fallow: codebase intelligence for TypeScript and JavaScript

Agent skills give AI coding agents structured knowledge about how to use fallow. Skills cover when to run each command, what flags to use, how to read the output, and how to avoid common pitfalls. Instead of relying on the agent’s general knowledge, skills provide precise, up-to-date instructions for codebase health, cleanup analysis, circular dependency detection, duplication, and complexity hotspots.

Skills work alongside the CLI and MCP integrations. They tell agents how to use fallow effectively, while the CLI and MCP provide the tools to do it.

What’s included

The fallow-skills package includes:

Component	Description
Analysis skill	Workflows for unused code, duplication, complexity, boundary analysis, auto-fix, and CI setup
CLI reference	Complete command specs, flags, output formats, and configuration
Gotchas	Common pitfalls with correct vs. incorrect examples (e.g., `fix --yes` in non-TTY)
Workflow patterns	Recipes for CI pipelines, monorepo analysis, migrating from knip/jscpd, and incremental adoption

Installation

/plugin marketplace add fallow-rs/fallow-skills
/plugin install fallow-skills@fallow-rs/fallow-skills

git clone https://github.com/fallow-rs/fallow-skills.git ~/.cursor/skills/fallow-skills

git clone https://github.com/fallow-rs/fallow-skills.git ~/.agents/skills/fallow-skills

git clone https://github.com/fallow-rs/fallow-skills.git ~/.codeium/windsurf/skills/fallow-skills

git clone https://github.com/fallow-rs/fallow-skills.git .github/skills/fallow-skills

gemini skills install https://github.com/fallow-rs/fallow-skills.git

git clone https://github.com/fallow-rs/fallow-skills.git ~/.config/agents/skills/fallow-skills

Skills follow the open Agent Skills specification and work with any compatible agent.

What agents can do after installation

Once installed, agents know how to respond to natural language requests like these:

Find cleanup opportunities

“Find all unused exports in this project”. Agent runs fallow dead-code --format json --quiet --unused-exports and summarizes findings.

Clean up dependencies

“Are there any unused dependencies?” Agent runs targeted analysis and suggests removals.

Detect duplication

“Find code duplication in the codebase”. Agent runs fallow dupes with the right mode and interprets clone families.

Auto-fix

“Remove unused exports”. Agent runs dry-run first, shows proposed changes, then applies with --yes.

CI setup

“Set up a code quality gate in CI”. Agent generates the correct GitHub Actions workflow with baselines.

Debug false positives

“Why is this export flagged?” Agent uses --trace to investigate and suggests suppression if needed.

Workflow recipe: adopt Fallow in an existing repo

When the goal is to bring an existing codebase to a clean Fallow policy (not just audit a single PR), fallow’s approach is to hand the cleanup work to the agent: fallow finds the problems, the agent fixes them in code. Three ways to run this, pick whichever your agent supports:

Install the skill (best). fallow-skills ships the full adoption workflow. Once installed, the agent does not need to fetch docs URLs during use. Installation is one line per agent, above.
Add the MCP server. Combine with the skill or use standalone. The agent gets audit, dead_code, dupes, and health as structured tools with _meta explanations on every finding. See MCP.
Paste the prompt below. Self-contained fallback for agents without skill or MCP support, or for sandboxed agents that cannot fetch URLs.

Copy-paste adoption prompt (self-contained)

Adopt Fallow in this repository.

Goal:
- use full-repo analysis first (`fallow`, `fallow dead-code`, `fallow dupes`, `fallow health`), not `fallow audit`
- fix real dead code, duplication, and complexity issues in code
- model intentional exceptions with the narrowest correct mechanism
- end with no functions above the repo's chosen health thresholds, or a consciously widened threshold with written justification
- then set up `fallow audit` as a PR gate

Process:
1. Run `npx fallow`, then `npx fallow dead-code`, `npx fallow dupes`, and `npx fallow health`. Use `--format json` for structured output.
2. If no config exists, run `fallow init` and create a minimal repo policy.
3. Fix high-confidence issues first:
   - unresolved imports
   - unlisted dependencies
   - unused files (sanity-check with `fallow list --entry-points`)
   - unused dependencies
4. For each remaining finding, choose one path:
   - fix it in code (preferred)
   - model it in config
   - add a narrow inline exception only if it is truly one-off
5. Match reasons to mechanisms:
   - external API: `@public` / `@internal` / `@beta` / `@alpha` JSDoc tags, or `publicPackages`
   - runtime or framework entry point: `entry`, `dynamicallyLoaded`, plugin-aware config
   - generated code: `ignorePatterns`, `health.ignore`
   - intentionally retained dependency: `ignoreDependencies`
   - intentional unused export: `@expected-unused` (preferred over inline comments because it self-cleans)
   - one-off false positive: `fallow-ignore-next-line`
   - repo-wide policy: `rules`, `health`, duplication settings, `overrides`
6. Prefer config-level modeling over repeated suppression.
7. Keep every exception narrow and explain why it exists in a commit message.
8. Re-run Fallow after each batch until the repo is clean under the chosen policy.
9. Only after repo cleanup, run `npx fallow audit` and wire it into CI.

At the end, report:
- code changes
- config changes
- exceptions added and why
- anything left
- the final commands and outputs that show the repo is clean

Skills vs MCP vs CLI

	Skills	MCP	CLI
What it provides	Knowledge about how to use fallow	Structured tool interface	Direct command execution
Setup	One-time install per agent	MCP server configuration	fallow binary in PATH
Agent support	Any agent with skill support	Agents with MCP support	Any agent that runs shell commands
Best for	Teaching agents fallow best practices	Typed tool calling in agent frameworks	Universal compatibility

For the best experience, combine all three. Install the skill for knowledge, configure MCP for structured tool calling, and keep fallow in PATH for CLI fallback.

Agent integration

CLI and MCP integration for AI agents.

CI integration

Catch codebase issues in your CI pipeline.

VS Code extension

Real-time feedback for human developers.

Getting Started

Analysis

Cloud

Configuration

Integrations

Explanations

Frameworks

Migration

Agent Skills

What’s included

Installation

What agents can do after installation

Find cleanup opportunities

Clean up dependencies

Detect duplication

Auto-fix

CI setup

Debug false positives

Workflow recipe: adopt Fallow in an existing repo

Skills vs MCP vs CLI

See also

Agent integration

CI integration

VS Code extension

​What’s included

​Installation

​What agents can do after installation

Find cleanup opportunities

Clean up dependencies

Detect duplication

Auto-fix

CI setup

Debug false positives

​Workflow recipe: adopt Fallow in an existing repo

​Skills vs MCP vs CLI

​See also

Agent integration

CI integration

VS Code extension

What’s included

Installation

What agents can do after installation

Workflow recipe: adopt Fallow in an existing repo

Skills vs MCP vs CLI

See also