About
Bartłomiej Krupa
Ten-plus years in IT. I write about harness engineering, agentic systems, and making LLM systems reliable and cheap to run in production — the articles, notes, and tool picks on this site. Currently on a contract at Brand24. What keeps me in this field is building new things - whatever I learn goes straight into practice, not a slide deck.
What_I_do
LLM cost optimization
The first lever is routing: send each task to the model that actually fits it, through orchestration, instead of defaulting to whatever's biggest. The second is the context window - keep it tight, let in only what the task needs. Together they control cost more than any caching trick, and I check the trade-off against evals, not gut feel.
Harness engineering
Guardrails on the critical paths, so a bad action gets caught before it executes, not after. Validation, feedback loops, fallbacks, monitoring: the rest of the harness that turns probabilistic output into something dependable. Models are unreliable by nature. Harnesses are engineered not to be.
AI-assisted engineering
Rolling out agents and AI coding tools across teams is the easy part. Teaching people to actually use them well - instead of just handing over access and hoping - is the part that matters. Do that, and speed goes up along with the team's own skill, not instead of it.
Independence
This site is a personal project. What I publish condenses publicly available knowledge - not employer policy or proprietary know-how.Read the full disclaimer.
Contact
Working on the same problems? Email is the fastest way to reach me.