undermybelt repo-scan
Every ecosystem has its own dependency manager, but no tool looks across C++, Android, iOS, and Web to tell you: how much code is actually yours, what's third-party, and what's dead weight.
When to Use
- Taking over a large legacy codebase and need a structural overview
- Before major refactoring — identify what's core, what's duplicate, what's dead
- Auditing third-party dependencies embedded directly in source (not declared in package managers)
- Preparing architecture decision records for monorepo reorganization
Installation
# Fetch only the pinned commit for reproducibility
mkdir -p ~/.claude/skills/repo-scan
git init repo-scan
cd repo-scan
git remote add origin https://github.com/haibindev/repo-scan.git
git fetch --depth 1 origin 2742664
git checkout --detach FETCH_HEAD
cp -r . ~/.claude/skills/repo-scan
Review the source before installing any agent skill.
Core Capabilities
| Capability | Description |
|---|---|
| Cross-stack scanning | C/C++, Java/Android, iOS (OC/Swift), Web (TS/JS/Vue) in one pass |
| File classification | Every file tagged as project code, third-party, or build artifact |
| Library detection | 50+ known libraries (FFmpeg, Boost, OpenSSL…) with version extraction |
| Four-level verdicts | Core Asset / Extract & Merge / Rebuild / Deprecate |
| HTML reports | Interactive dark-theme pages with drill-down navigation |
| Monorepo support | Hierarchical scanning with summary + sub-project reports |
Analysis Depth Levels
| Level | Files Read | Use Case |
|---|---|---|
fast |
1-2 per module | Quick inventory of huge directories |
standard |
2-5 per module | Default audit with full dependency + architecture checks |
deep |
5-10 per module | Adds thread safety, memory management, API consistency |
full |
All files | Pre-merge comprehensive review |
How It Works
- Classify the repo surface: enumerate files, then tag each as project code, embedded third-party code, or build artifact.
- Detect embedded libraries: inspect directory names, headers, license files, and version markers to identify bundled dependencies and likely versions.
- Score each module: group files by module or subsystem, then assign one of the four verdicts based on ownership, duplication, and maintenance cost.
- Highlight structural risks: call out dead-weight artifacts, duplicated wrappers, outdated vendored code, and modules that should be extracted, rebuilt, or deprecated.
- Produce the report: return a concise summary plus the interactive HTML output with per-module drill-down so the audit can be reviewed asynchronously.
Examples
On a 50,000-file C++ monorepo:
- Found FFmpeg 2.x (2015 vintage) still in production
- Discovered the same SDK wrapper duplicated 3 times
- Identified 636 MB of committed Debug/ipch/obj build artifacts
- Classified: 3 MB project code vs 596 MB third-party
Best Practices
- Start with
standarddepth for first-time audits - Use
fastfor monorepos with 100+ modules to get a quick inventory - Run
deepincrementally on modules flagged for refactoring - Review the cross-module analysis for duplicate detection across sub-projects