> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cubic.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Developer quickstart

> Get hands-on with cubic AI code review in minutes.

This guide walks you through setting up and using cubic's AI code reviewer for the first time. By the end, you'll know how to install the app, trigger reviews, interact with AI comments, and set up custom agents.

## 1. Install the cubic GitHub App

<Steps>
  <Step title="Sign up">
    Go to [cubic.dev/sign-up](https://cubic.dev/sign-up) and sign in with your GitHub account.
  </Step>

  <Step title="Authorize GitHub and start your free trial">
    Authorize cubic to access the repositories you want to review. You'll get 7 days free, no credit card required.
  </Step>
</Steps>

## Share with your team

Copy and paste this message into Slack after you install cubic:

```text theme={null}
Heads up: we've enabled cubic (https://cubic.dev) on our repositories — the [top-ranked AI code reviewer](https://codereview.withmartian.com/?mode=offline) on independent benchmarks.

What this means day to day:

- New PRs get an automatic AI review on GitHub. Expect inline comments when it spots something worth a look.
- Reply to its comments like you would to a teammate — including when something isn't useful. Replies tune it for our codebase over time.
- Run reviews locally before you push with the CLI — https://docs.cubic.dev/ide/cli-review
- Tag @cubic-dev-ai in a PR comment to re-run a review, ask for clarification, or request a fix.

More info: https://docs.cubic.dev/ai-review/quickstart
```

## 2. Trigger your first review

To get your first AI review, you have two options:

**Option 1: Open a new pull request**

cubic automatically reviews new pull requests within a few minutes.

```bash theme={null}
git checkout -b feature/my-feature
# Make some changes
git add .
git commit -m "Add new feature"
git push origin feature/my-feature
```

Open the PR on GitHub, and cubic will automatically start the review.

**Option 2: Tag cubic in an existing PR**

For existing pull requests, add a comment tagging `@cubic-dev-ai` to trigger a review. cubic will start within a few minutes.

**What you'll see:**

* A comment from `@cubic-dev-ai` with the PR summary
* Inline comments on specific code changes pointing out bugs and improvements
* Actionable suggestions with explanations

## 3. Interact with cubic

You can reply to cubic, provide feedback, and request changes.

<Steps>
  <Step title="Ask follow-up questions">
    Reply to any AI comment to ask for clarification:

    ```
    @cubic-dev-ai Can you explain why this is a concern?
    ```

    The AI will respond with more context.
  </Step>

  <Step title="Provide feedback">
    Help cubic learn by reacting to comments:

    * **Thumbs up** if the suggestion is helpful
    * **Thumbs down** if it's not relevant

    cubic remembers your feedback and improves over time.
  </Step>

  <Step title="Request fixes">
    Ask cubic to generate a fix:

    ```
    @cubic-dev-ai Can you fix this?
    ```

    If [background agents](/ai-review/key-features#background-agents) are enabled, cubic can automatically apply the fix.
  </Step>
</Steps>

<Tip>
  You can also ask cubic to explain code directly in PR comments, for example
  `@cubic-dev-ai explain this function`.
</Tip>

## 4. Use cubic in your editor

Once the GitHub review flow is working, add cubic to your coding agent so you can fix PR issues without leaving the editor and optionally add local reviews later.

* Use [Connect cubic to your IDE](/ide/agent-setup) to install cubic in Cursor, Claude Code, VS Code, Codex, Gemini CLI, or another coding tool.
* Use [Local CLI review](/ide/cli-review) if you want the advanced local-review loop in the terminal.
* Use [What to ask your agent](/ide/skills) for the best prompts and slash commands.

## 5. Set up your first custom agent

Custom agents are review rules that enforce team-specific standards. Let's create a simple one.

<Steps>
  <Step title="Navigate to custom agents">
    1. Go to [cubic.dev/dashboard](https://cubic.dev/dashboard)
    2. Select your repository
    3. Click **Custom Agents** in the sidebar
  </Step>

  <Step title="Create a rule">
    Click **New Rule** and define it using natural language:

    **Example rule:**

    ```
    All API endpoints must include error handling with try-catch blocks
    ```

    You can also use code patterns:

    ```regex theme={null}
    Avoid using `any` type in TypeScript function parameters
    ```
  </Step>

  <Step title="Test the rule">
    Open a new PR that violates the rule. cubic will flag it:

    ```typescript theme={null}
    // This will trigger the rule
    function apiCall(data: any) {
      return fetch('/api', { body: data })
    }
    ```

    cubic will comment: "This function parameter uses `any` type, which violates the custom agent."
  </Step>
</Steps>

<Note>For more advanced rule configurations, see [Custom review rules](/ai-review/custom-agents).</Note>

## 6. Use background agents

Background agents automatically fix issues without manual intervention.

<Steps>
  <Step title="Enable background agents">
    In your repository settings on [cubic.dev](https://cubic.dev), enable **Background Agents**.
  </Step>

  <Step title="Trigger a fix">
    When cubic identifies an issue, you can request a fix by clicking the **Fix with cubic** button in the GitHub comment, or by tagging cubic:

    ```
    @cubic Please fix this
    ```

    Use any supported cubic tag in the current comment when you want cubic to edit code:

    * `@cubic Please fix this`
    * `@cubic-dev-ai Please fix this`
    * `@cubic open a fix PR`

    <Note>
      Replying inside an existing cubic thread without a fresh cubic tag is treated as discussion,
      not permission to push changes.
    </Note>

    By default, cubic pushes commits to your PR branch. If you want a separate PR instead, include
    "open a fix PR."

    cubic will:

    1. Generate the fix
    2. Push commits to your PR branch by default, or open a fix PR when requested
    3. Update the comment with the result

    <video src="https://mintcdn.com/cubic-2/xfSZ1OCpUQhXsXtm/changelog/images/fix-progress.mp4?fit=max&auto=format&n=xfSZ1OCpUQhXsXtm&q=85&s=f095dd041a58ea4288e63a1e885a011b" autoPlay loop muted playsInline className="border border-zinc-800 rounded-lg" data-path="changelog/images/fix-progress.mp4" />
  </Step>

  <Step title="Review the fix">
    Check the new commit to verify the changes. You can always:

    * Request modifications
    * Revert the commit if needed
    * Provide feedback for future fixes
  </Step>
</Steps>

## 7. Explore PR summaries

cubic automatically generates PR descriptions based on your code changes.

When you create a PR, cubic will:

1. Analyze the diff
2. Generate a summary including:
   * What changed
   * Why it changed
   * Potential impacts
3. Post it as the first comment

You can also request a summary update:

```
@cubic-dev-ai update the PR summary
```

## What's next?

Now that you've experienced the basics, explore more features:

* [**Connect cubic to your IDE**](/ide/agent-setup): Install cubic in Cursor, Claude Code, VS Code, Codex, Gemini CLI, or another coding tool
* [**Local CLI review**](/ide/cli-review): Add the advanced local-review loop before you push
* [**What to ask your agent**](/ide/skills): Learn the best prompts and slash commands
* [**Key features**](/ai-review/key-features): Deep dive into all AI review capabilities
* [**Custom review rules**](/ai-review/custom-agents): Advanced rule configurations and patterns
* [**Memory and learning**](/ai-review/memory-and-learning): How cubic adapts to your codebase
* [**Interactive comments**](/ai-review/interactive-comments): Full list of AI commands and interactions
* [**Settings**](/ai-review/ai-review-settings): Configure review behavior and preferences

<Tip>
  Have questions? Check out the [FAQ section](/ai-review/introduction#frequently-asked-questions) or
  [contact support](/account/support).
</Tip>