Show HN: Mindwalk – Replay coding-agent sessions on a 3D map of your codebase

A developer released Mindwalk, an open-source visualization tool that replays coding-agent sessions on a 3D map of a codebase, allowing users to see where an AI agent searched, read, and edited code. The tool runs locally, supports Claude Code and Codex session logs, and is available via GitHub.

A visualization tool that replays coding-agent sessions on a 3D map of your codebase. A session log records what an agent did, but not how it understood the task: which parts of the repo it treated as relevant, where it explored before it acted, whether its footprint matched the scope you had in mind. Reading the raw JSONL line by line doesn't answer any of that. Draw the repository as a night map, and play the session back as light moving through it: where the agent searched, read, and edited, the map glows — everything else stays dark. The agent's understanding of the task becomes a shape you can see at a glance. One Go binary reads Claude Code and Codex session logs, fully local; no session data leaves your machine. curl -fsSL https://raw.githubusercontent.com/cosmtrek/mindwalk/master/scripts/install.sh | sh export PATH="$HOME/.local/bin:$PATH" mindwalk The installer verifies the binary against checksums.txt and installs to ~/.local/bin override with INSTALL DIR ; pin a release with VERSION . Windows archives are on GitHub Releases https://github.com/cosmtrek/mindwalk/releases . To build from source: make setup && make build → bin/mindwalk . With no arguments, mindwalk scans ~/.claude/projects and ~/.codex/sessions , serves the UI on a random local port, and opens a browser: mindwalk serve --port N --no-open --claude-dir DIR --codex-dir DIR mindwalk open --no-open <session.jsonl open one specific session mindwalk build <repo -o out write the repository citymap JSON mindwalk trace <session -o out write the normalized trace JSON Tree / Terrain views — the repo as a radial tree or a treemap plain; glow ∝ how deeply and how often a file was touched. Touch states — each file keeps its deepest touch: seen moss green , read moon white , edited warm amber , unvisited dark . The HUD folds friction signals — error rate, churned files, edits after the last verify — into a review strip. Playback deck — scrub or play the session over a bucketed histogram of the run. Bars sit on a cool/warm spectrum: observation stays cool search, read, exec , mutation glows warm edit, verify , so editing phases jump out at a glance. Timeline marks — ◇ context compactions, ○ subagent launches, › user turns; every mark is a click-to-jump target. Inspector — click a file to pin its visit history; click a visit row to jump the playhead to that moment. Keyboard: Space play/pause · ← / → step ⇧ ×10 · Home / End ends · S speed · E next edit · X next error · M next mark · ⌘B session rail. Two artifacts, kept deliberately separate: - a trace — the session log normalized into an ordered stream of file-touch events internal/adapter , one adapter per agent format ; - a citymap — a deterministic layout of the repository internal/citymap ; the same tree always produces the same map, so replays are comparable across sessions. A local Go server internal/server joins the two and serves the React/Three.js frontend web . schema/ mirrors the exported JSON contracts. Issues and pull requests are welcome. To get a working dev setup: make setup install frontend dependencies make serve dev server on :8765, serving web/dist from the working tree make test go test + frontend build — run before sending a PR make build regenerate embedded assets and bin/mindwalk Ground rules see AGENTS.md /cosmtrek/mindwalk/blob/master/AGENTS.md for the full architecture notes : - Keep the boundaries: adapters don't know about rendering, citymap generation doesn't depend on playback, the server just connects the two. - Keep Go code gofmt -ed; never hand-edit internal/server/static — regenerate it with make build . - When trace or citymap JSON shapes change, update schema/ and the relevant tests in the same change.