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To find real code ownership and bus factor, use a tool that reads git history: git-fame or Git Truck for a quick look, CodeScene for a paid dashboard with an off-boarding simulation, and repowise for per-file owners, bus factor and fading ownership in the CLI and in coding agents. GitHub CODEOWNERS is not an analysis tool. It records who is declared responsible, which can differ from who wrote the code.
Vendor facts below are as of November 2026, from each project's own pages linked in the text.
| Tool | Source of truth | Bus factor number | Output | Cost |
|---|---|---|---|---|
| GitHub CODEOWNERS | Declared in a file | No | Review requests | Part of GitHub |
| git-fame | git blame | Not documented | Per-author table | Open source |
| Git Truck | Git history | Not documented | Visual map | MIT |
| CodeScene | Git history | Off-boarding simulation | Dashboard | Commercial |
| repowise | git blame and history | Yes, per file and repo | CLI, dashboard, MCP | AGPL-3.0, free OSS CLI |
Scroll the table sideways to see every column.
We build repowise, so weigh our entry accordingly. The measurements we publish about it, with their methods, are on the benchmarks page.
Declared versus actual ownership
Declared ownership is who a file says is responsible; actual ownership is who has been changing it. They drift apart when people leave, teams reorganize or a file is written by someone outside the owning team. Bus factor is the number of people who can leave before the code becomes hard to maintain, and it only makes sense from actual history. Background: what is bus factor, code ownership and the ownership and bus factor guide.
GitHub CODEOWNERS
CODEOWNERS maps file patterns to people or teams and requests their review automatically when a pull request touches those files. The file lives in .github/, the root or docs/, applies per branch, and with branch protection "Require review from Code Owners" can make owner approval mandatory. Owners need write access (GitHub docs).
It does not derive owners from commits. Pick CODEOWNERS for review routing and governance, and check it against git history for staleness.
git-fame
git-fame prints per-author lines, commits and files from git blame. The Python tool installs with pip install git-fame and can also estimate hours or months per author (GitHub). Its README does not describe a bus factor figure, so you read the table yourself: one author holding most surviving lines is the signal.
Pick git-fame if you want a fast repo-wide table with no setup.
Git Truck
Git Truck is a visual map of a repository that shows who changed the most lines per file and how activity moved over time. It runs with npx -y git-truck or after npm install -g git-truck@latest, and it is MIT licensed (GitHub).
Pick Git Truck if you want to explore authorship visually in a browser, for example in a retrospective.
CodeScene
CodeScene tracks knowledge distribution and can simulate a key person leaving. Its docs describe a dashboard for key-personnel distribution and low code familiarity, and an off-boarding simulation that flags low bus factor areas (CodeScene docs).
Pick CodeScene if engineering management wants a supported commercial dashboard. See repowise vs CodeScene.
repowise ownership
repowise computes owners, bus factor, fading ownership and suggested reviewers from git blame and history. It runs offline with no LLM, and the same data reaches coding agents through its MCP tools, so an agent can ask who owns a file before editing it. Ownership sits next to hotspots and bug history in the git intelligence view.
uv tool install repowise
repowise init
The engine is open source under AGPL-3.0 and self-hostable; hosted workspaces add team views across repositories. For a worked example on a real project, read one maintainer, one bus factor.
Pick repowise if you want ownership tied to hotspots, risk and reviewer suggestions, available to agents too.
How to choose
- Quick audit of one repo: git-fame, then Git Truck to look at the hot spots.
- Review routing and compliance: CODEOWNERS, reviewed against actual history each quarter.
- Engineering manager, many teams: CodeScene or repowise workspaces for key-person risk across repositories.
- Enterprise or air-gapped: self-host repowise; nothing leaves the network.
- Agents editing code: use a tool exposed over MCP so the agent sees owners before it edits.
FAQ
- What is a bus factor tool?
- A bus factor tool measures how concentrated knowledge of the code is, usually the number of people who wrote most of it. It reads git history, since the answer is about who actually did the work.
- How do I calculate bus factor from git?
- Count how many authors account for most of the surviving lines or recent changes in a file or repository; if one author does, the bus factor is one. repowise reports this per file and per repo from
git blame. - What is the difference between CODEOWNERS and actual ownership?
- CODEOWNERS lists who is declared responsible for review. Actual ownership is who has written and changed the code, found only in git history.
- Is there a free tool for code ownership analysis?
- Yes. git-fame and Git Truck are open source, and the repowise CLI is free under AGPL-3.0.
- Can an AI agent see code ownership?
- Yes, if the tool exposes it. repowise serves owners and suggested reviewers through its MCP tools.