Never capture a critical decision on chat.
When a decision matters - technically, operationally, or organizationally - it deserves a place where it can be found later. A short email or a lightweight document is usually enough. The key is that months later, someone should be able to understand what was decided and why, without replaying a chat thread.
Chat tools (like Slack and Microsoft Teams) are great for speed, but they are a poor ‘system of record’. Messages get buried, context gets fragmented across threads, future readers have to reconstruct intent from partial conversations, and that’s hard.
So, it is better to chat, reach an agreement, and then drop a summarized decision over email or in a document.
This also solves another problem - looping people in. With email or a document, it is easier to include others when needed. And if a decision affects more than one team or system, sharing becomes necessary by default, which makes email or a doc the better option.
In my experience, writing a few clear lines right after a decision is far cheaper than rediscovering it later. People join, people leave, priorities shift. A short, structured, searchable note keeps the team aligned as things change.
Of course, not every choice needs a ‘ceremony’. Small, reversible calls can live in chat when the scope is local, and the impact is limited.
This is one habit that has helped me throughout my career, right from the early days until today, and it has prevented a surprising amount of confusion later.