# Quickstart

### 1. Install C0

Open the Extensions view (`Cmd+Shift+X` on Mac, `Ctrl+Shift+X` on Windows/Linux) and search for   **C0**.

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### 2. Sign in

On first launch, C0 will prompt you to sign in. Click **Sign in with C0** and complete authentication in your browser. Once signed in, you'll be returned to your IDE automatically.

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### 3. Open a project and let C0 index it

Open any project folder in your IDE. C0 will detect it and begin indexing your codebase automatically.

You'll see a status indicator in the C0 panel:

* **Indexing:** C0 is reading your files and building its knowledge base
* **Ready:** indexing is complete; C0 now understands your codebase

For small projects, indexing takes under a minute. For larger codebases, it may take a few minutes on the first run. After that, C0 only re-indexes files that have changed, so subsequent updates are nearly instant.

> **Note:** You can start using C0 before indexing finishes. Results will improve as indexing progresses.

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### 4. Try your first workflow

Once indexing completes, try one of these to see C0 in action:

**Ask a question about your code:**

Open the C0 chat panel and type:

```
@<Select your Knowledgebase> How does authentication work in this project?
```

C0 will read the relevant files, trace the flow, and give you a clear explanation grounded in your actual codebase not a generic answer.

**Debug an error:**

Switch to **Debug mode** in the C0 panel, paste an error message or stack trace, and hit enter:

```
TypeError: Cannot read properties of undefined (reading 'userId')
  at AuthMiddleware.verify (src/middleware/auth.js:34)
```

C0 will locate the source of the problem, explain why it's happening, and offer a fix.

**Generate tests for a file:**

Switch to **Generate tests** mode, select a file or function, and run it. C0 will produce a full test suite matched to your project's existing test framework and conventions.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.codemate.ai/c0/quickstart.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.