I built rewind — a CLI that reads your git repo and tells you in plain english where you left off. But the interesting part isn't what it does, it's how it actually works under the hood. The core problem with context The naive approach would be to just dump your entire git history into an LLM and ask it to summarize. That works but it's wasteful and noisy. A repo with 500 commits would burn through tokens on irrelevant history. So rewind only collects what's actually relevant right now: Current branch name Last 10 commits with messages and timestamps Full staged diff Full unstaged diff List of untracked files That's it. Everything else is noise. Structuring the prompt The context gets assembled into a structured prompt that tells the LLM exactly what role it's playing and what output format is expected. The key insight here is that you don't want a summary — you want a briefing. Those are different things. A summary recaps what happened. A briefing tells you what matters right now and what's unfinished.…