AIVO is the technical blog of Tú (tusgino). Writing slowly and understanding deeply about production-grade system architecture, cloud infrastructure and reading experience on the web.https://aivo.io.vn/en/https://aivo.io.vn/en/blog/coverage-100-ma-van-khong-chay/https://aivo.io.vn/en/blog/coverage-100-ma-van-khong-chay/A feature was completely dead in production while 178 tests were green and coverage held at 100%. Tests measure lines that ran, not the path that ships.Tue, 29 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/hoi-truoc-khi-ghi/https://aivo.io.vn/en/blog/hoi-truoc-khi-ghi/Permission is not a true/false flag. It is a seam with a contract, three sandbox modes that speak only about files, and a safe default: no answer means no.Mon, 28 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/cat-ngu-canh-van-kiem-toan-duoc/https://aivo.io.vn/en/blog/cat-ngu-canh-van-kiem-toan-duoc/Compaction deletes nothing. It only shadows a range on the surface sent to the model, records exactly which range, and leaves the original in the log for later.Sun, 27 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/mot-tool-call-di-qua-bay-chang/https://aivo.io.vn/en/blog/mot-tool-call-di-qua-bay-chang/A tool call passes seven stages before it reaches the tool body. Policy, hooks and sandboxing live there — and the tool itself need not know about them.Sat, 26 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/so-ghi-la-nguon-khong-phai-ban-sao/https://aivo.io.vn/en/blog/so-ghi-la-nguon-khong-phai-ban-sao/Everything the model sees must be in the log first. Context is never stored beside it — it is derived, and that is the difference between a source and a copy.Fri, 25 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/cung-mot-vong-lap-hai-kien-truc/https://aivo.io.vn/en/blog/cung-mot-vong-lap-hai-kien-truc/Every harness has a log, a tool registry, a context budget and a permission layer. They differ in which of those you may replace — I read four to answer.Thu, 24 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/harness-bat-dau-tu-cho-nao/https://aivo.io.vn/en/blog/harness-bat-dau-tu-cho-nao/The loop is only a coordinator. Four parts turn it into a harness: a durable log, a tool registry, a context budget, and a permission layer, all four pluggable.Wed, 23 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/system-one-typed-decisions/https://aivo.io.vn/en/blog/system-one-typed-decisions/Explore System One AI with TypeSafe Jev: replace slow LLMs with Typed Decisions, probability distributions and the three primitives Choice, Score and Noul.Tue, 22 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/vong-while-chay-duoc-toi-luc-khong/https://aivo.io.vn/en/blog/vong-while-chay-duoc-toi-luc-khong/An agent loop runs in ten lines. The production version of that same loop is 101 lines, and every extra line marks a place it used to break. Here are the four.Tue, 22 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/model-de-nghi-code-thuc-thi/https://aivo.io.vn/en/blog/model-de-nghi-code-thuc-thi/The model sees only a tool declaration, never its execution. A tool call is a structured request your code validates, authorises, and then decides to run.Mon, 21 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/cua-so-ngu-canh-khong-phai-tri-nho/https://aivo.io.vn/en/blog/cua-so-ngu-canh-khong-phai-tri-nho/A context window is a finite budget, not a memory. On the same request, two published token ratios differ by 1.6x, and you cannot tell which one you are on.Sun, 20 Sep 2026 00:00:00 GMThttps://aivo.io.vn/en/blog/mot-lan-goi-api-roi-quen-het/https://aivo.io.vn/en/blog/mot-lan-goi-api-roi-quen-het/Every API call is a pure function: text in, text out, then nothing. The memory you think the model has is history you resend yourself, and you pay for it.Sat, 19 Sep 2026 00:00:00 GMT