MB004: setup-cell-dependencies

🚨 Breaking ❌ Not Fixable

MB004: Setup cell cannot have dependencies.

What it does

Validates that the setup cell (if present) does not depend on variables defined in other cells, ensuring proper execution order.

Why is this bad?

Setup cell dependencies break marimo's execution model because:

• The setup cell must run first to initialize the notebook
• Dependencies on other cells would create impossible execution order
• It violates the setup cell's purpose as initialization code

This is a breaking error because it makes the notebook non-executable.

Examples

Problematic:

# Setup cell
y = x + 1  # Error: setup depends on other cells

# Cell 1
x = 1

Solution:

# Setup cell
y = 1  # Setup defines its own variables

# Cell 1
x = y + 1  # Other cells can use setup variables

References

• Setup References Guide
• Understanding Errors