gemini-cli

# Gemini CLI Usage Guide

This skill ensures clean, readable Gemini CLI invocations without shell gymnastics.

## Core Principle

**Always pipe content via stdin. Never use heredocs or shell variable assignment.**

```bash
# GOOD - Clean and readable
cat file.md | gemini --sandbox -o text "Review this for issues"

# BAD - Shell gymnastics
CONTENT=$(cat file.md)
gemini --sandbox "$(cat <<'EOF'
Review this:
$CONTENT
EOF
)"
```

## Command Structure

```bash
# Pipe content via stdin
<content-source> | gemini [options] "prompt"

# Or use @ to reference files/folders directly
gemini [options] "prompt" @file.py @folder/
```

### Required Options

| Option | Purpose |
|--------|---------|
| `--sandbox` or `-s` | Always use - prevents code modifications |
| `-o text` or `--output-format text` | Plain text output |
| `-m MODEL` or `--model MODEL` | Model selection |

### Available Models

| Model | Use Case |
|-------|----------|
| `gemini-3-pro-preview` | Default, best quality |
| `gemini-3-flash-preview` | Faster, cheaper |

## Common Patterns

### Using @ to Reference Files/Folders

The `@` syntax lets you reference files and folders directly without piping:

```bash
# Single file
gemini --sandbox -o text "Review this code" @src/module.py

# Multiple files
gemini --sandbox -o text "Check consistency between these" @src/models.py @src/views.py

# Entire folder
gemini --sandbox -o text "Review this module" @src/auth/

# Mix files and folders
gemini --sandbox -o text "Review the API implementation" @src/api/ @tests/test_api.py
```

### Review a Plan/Spec File

```bash
# Using stdin pipe
cat plans/my-feature.md | gemini --sandbox -o text -m gemini-3-pro-preview \
  "Review this plan for architectural issues, missing requirements, and risks"

# Using @ syntax
gemini --sandbox -o text "Review this plan for issues" @plans/my-feature.md
```

### Review Git Diff

```bash
# Unstaged changes
git diff | gemini --sandbox -o text "Review this diff for bugs and security issues"

# Stage