Ratchets: Progressive lint enforcement for human and AI developers

Ratchets is a progressive lint enforcement tool that allows codebases to contain existing violations while preventing new ones. Unlike traditional linters that enforce binary pass/fail, Ratchets permits a budgeted number of violations per rule per region. These budgets can only decrease over time (the "ratchet" mechanism), ensuring technical debt monotonically decreases.

Key Features

• Progressive enforcement: Allow existing violations while preventing new ones
• Region-based budgets: Set different limits for different parts of your codebase
• Regex and AST rules: Match patterns via text or tree-sitter queries
• Agent-friendly: JSONL output, deterministic results, clear exit codes
• Fast: Parallel execution, lazy parser loading, Rust performance

Installation

Install from Github

Install from source using the installation script:

curl -sSf https://raw.githubusercontent.com/imbue-ai/ratchets/main/install.sh | sh

This will automatically build and install ratchets to ~/.cargo/bin/. Requires Rust/Cargo to be installed.

Quick Start

Initialize Ratchets in your repository:

ratchets init

This creates:

• ratchets.toml — Configuration file
• ratchet-counts.toml — Violation budgets
• ratchets/ — Directory for custom rules

Optionally, drop a .ratchetignore file at any depth in the tree to exclude paths from ratchet enforcement. Syntax matches .gitignore (per-directory, nested files compose, negation supported with !); these files are checked in alongside source.

Run checks:

ratchets check

Usage

ratchets check

Verify that violations are within budget:

ratchets check                    # Check all files
ratchets check --format jsonl     # Machine-readable output
ratchets check src/               # Check specific path
ratchets check --since main       # Only files changed since the `main` ref

--since <REF> shells out to git diff <REF> --name-only and intersects the result with the file walker's output. Include/exclude/gitignore filters still apply, and files deleted relative to <REF> are skipped silently. The command exits with code 2 if <REF> is unknown or the current directory is not inside a git repository.

ratchets bump

Increase the violation budget (requires justification in commit message):

ratchets bump no-unwrap --region src/legacy --count 20
ratchets bump no-unwrap --region src/legacy  # Auto-detect current count

ratchets tighten

Reduce budgets to match current violation counts:

ratchets tighten                    # Tighten all rules
ratchets tighten no-unwrap          # Tighten specific rule
ratchets tighten --region src/      # Tighten specific region

ratchets list

List all enabled rules and their status:

ratchets list
ratchets list --format jsonl

Configuration

ratchets.toml

Ratchets uses an explicit opt-in model: rules only fire when listed in enabled_ratchets (directly or via a $set-name reference). Anything in disabled_ratchets is subtracted from the resolved enabled set — disabled always wins.

enabled_ratchets = ["$common-starter", "no-unwrap"]
disabled_ratchets = ["no-fixme-comments"]

[ratchets]
version = "2"
languages = ["rust", "typescript"]
include = ["src/**", "tests/**"]
exclude = ["**/generated/**"]

# Optional per-rule settings (severity, regions). Entries here do NOT
# enable rules; enablement is governed by enabled_ratchets above.
[rules]
no-todo-comments = { severity = "warning" }

[output]
format = "human"

Reference syntax

• "rule-id" — enables (or disables) a single rule by ID.
• "$set-name" — references a ratchet-set: a curated bundle of rule IDs. Sets can compose other sets via $other-set inside their own rules array; cycle-aware resolution catches accidental loops.
• The @ sigil is unchanged — it still refers to entries in the existing [patterns] table for glob references.

Shipped ratchet-sets

This binary ships a single starter set:

• $common-starter — the language-agnostic curated default. Today's members: no-todo-comments, no-fixme-comments. Membership criterion ("stable, broadly applicable, no framework-specific opinions") is documented at the top of builtin-ratchets/sets/common-starter.toml.

Per-language starter sets ($python-starter, $rust-starter, $typescript-starter) will land in follow-up MRs — their curation is its own review topic.

User-defined ratchet-sets

Drop your own set files under ratchets/sets/*.toml. User-defined sets override embedded sets with the same ID, mirroring how ratchets/regex/ and ratchets/ast/ override embedded rules. A set file looks like:

[set]
id = "house-style"
description = "Rules that match our coding conventions"
rules = ["$common-starter", "no-unwrap"]

enabled_ratchets = ["$house-style"] then enables the union.

ratchet-counts.toml

[no-unwrap]
"." = 0
"src/legacy" = 15
"tests" = 50

[no-todo-comments]
"src" = 23

Regions are explicitly configured directory paths. Files in unconfigured subdirectories count toward their nearest configured parent region. Regions are scoped per-rule.

Counts for rules no longer in the resolved enabled set are kept dormant (no cleanup). ratchets tighten emits a stderr warning naming each orphan so you can re-enable the rule later without losing the count.

Git Integration

Merge Driver

Ratchets provides a merge driver that resolves conflicts by taking the minimum count:

# .gitattributes
ratchet-counts.toml merge=ratchets

# .git/config
[merge "ratchets"]
    name = Ratchets counts merge driver (minimum wins)
    driver = ratchets merge-driver %O %A %B

Pre-commit Hook

#!/bin/sh
ratchets check || exit 1

Exit Codes

Code	Meaning
0	All rules within budget
1	At least one rule exceeded budget
2	Configuration or usage error
3	Parse error in source file

Documentation

• DESIGN.md — Design specification and rationale
• ARCHITECTURE.md — Implementation architecture

Further Reading

The ratchet concept was originally described by qntm: https://qntm.org/ratchet