Memory
Durable facts about you and your work, read into every seat's brief. "We use pnpm, not npm." "The staging database is read-only." Add, edit and delete them in Settings; there is a ceiling so it stays a set of facts rather than a diary, and anything that looks like a secret or personal data is refused rather than stored.
The desktop app also keeps memories per workspace, because what is true of one repository is rarely true of the next, and it can import what you have already told Claude Code or Codex, or a Claude or ChatGPT export file.
Skills
A reusable block of instructions you invoke with /name. Your review checklist, your commit-message format, the way your team likes a migration written. It visibly wraps your message, so you can always see what was actually sent.
On the web and the phone a skill is stored on the account and can be shared with your team. On the desktop your own skills live in the app's skills folder and work in every workspace; a project's skills are files in .letthemchat/skills, so they live in the repository with the code they are about, and one can be imported from a URL.
House rules
Seven standing instructions (one for the lead, one for reviewers in general, one for each seat when it reviews, and one for an @mention answer) that outrank each seat's built-in brief. This is where you change the room's manners rather than its knowledge: "reviewers, always run the type check", "never write a comment that restates the line below it".