https://murn.eu/blog Thoughts on design, technology, free time, and a little philosophy. en https://murn.eu/blog/port-test https://murn.eu/blog/port-test Sat, 04 Jul 2026 00:00:00 GMT The same repo holds the API twice — NestJS and a Spring Boot port serving one hand-written contract. What transferred unchanged between them is where the engineering actually lives. engineering philosophy https://murn.eu/blog/two-envs https://murn.eu/blog/two-envs Tue, 30 Jun 2026 00:00:00 GMT NODE_ENV is a semantics switch that libraries branch on, not a deployment tier. Set it to staging and your rehearsal runs different code paths than the show. engineering https://murn.eu/blog/knob-debt https://murn.eu/blog/knob-debt Sat, 27 Jun 2026 00:00:00 GMT The retry policy is three hardcoded constants, and the decision record says why: a config option promises that every value works. Unused knobs are debt, not flexibility. engineering https://murn.eu/blog/upstream-clock https://murn.eu/blog/upstream-clock Tue, 23 Jun 2026 00:00:00 GMT The weather source publishes on a ~25-minute cycle, so the refresh cron fires at :27 — cache freshness is a property of the upstream's rhythm, not of your TTL. engineering https://murn.eu/blog/boundary-tripwire https://murn.eu/blog/boundary-tripwire Sat, 20 Jun 2026 00:00:00 GMT The API returns six fields per station but validates the upstream's entire shape. Drift in the eighty fields you ignore is the earliest warning about the six you depend on. engineering https://murn.eu/blog/typed-absence https://murn.eu/blog/typed-absence Tue, 16 Jun 2026 00:00:00 GMT One weather station reports no temperature at all. Encode that as 0 or drop the key, and every consumer inherits the bug — absence belongs in the contract, typed. engineering https://murn.eu/blog/drift-direction https://murn.eu/blog/drift-direction Sat, 13 Jun 2026 00:00:00 GMT Doc generation doesn't stop code and contract from disagreeing — it decides which one drifts unreviewed. The artifact a stakeholder approved should be the one the code chases. engineering https://murn.eu/blog/relitigation https://murn.eu/blog/relitigation Tue, 09 Jun 2026 00:00:00 GMT My test folder got migrated twice — same move, same commit message, days apart. An agent session starts with no memory, and an unwritten decision is just an accident it feels free to fix. engineering https://murn.eu/blog/control-plan https://murn.eu/blog/control-plan Sat, 06 Jun 2026 00:00:00 GMT I had the model write its full project plan, committed it, and added a rule to never follow it. The unedited default is what makes judgment visible. engineering philosophy https://murn.eu/blog/disposable https://murn.eu/blog/disposable Tue, 02 Jun 2026 00:00:00 GMT Vibe coding versus agentic engineering is sold as a skill tier. It is really a per-artifact call: most agent output is disposable, and verification only pays once an output crosses the boundary where a second reader has to trust it. engineering llm https://murn.eu/blog/executable-questions https://murn.eu/blog/executable-questions Tue, 02 Jun 2026 00:00:00 GMT The brief's openapi.yaml was missing, so I committed my own. A question that ships with its answer turns authoring into a veto — and never blocks. engineering https://murn.eu/blog/pattern-shopping https://murn.eu/blog/pattern-shopping Tue, 26 May 2026 00:00:00 GMT Pattern catalogs read forward — name, then move, then constraint. Engineering runs the other way. Reading them as curriculum produces moves imported from a vocabulary rather than earned from a failure. engineering llm https://murn.eu/blog/rule-drift https://murn.eu/blog/rule-drift Mon, 25 May 2026 00:00:00 GMT Osmani's ratchet — every mistake becomes a rule — is the accretion move. The second move is consolidation: rules that live in one canonical file cannot drift, and most harness write-ups skip it. engineering llm https://murn.eu/blog/thinking-in-code https://murn.eu/blog/thinking-in-code Sat, 23 May 2026 00:00:00 GMT For ambiguous problems, writing the code is where the thinking happens — not a transcription step after the thinking has finished. The medium and the thought go together. engineering llm https://murn.eu/blog/judgement-shaped-problems https://murn.eu/blog/judgement-shaped-problems Thu, 30 Apr 2026 00:00:00 GMT Most production 'agents' are integrations in costume. The test is where the if/else lives — in code, or in inference. engineering https://murn.eu/blog/the-catch https://murn.eu/blog/the-catch Tue, 21 Apr 2026 00:00:00 GMT LLMs write perfect plans, detailed specifications, and complete architectures. Nobody ever builds any of it. engineering llm https://murn.eu/blog/asking-is-not-enough https://murn.eu/blog/asking-is-not-enough Wed, 18 Mar 2026 00:00:00 GMT Most LLM workflows fail not because the model gets it wrong, but because nobody defined what right looks like before calling it. engineering llm https://murn.eu/blog/prompts-as-pipelines https://murn.eu/blog/prompts-as-pipelines Sun, 01 Mar 2026 00:00:00 GMT Prompt engineering is not the art of writing one better prompt — it is the discipline of breaking the work into phases that can fail independently. engineering llm https://murn.eu/blog/boring https://murn.eu/blog/boring Thu, 05 Feb 2026 00:00:00 GMT The best software is the kind where nothing happens. Everything was planned, written, tested, and deployed — and it just works. engineering https://murn.eu/blog/on-simplicity https://murn.eu/blog/on-simplicity Sat, 10 Jan 2026 00:00:00 GMT Simplicity is not the absence of complexity — it is the resolution of it. design https://murn.eu/blog/return-value https://murn.eu/blog/return-value Mon, 05 Jan 2026 00:00:00 GMT Most blog posts get published because the writer wrote them. This blog is built around a different test — would the reader keep it? philosophy