codemap

Problem: When a developer changes a file, the hardest question in code review is "what else could this break?" Reviewers read the diff in isolation, guess at callers, and often miss the tests that matter. Generic AI chat does not help much either: pasting code into a chatbot gives confident answers that are not grounded in how the repository is actually connected. Solution: codemap is an open-source local tool that runs inside any Git repository and opens a live, interactive map in the browser. A Go backend scans the repo, detects Go and TypeScript relationships (calls and imports), and tracks working-tree and branch changes against a base revision. A Svelte frontend shows files as cards with colored connection threads, grouped into frontend, backend and tests. For the IBM Bob 2.0 hackathon we added two AI features built on one principle: codemap supplies deterministic facts, IBM Bob supplies the explanation. 1. Analyze impact with Bob: select a changed file and codemap builds a structured ImpactContext: the diff, the files that call it, the files it depends on, and related tests (found through the graph and naming conventions). Bob receives that evidence and returns a summary, the affected areas, the reasoning, and which tests to review. 2. Explain the flow with Bob: drag a box around several files and Bob returns a plain-English summary plus numbered steps showing how the code runs through them. This is useful for onboarding onto unfamiliar code. Target users: developers reviewing their own changes before a PR, code reviewers, and engineers new to a codebase. What makes it unique: Bob is never asked to guess the architecture. Every answer is grounded in real Git and graph evidence, and the UI shows that evidence (callers, dependencies, related tests) next to Bob's reasoning so developers can verify it. Answers are cached by a hash of the exact evidence, so re-checking unchanged code is instant and costs nothing, while any code edit automatically triggers a fresh analysis. Bob runs through Bob Shell in read-only "ask" mode with turn and cost caps, so it explains but never edits your code. If Bob is unavailable, codemap shows a clear error instead of a fake answer, and the rest of the map keeps working. It runs locally with one command (make dev), needs no database or cloud setup, and works on any Git project.