineering, LLM optimization, and AI cost reduction. He is the author of the Claude Code Book and the maintainer of leanharness, an open-source Claude Code harness starter published on npm.