Code Navigator — Understand any repo in 15 minutes

Every developer has joined a repo with no idea where to start. Code Navigator turns github.com into a guided map of the codebase you're looking at — right where you already are, with no server, no signup, and no data leaving your browser. BEFORE YOU EDIT ANYTHING • Dependency graph and impact analysis — see everything a file transitively affects before you touch it, with a risk tier and related tests. • Safe Change Checklist — a concrete, evidence-backed checklist for the file you're about to change. • "Why is this here?" and "What breaks if I change this?" — grounded AI narration on top of the real dependency graph, never a guess pretending to be a fact. GET PRODUCTIVE FAST • Core Systems detection — Authentication, API, Database, Payments, and more, auto-detected with an honest confidence score, not false certainty. • Guided reading tours through a system, in dependency order, with time estimates. • ⌘K search across the whole repo. • File tree, architecture diagrams, and criticality ratings (commits/contributors) fetched on demand. REVIEWING A PR • Explain This PR — a grounded summary of what changed, which systems are affected, overall risk, and a suggested review order. • Per-file impact and related-test counts for every changed file. STAYS OUT OF YOUR WAY • Fully client-side — no Code Navigator servers exist. • Bring your own GitHub token and AI key (Anthropic, OpenAI, Groq, Gemini — auto-detected — or any other OpenAI-compatible endpoint), both stored only in your browser and never sent anywhere else. • Works keyless within GitHub's public rate limit — graph features never require an AI key. • Live GitHub API budget tracking so you're never stranded mid-session. Best tried on a real, unfamiliar repo (e.g. expressjs/express) — the value is orienting you in a codebase too large to read file by file.