Luc Joosten — Writing https://lucjoosten.nl/writing Notes on AI-assisted engineering, DevOps, and keeping software honest after the demo. Fabric integrations need a boundary https://lucjoosten.nl/writing/fabric-gateway-contract https://lucjoosten.nl/writing/fabric-gateway-contract Sat, 22 Aug 2026 00:00:00 GMT Direct consumer-to-Fabric integrations make every app understand provider-specific limits, identities, and job semantics. I am designing a gateway so consumers can depend on one async contract instead. The useful part of a Fabric gateway is coordination https://lucjoosten.nl/writing/fabric-gateway-load-bearing-mechanics https://lucjoosten.nl/writing/fabric-gateway-load-bearing-mechanics Sat, 22 Aug 2026 00:00:00 GMT An API wrapper does not solve Fabric throttling. The hard value is shared polling, capacity-aware backoff, fair admission, and reliable fan-out across consumers. Experimental is a status, not a mood https://lucjoosten.nl/writing/experimental-is-a-status https://lucjoosten.nl/writing/experimental-is-a-status Fri, 21 Aug 2026 00:00:00 GMT I keep unfinished systems on the public site. The useful part is labeling them so a visitor is not sold a product that is still a design doc. A failing test is the incident, not the afterthought https://lucjoosten.nl/writing/reproduction-before-patch https://lucjoosten.nl/writing/reproduction-before-patch Fri, 21 Aug 2026 00:00:00 GMT Autofix demos start with a generated patch. I want the opposite gate: reconstruct the crash as a test that fails on current code, then you may propose a fix. The agent should propose, not assume https://lucjoosten.nl/writing/agents-propose-not-assume https://lucjoosten.nl/writing/agents-propose-not-assume Thu, 20 Aug 2026 00:00:00 GMT Permissionless agents look fast in a demo. In a real repo they spend your week on silent side effects. Proposal-first is slower in the hour and faster in the week. Treat the model like a flaky HTTP dependency https://lucjoosten.nl/writing/models-are-dependencies https://lucjoosten.nl/writing/models-are-dependencies Tue, 18 Aug 2026 00:00:00 GMT An LLM is not a personality in your app. It is a nondeterministic service with a worse SLO than Postgres. Design the boundary that way. RAG is a retrieval problem wearing a chatbot costume https://lucjoosten.nl/writing/rag-is-not-a-chatbot https://lucjoosten.nl/writing/rag-is-not-a-chatbot Fri, 14 Aug 2026 00:00:00 GMT The chat UI is the easy part. The hard part is what you retrieve, what you refuse to retrieve, and how you prove the answer came from somewhere. Two visual systems, one content model https://lucjoosten.nl/writing/two-themes-one-content https://lucjoosten.nl/writing/two-themes-one-content Wed, 12 Aug 2026 00:00:00 GMT Builder and editorial on this site share facts, routes, and DuckDB. The failure mode is forking pages per theme. The working model is tokens plus a few layout variants. If it is not deployable, it is not done https://lucjoosten.nl/writing/done-means-it-deploys https://lucjoosten.nl/writing/done-means-it-deploys Sat, 08 Aug 2026 00:00:00 GMT Demos and local happy paths are not delivery. I count work finished when someone else can run it, see it fail, and know who owns the failure.