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pyscn

A structural static analyzer for Python. Detects dead code, duplication, complexity, and coupling issues via control-flow and tree analysis.

uvx pyscn@latest analyze .

Features

  • 32 rules across unreachable code, duplicate code, complexity, class design, dependency injection, module structure, and mock data.
  • CFG-based reachability finds dead code past return / raise / break / continue and unreachable branches.
  • APTED + LSH clone detection across four clone types (identical, renamed, modified, semantic).
  • CBO / LCOM4 class coupling and cohesion metrics.
  • Circular import detection via Tarjan's SCC.
  • Health score (0–100) with per-category breakdown.
  • CI-ready with pyscn check, linter-style output, and deterministic exit codes.
  • MCP server (pyscn-mcp) for Claude Code, Cursor, and other MCP clients.

Written in Go. 100,000+ lines/sec on typical hardware. No Python runtime dependencies.

Installation

uvx pyscn@latest <command>   # run without installing (recommended)
uv tool install pyscn        # install with uv
pipx install pyscn           # install with pipx
pip install pyscn            # install with pip

See Installation for all options.

Quick start

pyscn analyze .                         # full analysis, HTML report
pyscn check --select complexity,deadcode src/   # CI gate
pyscn init                              # generate .pyscn.toml

See Quick Start and the Rule catalog.