cursor-tab-completion

# Cursor Tab Completion

Master Cursor's AI-powered Tab completion system. Tab uses a specialized Cursor model trained for inline code prediction -- it learns from your accept/reject behavior to improve over time.

## How Tab Works

1. You type code in the editor
2. Cursor's model predicts what comes next based on: current file, open tabs, recent edits, project rules
3. Ghost text (gray text) appears inline
4. You decide: **Tab** to accept, **Esc** to dismiss

```
// You type:
function validateEmail(email: string)

// Ghost text appears:
function validateEmail(email: string): boolean {
  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;    ← gray ghost text
  return emailRegex.test(email);
}
```

## Key Bindings

| Action | macOS | Windows/Linux |
|--------|-------|---------------|
| Accept full suggestion | `Tab` | `Tab` |
| Accept word-by-word | `Cmd+→` | `Ctrl+→` |
| Dismiss suggestion | `Esc` | `Esc` |
| Force trigger | `Ctrl+Space` | `Ctrl+Space` |

**Word-by-word acceptance** (`Cmd+→`) is powerful for partial suggestions. If the AI suggests a complete function but you only want the signature, accept word-by-word until you have what you need, then type your own body.

## Tab Completion Settings

Access via `Cursor Settings` > `Tab`:

| Setting | Purpose | Recommendation |
|---------|---------|----------------|
| Tab Completion | Master on/off toggle | Keep enabled |
| Trigger in comments | Generate comment text | Disable for less noise |
| Accept suggestion keybinding | Remap Tab to another key | Default (Tab) works best |
| Suggestion delay | Time before ghost text appears | Lower = faster but more flicker |

### Disabling Tab for Comments

If Tab suggestions in comments are distracting:

`Cursor Settings` > `Tab Completion` > uncheck `Trigger in comments`

## Context That Improves Completions

Tab quality depends heavily on available context:

1. **Current file**: The model reads the full file you are editing
2. **Open editor tabs**: Files open in other tabs provide pattern context
3. **Recent edits**: Changes you have made in the last few minutes
4. **Project rules**: `.cursor/rules/*.mdc` or `.cursorrules` content
5. **Codebase index**: If indexed, the model uses semantic code search

### Tips for Better Suggestions

```
// BAD: Tab has no context about what you want
function process(data) {

// GOOD: Type signature gives Tab strong signal
function processPayment(
  amount: number,
  currency: 'USD' | 'EUR',
  paymentMethod: PaymentMethod
): Promise<PaymentResult> {
```

**Write descriptive function names and type signatures first.** Tab uses these as strong signals for generating the body.

### Using Comments as Prompts

```typescript
// Parse CSV file, skip header row, return array of objects with typed fields
function parseCSV(filepath: string): Promise<Record<string, string>[]> {
  // Tab will generate the full implementation based on the comment above
}
```

## Tab vs Other AI Features

| Feature | Trigger | Scope | Speed |
|---------|---------|-------|-------|
| **Tab** | Automatic while typing | Single completion | Instant (~100ms) |
| **Inline Edit (Cmd+K)** | Manual selection + prompt | Selected code block | ~2-5 seconds |
| **Chat (Cmd+L)** | Manual prompt | Conversational | ~3-10 seconds |
| **Composer (Cmd+I)** | Manual prompt | Multi-file | ~5-30 seconds |

Tab is the only feature that runs continuously as you type. It is optimized for speed over capability -- simple completions, not complex reasoning.

## Important Limitations

- **No custom models for Tab**: Even with BYOK (Bring Your Own Key), Tab always uses Cursor's proprietary model. Custom API keys apply to Chat and Composer only.
- **No reasoning**: Tab predicts the next tokens; it does not reason about correctness. Always review suggestions.
- **Context window**: Tab sees less context than Chat or Composer. For complex logic, use Cmd+K or Cmd+L instead.

## Conflict Resolution

If Tab conflicts with other extensions:

1. **Disable GitHub Copilot**: `Extensions` > search "Copilot" > Disable. Running both causes duplicate ghost text.
2. **Disable TabNine / Codeium**: Same issue -- only one inline completion provider should be active.
3. **VS Code IntelliSense**: Tab and IntelliSense coexist. IntelliSense handles imports/completions, Tab handles multi-line generation.

Remap if needed: `Cmd+K Cmd+S` > search `acceptCursorTabSuggestion` > assign new key.

## Measuring Tab Effectiveness

Tab gets better with usage. The model learns from:
- **Accepts** (Tab): Reinforces the pattern
- **Rejects** (Esc): Discourages similar suggestions
- **Partial accepts** (Cmd+→): Signals which parts were useful

After a few days on a project, Tab suggestions become noticeably more aligned with your coding style.

## Enterprise Considerations

- Tab suggestions are generated using Cursor's proprietary model -- not configurable via API keys
- Privacy Mode applies to Tab: with Privacy Mode on, code sent for Tab predictions has zero data retention
- Tab is included in all Cursor plans (Free tier has limited daily uses)
- No audit logging for individual Tab completions

## Resources

- [Cursor Tab Documentation](https://docs.cursor.com/tab/overview)
- [Keyboard Shortcuts](https://docs.cursor.com/kbd)
- [Privacy and Data Use](https://cursor.com/data-use)