Slash commands control your session. I'll cover the ones you'll reach for most often:
/help: list all available commands/clear: start a fresh session, dropping all context/compact: summarize the conversation to free up context window space/cost: show how many tokens the current session has used/model: switch the underlying model mid-session/status: open the Settings interface, showing version, model, account, and connectivity
Run any of them by typing the command at the Claude prompt. They take effect immediately, so you don't need to restart your session.