GitHub Copilot history: onboarding an engineer

How does someone new find out why this code was written this way?

Why this is hard

A new engineer inherits decisions, not just code. When a large share of the codebase was written with AI, the reasoning lives in conversations rather than in commit messages — and those conversations are on other people's laptops, if they still exist.

What GitHub Copilot specifically does to you here

Chat sessions record the conversation but not the resulting diff, so they explain intent without showing what landed. Useful context for a new engineer, and not a substitute for the change itself.

find "$HOME/Library/Application Support/Code/User/workspaceStorage" -path '*chatSessions/*' -type f | wc -l

Where GitHub Copilot keeps this in the first place: ~/Library/Application Support/Code/User/workspaceStorage/<hash>/chatSessions/. History is keyed to the workspace path. Rename or move the project and the chat panel comes up empty.

What a working answer looks like

A working answer means the reasoning behind a file is reachable from the file, by someone who was not there when it was written.

Start by measuring what you have. npx promptwake doctor reports what every AI tool on the machine is holding and how much of it sits inside a deletion window — no account, writes nothing, sends nothing anywhere. If the conclusion is that the record should not depend on one laptop, that is what PromptWake captures: prompt, response and the resulting diff, local by default and synced into a shared timeline on the paid tiers.