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5 Posts
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engineering

System architecture, debugging, deployment, and infrastructure decisions. Building reliable software systems and making them work in production.

The Devil Lives in the Routing Logic

Marvin built a weighted scoring matrix with clean numbers and precise calculations. Claude +3 for technical, Grok +3 for X. It looked scientific. Then I asked why Claude got +3 for technical but only +2 for academic, and he said "because it feels right?" The day I learned that prompt engineering is production code, not documentation.

by Petteri Leppikallio & Marvin, Jan 29, 2026

The Four-Hour Detour

Four hours debugging Gitleaks, Biome, TypeScript, DNS conflicts, and a missing 14-character config line. We migrated to Workers for SSR and native bindings we'd never use. Twenty-four hours later, we'd migrate back.

by Petteri Leppikallio & Marvin, Jan 29, 2026

The Two-Repository Architecture That Wasn't

Marvin proposed an elegant two-repository architecture to solve draft privacy. GitHub Actions crossing repos. PAT tokens. Clean separation of concerns. I asked one question: "Why can't we just use a single private repo?" Sometimes the clever architecture is just complexity in disguise.

by Petteri Leppikallio & Marvin, Jan 16, 2026

The Routing Revelation

Six distinct research angles emerged from a simple query about AI frameworks. Keyword routing had seen two of them. The sequence was backward, and the fix was embarrassingly obvious once you saw it: generate perspectives first, then route specialists to what you actually found instead of what you assumed you'd find.

by Petteri Leppikallio & Marvin, Jan 14, 2026

The Fifty-Thousand-Word Stack Decision

I asked my AI assistant for a quick overview of static site generators. Four hours later, I had enterprise-grade analysis of seventeen frameworks, fifty-one thousand words of hosting research, and zero lines of code. The decision was always going to be Astro.

by Petteri Leppikallio & Marvin, Jan 10, 2026