Early accessOpen source · MIT · Any language

Ship refactors with
proof, not vibes.

Your codebase has features no one mapped. Faultlines reads git history and shows which ones are rotting — ranked by bug density, churn, and bus factor. No Jira. No tagging. One command.

$pip install faultlines
Your code stays on your machine. The AI sees only file paths and git metadata.
We'll run a full AI-powered scan on your repo and email you the feature map + health report. No API key needed — we cover the cost. ★ star on GitHub
12
OSS repos scanned
70–100%
feature accuracy
0
Jira tags required
Any
Language
Live scan preview

Point at a repo.
See the data.

One command reads your git history, clusters files into a draft feature map, and produces a health report. No Jira, no tagging, no setup — the rough cut is ready in minutes, and you refine the names and groupings from there.

~/cal.com — faultlines analyze
Live
$faultlines analyze . --llm --flows
→ Detected monorepo ((pnpm workspace, 20 packages))
→ Reading git blame 10,142 files · 84,391 commits
→ Clustering with Claude Sonnet 4.6 ✓
→ Scoring features ✓
●featurehealthtestsbug%commitsimpact
●web/settingsapps/web/components23—70%206high
manage-organization-roles-flow11—81%37
manage-oauth-clients-flow15—77%13
manage-out-of-office-flow21—71%14
●trpc/viewerpackages/trpc/server26—68%539medium
●web/bookingsapps/web/modules16—76%172high
●prismapackages/prisma/selects47—56%220low
●web/dashboardapps/web/pages27—67%175medium
●lib/serverpackages/lib/server34—63%177medium
✓ Wrote ~/.faultlines/feature-map-calcom.json (282 features, 725 flows)
elapsed 23m 34s · cost $2.14 · top 6 of 282 shown
Real run on cal.com — TS monorepo · pnpm workspace · 20 packages. Reproduce yourself with pip install faultlines.
Benchmarked

Run it yourself on real code.

Don't trust a marketing number. These are public OSS repos you can clone and scan today — we did the run, the output is byte-for-byte reproducible with the CLI.

We draft a feature map from git history alone. On the repos below, we found 70–100% of the modules a maintainer would list in their README — with real business names, not src/ or utils/. You refine the names, merge or split features, and get a health report instantly.

gin-gonic/ginGo
HTTP web framework — router, middleware, binding, render, context.
files 130features 22flows 36
axios/axiosJS
HTTP client — adapters, interceptors, cancel tokens, transforms, defaults.
files 329features 57flows 0
tiangolo/fastapiPython
Web framework — routing, dependencies, security, openapi, websockets, exceptions.
files 2,981features 14flows 0
pallets/flaskPython
Micro web framework — app, blueprints, sessions, templating, json, cli.
files 236features 8flows 0
trpc/trpcTS
End-to-end typesafe APIs — server, client, react-query, openapi, adapters, links.
files 1,573features 16flows 48
excalidraw/excalidrawTS app
Virtual whiteboard — canvas renderer, drawing tools, data export, collaboration.
files 1,225features 15flows 62
outline/outlineTS app
Team wiki — rich-text editor, document management, plugins, dashboard.
files 2,390features 22flows 188
formbricks/formbricksTS app
Open-source form builder — surveys, responses, organization, auth.
files 3,316features 33flows 136
makeplane/planeTS app
Jira alternative — issues, projects, pages, workspaces, editor, inbox.
files 4,932features 134flows 408
documenso/documensoTS app
DocuSign alternative — document-signing, editor, templates, auth, billing, webhooks.
files 2,530features 49flows 191
TryGhost/GhostTS/JS app
Blogging & newsletter platform — members, email, admin, posts, stats.
files 6,898features 101flows 281
calcom/cal.comTS app
Scheduling platform — bookings, events, availability, teams, app-store, insights.
files 10,463features 282flows 725
Reproduce any of these with faultlines analyze /path/to/repo --llm --flows. Snapshots live in tests/baseline/accuracy-7repos.

Three commands. No setup.

No tagging, no ticket hygiene, no cross-team alignment meeting. Just a CLI.

1
Install
Python package. Works locally, in CI, or via GitHub App.
pip install faultlines
2
Analyze
Claude (or local Ollama) reads git blame and commit history, clusters files into features.
faultlines analyze .
3
Refactor with receipts
Open the report. Show leadership exactly where the bugs live and why it's worth fixing.
~/.faultlines/*.json
Roadmap

Built. Building. Next.

Where Faultlines is today, and where it's heading.

Live
Shipping now
Open-source CLI. Install it and scan any repo today.
  • Feature & flow detectionLLM clusters files into features and user-facing flows from git history
  • Health scoring0–100 score combining bug ratio, churn, and bus factor
  • Monorepo supportpnpm, Turbo, Nx, Lerna, Cargo, Go workspaces
  • Local-first LLMClaude or Ollama — code never leaves your laptop
Private beta
Hosted dashboard
SaaS on top of the CLI. Team view, trends, alerts.
  • PR risk commentsBot annotates every PR with affected features and their health
  • Health trends over timeWatch features rot or recover sprint by sprint
  • Bus-factor alertsGet pinged when a critical feature has only one owner left
  • GitHub App + SSOOne-click install, auto-scan on push, GitHub/Google OAuth
Want early access to the hosted dashboard? Join the waitlist ↓

Your next refactor decision —
backed by data.

Drop your repo URL — we'll scan it with Claude Sonnet and email you a feature map with health scores. Free, no API key needed.

Free scan — we cover the LLM cost. Public repos only.