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Lint Rules

marimo includes a comprehensive linting system that helps you write better, more reliable notebooks. The linter checks for various issues that could prevent your notebook from running correctly or cause confusion.

How to Use

You can run the linter using the CLI:

# Check all notebooks in current directory
marimo check .

# Check specific files
marimo check notebook1.py notebook2.py

# Auto-fix fixable issues
marimo check --fix .

Rule Categories

marimo's lint rules are organized into three main categories based on their severity:

🚨 Breaking Rules

These errors prevent notebook execution.

Code Name Description Fixable
MB001 unparsable-cells Cell contains unparsable code ❌
MB002 multiple-definitions Multiple cells define the same variable ❌
MB003 cycle-dependencies Cells have circular dependencies ❌
MB004 setup-cell-dependencies Setup cell cannot have dependencies ❌

✨ Formatting Rules

These are style and formatting issues.

Code Name Description Fixable
MF001 general-formatting General formatting issues with the notebook format. 🛠️
MF002 parse-stdout Parse captured stdout during notebook loading ❌
MF003 parse-stderr Parse captured stderr during notebook loading ❌

Legend

  • 🛠️ = Automatically fixable with marimo check --fix
  • ❌ = Not automatically fixable

Configuration

Most lint rules are enabled by default. You can configure the linter behavior through marimo's configuration system.