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@fallow-rs

fallow

Codebase intelligence for TypeScript and JavaScript. Free static analysis, optional paid runtime intelligence (Fallow Runtime). Rust-native, 90 plugins.
README.md

fallow

Codebase intelligence for TypeScript and JavaScript.
Free static analysis. Optional paid runtime intelligence.

Documentation Website npm crates.io

Linters check files. TypeScript checks types. Fallow checks the codebase.

Fallow builds a module graph across your TypeScript and JavaScript project and reports what nothing depends on, what runs in cycles, what's duplicated, what's complex, and (with the optional runtime layer) what actually ran in production. One pipeline, two layers, zero configuration on the free side.

Two layers, one decision system

  • Static intelligence (free, MIT). Unused files, exports, types, dependencies, circular imports, code duplication, complexity hotspots, architecture boundaries, feature-flag usage. Rust-native, sub-second on most projects, 90 framework plugins, JSON / SARIF / CodeClimate / markdown outputs, CI + editor + MCP integrations.
  • Runtime intelligence (paid, Fallow Runtime). Production execution evidence merged into the same fallow health report. Hot paths, cold paths, runtime-backed deletion confidence, runtime-weighted health, stale-flag evidence, trends, alerts, and shared team workflows.

Static analysis is free and open source. Runtime intelligence is the paid team layer.

Start here

npx fallow

Repositories

Repo What it is
fallow The CLI, LSP, MCP server, GitHub Action, and VS Code extension. Rust-native, MIT.
docs docs.fallow.tools (Mintlify).
fallow-skills Agent Skills pack for Claude Code, Cursor, Codex, Gemini CLI, Copilot, Windsurf, Amp, and 30+ more.
fallow-cov-protocol Wire contract between the fallow CLI and Fallow Runtime's production-coverage sidecar.
oxc-coverage-instrument Istanbul-compatible coverage instrumentation on the Oxc AST. Powers browser coverage collection.

Outcomes

  • Delete cold code with runtime-backed confidence, not guesses.
  • Review hot-path changes with evidence, not reviewer instinct.
  • Prioritize refactors by traffic and complexity together.
  • Retire stale flags from what ran in practice, not what's written.

Contributing

Issues and PRs welcome across every repo in the org. Start with the main fallow issue tracker or check discussions.

Popular repositories Loading

  1. fallow fallow Public

    Codebase intelligence for TypeScript and JavaScript. Free static layer: unused code, duplication, circular deps, complexity hotspots, architecture boundaries. Optional paid runtime layer: hot-path …

    Rust 469 13

  2. fallow-skills fallow-skills Public

    Agent skills for fallow, codebase intelligence for JavaScript and TypeScript. Teaches AI agents how to find unused code, duplication, circular deps, complexity hotspots, architecture drift, and (wi…

    16 1

  3. oxc-coverage-instrument oxc-coverage-instrument Public

    Istanbul-compatible JavaScript/TypeScript coverage instrumentation using the Oxc AST

    Rust 15

  4. srcmap srcmap Public

    The source map SDK for Rust tooling. Parse, generate, remap, and compose — with full ECMA-426 compliance.

    Rust 3

  5. docs docs Public

    Documentation for fallow, codebase intelligence for TypeScript and JavaScript. docs.fallow.tools

    MDX

  6. fallow-cov-protocol fallow-cov-protocol Public

    Versioned JSON envelope types shared between the fallow CLI and the fallow-cov production-coverage sidecar.

    Rust

Repositories

Showing 7 of 7 repositories
  • fallow Public

    Codebase intelligence for TypeScript and JavaScript. Free static layer: unused code, duplication, circular deps, complexity hotspots, architecture boundaries. Optional paid runtime layer: hot-path review and cold-path deletion evidence from real production traffic. Rust-native, sub-second, 90 framework plugins.

    fallow-rs/fallow’s past year of commit activity
    Rust 469 MIT 13 3 1 Updated Apr 20, 2026
  • docs Public

    Documentation for fallow, codebase intelligence for TypeScript and JavaScript. docs.fallow.tools

    fallow-rs/docs’s past year of commit activity
    MDX 0 MIT 0 0 0 Updated Apr 20, 2026
  • fallow-skills Public

    Agent skills for fallow, codebase intelligence for JavaScript and TypeScript. Teaches AI agents how to find unused code, duplication, circular deps, complexity hotspots, architecture drift, and (with Fallow Runtime) hot-path and cold-path evidence. Works with Claude Code, Cursor, Codex, Gemini CLI, and 30+ agents.

    fallow-rs/fallow-skills’s past year of commit activity
    16 MIT 1 0 0 Updated Apr 20, 2026
  • fallow-cov-protocol Public

    Versioned JSON envelope types shared between the fallow CLI and the fallow-cov production-coverage sidecar.

    fallow-rs/fallow-cov-protocol’s past year of commit activity
    Rust 0 0 0 0 Updated Apr 20, 2026
  • .github Public

    Community files and org profile for fallow-rs

    fallow-rs/.github’s past year of commit activity
    0 0 0 0 Updated Apr 20, 2026
  • srcmap Public

    The source map SDK for Rust tooling. Parse, generate, remap, and compose — with full ECMA-426 compliance.

    fallow-rs/srcmap’s past year of commit activity
    Rust 3 MIT 0 0 13 Updated Apr 19, 2026
  • oxc-coverage-instrument Public

    Istanbul-compatible JavaScript/TypeScript coverage instrumentation using the Oxc AST

    fallow-rs/oxc-coverage-instrument’s past year of commit activity
    Rust 15 MIT 0 0 0 Updated Apr 17, 2026

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