Where does the reasoning behind your product decisions actually live?

You probably remember what you decided.

But can you reconstruct why?

A customer said something in a call.

You explored it with ChatGPT.

There was an assumption in a doc somewhere.

You considered three directions.

You rejected two.

Then you shipped one.

Three weeks later, you remember the decision, but the reasoning behind it is scattered across chats, notes, docs, and your own memory.

I've been thinking a lot about this while talking to founders.

Tasks are usually tracked.

Decisions sometimes are.

But the evidence, assumptions and reasoning behind those decisions often aren't.

Curious how other founders handle this:

When you need to revisit an important product decision from a few weeks or months ago, where do you actually look?