> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/provablehq/leo/llms.txt
> Use this file to discover all available pages before exploring further.

# leo fmt

> Format Leo source files

Automatically format Leo source files according to the official Leo style guide. This command ensures consistent code formatting across your project.

## Usage

```bash theme={null}
leo fmt [OPTIONS]
```

## Options

<ParamField path="--check" type="boolean">
  Check if files are formatted without making changes. Exit with code 1 if any files need formatting.
</ParamField>

<ParamField path="--path" type="string">
  Specific file or directory to format. Defaults to current directory.
</ParamField>

## Examples

### Format all files in project

```bash theme={null}
leo fmt
```

### Check formatting without changes

```bash theme={null}
leo fmt --check
```

This is useful in CI/CD pipelines:

```bash theme={null}
# In CI script
leo fmt --check || exit 1
```

### Format specific file

```bash theme={null}
leo fmt --path src/main.leo
```

### Format specific directory

```bash theme={null}
leo fmt --path src/
```

## Formatting Rules

Leo follows these formatting conventions:

### Indentation

* Use 4 spaces for indentation
* No tabs

### Line Length

* Maximum 120 characters per line
* Break long lines at logical points

### Spacing

```leo theme={null}
// Correct spacing around operators
let sum: u32 = a + b;

// Spacing in function calls
let result: u32 = compute(x, y, z);

// No trailing whitespace
```

### Function Declarations

```leo theme={null}
// Properly formatted function
fn transfer(
    sender: address,
    receiver: address,
    amount: u64
) -> bool {
    return true;
}
```

### Imports

```leo theme={null}
// Group imports at the top
import token.aleo;
import utilities.aleo;
```

## Integration

### Pre-commit Hook

Add to `.git/hooks/pre-commit`:

```bash theme={null}
#!/bin/bash
leo fmt --check
if [ $? -ne 0 ]; then
    echo "Code is not formatted. Run 'leo fmt' to format."
    exit 1
fi
```

### VS Code

Configure VS Code to format on save by adding to `.vscode/settings.json`:

```json theme={null}
{
  "leo.formatOnSave": true
}
```

## CI/CD Integration

Add formatting check to your CI pipeline:

```yaml theme={null}
# GitHub Actions example
- name: Check formatting
  run: leo fmt --check
```

## Related Commands

* [Build](/cli/build) - Compile your formatted code
* [Test](/cli/test) - Run tests on formatted code

## Best Practices

<Tip>
  Run `leo fmt` before committing code to maintain consistent style across the team.
</Tip>

<Note>
  The formatter preserves comments and applies minimal changes to maintain code readability.
</Note>

## Troubleshooting

### Format check fails in CI

If `leo fmt --check` fails in CI, run locally:

```bash theme={null}
leo fmt
git add .
git commit -m "Format code"
```

### Syntax errors prevent formatting

Fix syntax errors before formatting:

```bash theme={null}
leo build  # Check for syntax errors
leo fmt    # Format after fixing errors
```