Supercov
Open-source code coverage tool for teams using coding agents, and a self-hosted Codecov alternative. Reports line, branch, and MC/DC coverage plus AI quality and security checks in pull requests.
Overview
Description
Supercov is an open-source, MIT-licensed code coverage tool built for teams that work with coding agents, and a self-hosted alternative to Codecov. It wraps the test command your project already uses and reports line, branch, and MC/DC coverage, which test covers each line, and which code no assertion actually checks, so an agent knows exactly what to test or refactor next. Reports stay on your machine or in your own CI.
Features
- Deep Coverage Metrics: Line, branch, and MC/DC coverage file by file, with each uncovered path turned into a small, actionable target.
- Per-Test Coverage: Shows which test runs each line for Playwright, Vitest, Jest, cargo test, RSpec, and more.
- Assertion Coverage: Finds code that tests execute but never check, without running mutation testing.
- Quality & Security Scoring: Scores each file, ranks the weakest for refactoring, and flags risky lines across twelve security checks.
- Portable HTML Report: One interactive, self-contained file you can attach to a pull request, with no server or account.
- Pull Request Comments: A GitHub Action comments on changed lines no test ran and can fail the job below a coverage floor.
Technology Stack
A single native binary written in Rust, distributed through npm, PyPI, RubyGems, crates.io, Go, and Homebrew. Supports JavaScript, TypeScript, Python, Ruby, Rust, Go, Java, and Kotlin, and installs as a plugin for Claude Code, Codex, and Gemini CLI.
Requirements
Linux, macOS, or Windows (x64 or arm64) and your project's own test command. Coverage needs no account; assertion coverage and the quality and security checks require a TypeSafe AI API key (about a cent per megabyte of source).
