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

# Claude Code

> Claude Code client integration guide: one-stop access to Claude / Kimi / GPT via GravitexAI

## 1. Overview

**Claude Code** is Anthropic's official terminal AI coding client. Through **GravitexAI** (Anthropic-compatible API) you get:

<CardGroup cols={2}>
  <Card title="Multi-vendor access" icon="plug">
    Use the full Claude family, Kimi K2, GPT and more behind one endpoint
  </Card>

  <Card title="Dual-thread model" icon="microchip">
    Heavy tasks on the main thread, lightweight ones on the haiku thread
  </Card>

  <Card title="No subscription" icon="wallet">
    Pay per token — no Claude Pro required
  </Card>

  <Card title="Stable globally" icon="globe">
    Distributed nodes with automatic failover
  </Card>
</CardGroup>

## 2. Install Node.js (skip if installed)

Make sure Node.js is **≥ 18.0**.

<Tabs>
  <Tab title="Windows">
    Download: [https://nodejs.org/dist/v22.18.0/node-v22.18.0-x64.msi](https://nodejs.org/dist/v22.18.0/node-v22.18.0-x64.msi)
  </Tab>

  <Tab title="macOS">
    ```bash theme={null}
    sudo xcode-select --install
    /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
    brew install node
    node --version
    ```
  </Tab>

  <Tab title="Ubuntu / Debian">
    ```bash theme={null}
    curl -fsSL https://deb.nodesource.com/setup_lts.x | sudo bash -
    sudo apt-get install -y nodejs
    node --version
    ```
  </Tab>
</Tabs>

### Uninstall other proxy clients (optional)

If you previously installed another forked `@anthropic-ai/claude-code`, clean it up first:

```bash theme={null}
# Check installation locations
npm ls @anthropic-ai/claude-code
npm ls -g @anthropic-ai/claude-code

# Uninstall
npm uninstall @anthropic-ai/claude-code
npm uninstall -g @anthropic-ai/claude-code
```

## 3. Install Claude Code

<Steps>
  <Step title="Global install">
    ```bash theme={null}
    npm install -g @anthropic-ai/claude-code
    ```
  </Step>

  <Step title="Verify install">
    ```bash theme={null}
    claude --version
    ```
  </Step>
</Steps>

## 4. Get your GravitexAI key

<Steps>
  <Step title="Sign in">
    Go to the [GravitexAI console](https://maas.gravitex.ai).
  </Step>

  <Step title="Create a key">
    Open [API Keys](https://maas.gravitex.ai/#/keys) → create a new token.
  </Step>

  <Step title="Note the info">
    ```
    base_url = "https://api.gravitex.ai"
    api_key  = "sk-zbTYx*******************************fceTvn5"
    ```

    <Warning>
      Claude Code's `ANTHROPIC_BASE_URL` does **not** need a `/v1` suffix — use `https://api.gravitex.ai` directly.
    </Warning>
  </Step>
</Steps>

## 5. Configure Environment Variables

### 5.1 Basic example (single model)

<Tabs>
  <Tab title="Mac / Linux">
    ```bash theme={null}
    export ANTHROPIC_BASE_URL="https://api.gravitex.ai"
    export ANTHROPIC_AUTH_TOKEN="sk-zbTYx*******************************fceTvn5"
    export ANTHROPIC_MODEL="kimi-k2-250905"
    cd your-project-folder
    claude
    ```
  </Tab>

  <Tab title="Windows CMD">
    ```cmd theme={null}
    set ANTHROPIC_BASE_URL=https://api.gravitex.ai
    set ANTHROPIC_AUTH_TOKEN=sk-zbTYx*******************************fceTvn5
    set ANTHROPIC_MODEL=kimi-k2-250905
    cd your-project-folder
    claude
    ```
  </Tab>

  <Tab title="Windows PowerShell">
    ```powershell theme={null}
    $env:ANTHROPIC_BASE_URL="https://api.gravitex.ai"
    $env:ANTHROPIC_AUTH_TOKEN="sk-zbTYx*******************************fceTvn5"
    $env:ANTHROPIC_MODEL="kimi-k2-250905"
    cd your-project-folder
    claude
    ```
  </Tab>
</Tabs>

### 5.2 Dual-thread architecture

By default Claude Code uses a **dual-thread** model architecture that saves cost:

| Thread    | Env var                         | Purpose                                                   |
| --------- | ------------------------------- | --------------------------------------------------------- |
| **Main**  | `ANTHROPIC_MODEL`               | Primary codegen, conversation, complex tasks              |
| **Haiku** | `ANTHROPIC_DEFAULT_HAIKU_MODEL` | File watching, linter checks, completion, background jobs |

<Tip>
  **Typical pairing**: main thread on `claude-opus-4-7` or `claude-sonnet-4-6` for heavy lifting, haiku thread on `claude-haiku-4-5-20251001` for background work — high quality at much lower token cost.
</Tip>

### 5.3 Recommended config (dual model)

<Tabs>
  <Tab title="Mac / Linux">
    ```bash theme={null}
    export ANTHROPIC_BASE_URL="https://api.gravitex.ai"
    export ANTHROPIC_AUTH_TOKEN="sk-zbTYx*******************************fceTvn5"
    export ANTHROPIC_MODEL="claude-sonnet-4-6"
    export ANTHROPIC_DEFAULT_HAIKU_MODEL="claude-haiku-4-5-20251001"
    cd your-project-folder
    claude
    ```
  </Tab>

  <Tab title="Windows CMD">
    ```cmd theme={null}
    set ANTHROPIC_BASE_URL=https://api.gravitex.ai
    set ANTHROPIC_AUTH_TOKEN=sk-zbTYx*******************************fceTvn5
    set ANTHROPIC_MODEL=claude-sonnet-4-6
    set ANTHROPIC_DEFAULT_HAIKU_MODEL=claude-haiku-4-5-20251001
    cd your-project-folder
    claude
    ```
  </Tab>

  <Tab title="Windows PowerShell">
    ```powershell theme={null}
    $env:ANTHROPIC_BASE_URL="https://api.gravitex.ai"
    $env:ANTHROPIC_AUTH_TOKEN="sk-zbTYx*******************************fceTvn5"
    $env:ANTHROPIC_MODEL="claude-sonnet-4-6"
    $env:ANTHROPIC_DEFAULT_HAIKU_MODEL="claude-haiku-4-5-20251001"
    cd your-project-folder
    claude
    ```
  </Tab>
</Tabs>

### 5.4 Single model (optional)

If you only want one model, there are two options:

**Option A — set both env vars to the same model**

```bash theme={null}
export ANTHROPIC_BASE_URL="https://api.gravitex.ai"
export ANTHROPIC_AUTH_TOKEN="sk-zbTYx*******************************fceTvn5"
export ANTHROPIC_MODEL="kimi-k2-250905"
export ANTHROPIC_DEFAULT_HAIKU_MODEL="kimi-k2-250905"
cd your-project-folder
claude
```

**Option B — switch in-session**

Keep the dual-model config, start Claude Code, then in the interactive UI:

```
/model haiku
```

The main thread switches to the model from `ANTHROPIC_DEFAULT_HAIKU_MODEL`.

## 6. Recommended Combinations (via GravitexAI)

| Scenario                    | Main (`ANTHROPIC_MODEL`)            | Haiku (`ANTHROPIC_DEFAULT_HAIKU_MODEL`) |
| --------------------------- | ----------------------------------- | --------------------------------------- |
| **Production** (top)        | `claude-opus-4-7`                   | `claude-haiku-4-5-20251001`             |
| **Daily dev** (recommended) | `claude-sonnet-4-6`                 | `claude-haiku-4-5-20251001`             |
| **Cost-optimized**          | `kimi-k2-250905`                    | `claude-haiku-4-5-20251001`             |
| **Long context**            | `claude-sonnet-4-5-20250929` (200K) | `claude-haiku-4-5-20251001`             |
| **Quick smoke-test**        | `claude-haiku-4-5-20251001`         | `claude-haiku-4-5-20251001`             |

See full IDs in the [GravitexAI model catalog](https://maas.gravitex.ai/#/models).

## 7. FAQ

<AccordionGroup>
  <Accordion title="401 / invalid API key">
    1. Check `ANTHROPIC_AUTH_TOKEN` for stray whitespace or newlines.
    2. Confirm the key is active in the [GravitexAI console](https://maas.gravitex.ai/#/keys).
    3. Ensure your balance is positive.
  </Accordion>

  <Accordion title="404 / wrong endpoint">
    For Claude Code, **do not** append `/v1` to `ANTHROPIC_BASE_URL`. Use `https://api.gravitex.ai` (Anthropic protocol differs from OpenAI).
  </Accordion>

  <Accordion title="How to switch models inside Claude Code?">
    In the interactive UI:

    ```
    /model              # show current model
    /model haiku        # switch to ANTHROPIC_DEFAULT_HAIKU_MODEL
    /model sonnet       # alias supported in some versions
    ```

    Or exit, change env vars, and re-launch.
  </Accordion>

  <Accordion title="`model not found` error">
    Use the **full ID** from the [GravitexAI model list](https://maas.gravitex.ai/#/models), e.g.:

    * ✅ `claude-sonnet-4-5-20250929`
    * ❌ `claude-sonnet-4-5`

    The version suffix is required.
  </Accordion>

  <Accordion title="How to reduce token cost?">
    1. Prefer the **dual-model** setup with Haiku as the background thread.
    2. Use `--max-turns` and similar flags to cap conversation length.
    3. Maintain project memory under `.claude/` to avoid repeating context.
    4. Use `/clear` to drop stale context.
  </Accordion>

  <Accordion title="Team-wide config?">
    Put env vars into a project `.env`, your shell profile, or `direnv`. Each engineer only swaps in their own `ANTHROPIC_AUTH_TOKEN`.
  </Accordion>
</AccordionGroup>

## 8. References

* Claude Code official docs: [https://docs.anthropic.com/en/docs/claude-code](https://docs.anthropic.com/en/docs/claude-code)
* GravitexAI console: [https://maas.gravitex.ai](https://maas.gravitex.ai)
* Model catalog: [https://maas.gravitex.ai/#/models](https://maas.gravitex.ai/#/models)
* API keys: [https://maas.gravitex.ai/#/keys](https://maas.gravitex.ai/#/keys)