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

# Anthropic

> Use Claude models - Opus, Sonnet, and Haiku - via the Anthropic API. Best-in-class tool calling, coding, and reasoning.

Anthropic's Claude models are the default recommended provider in profClaw. They offer native tool calling, vision support, and large context windows up to 1M tokens.

## Supported Models

| Model             | ID                           | Context | Max Output | Tools | Vision | Input \$/1M | Output \$/1M |
| ----------------- | ---------------------------- | ------- | ---------- | ----- | ------ | ----------- | ------------ |
| Claude Opus 4.6   | `claude-opus-4-6`            | 1M      | 128K       | Yes   | Yes    | \$5.00      | \$25.00      |
| Claude Sonnet 4.5 | `claude-sonnet-4-5-20250929` | 200K    | 16K        | Yes   | Yes    | \$3.00      | \$15.00      |
| Claude Haiku 4.5  | `claude-haiku-4-5-20251001`  | 200K    | 8K         | Yes   | Yes    | \$0.25      | \$1.25       |

## Setup

<Steps>
  <Step title="Get an API key">
    Sign up at [console.anthropic.com](https://console.anthropic.com) and create an API key.
  </Step>

  <Step title="Set the environment variable">
    ```bash theme={null}
    export ANTHROPIC_API_KEY=sk-ant-api03-...
    ```

    Or add it to your `.env` file.
  </Step>

  <Step title="Verify configuration">
    ```bash theme={null}
    profclaw doctor --provider anthropic
    ```
  </Step>
</Steps>

## Environment Variables

<ParamField path="ANTHROPIC_API_KEY" type="string" required>
  Your Anthropic API key. Format: `sk-ant-api03-...`
</ParamField>

<ParamField path="ANTHROPIC_BASE_URL" type="string">
  Override the API base URL. Useful for proxies or custom endpoints. Defaults to `https://api.anthropic.com`.
</ParamField>

## Configuration Example

<Tabs>
  <Tab title=".env">
    ```bash theme={null}
    ANTHROPIC_API_KEY=sk-ant-api03-...
    ```
  </Tab>

  <Tab title="settings.yml">
    ```yaml theme={null}
    providers:
      default: anthropic
      anthropic:
        api_key: "${ANTHROPIC_API_KEY}"
        # Optional: custom endpoint
        # base_url: "https://your-proxy.example.com"
    ```
  </Tab>

  <Tab title="CLI">
    ```bash theme={null}
    profclaw config provider add anthropic --key sk-ant-api03-...
    profclaw config provider set-default anthropic
    ```
  </Tab>
</Tabs>

## Model Aliases

| Alias    | Model                      |
| -------- | -------------------------- |
| `opus`   | claude-opus-4-6            |
| `sonnet` | claude-sonnet-4-5-20250929 |
| `haiku`  | claude-haiku-4-5-20251001  |

## Usage Examples

<CodeGroup>
  ```bash CLI theme={null}
  # Use default model (auto-selected)
  profclaw chat "Explain async/await in JavaScript"

  # Use a specific alias
  profclaw chat --model opus "Review this architecture"

  # Use full model ID
  profclaw chat --model claude-haiku-4-5-20251001 "Quick question"
  ```

  ```typescript SDK theme={null}
  import { chat } from 'profclaw';

  const response = await chat("Write a test for this function", {
    model: "opus",
    systemPrompt: "You are a senior TypeScript engineer.",
    temperature: 0.3,
  });
  ```

  ```bash Agent theme={null}
  profclaw agent run --model sonnet --task "Review PR #42 in profclaw/profclaw"
  ```
</CodeGroup>

## Notes

* Anthropic is the top-priority provider in profClaw's auto-selection order.
* All Claude models support native function calling - tools work reliably without fallback prompting.
* Opus has a 1M token context window, suitable for large codebases.
* Claude Haiku 4.5 is the recommended model for high-throughput, cost-sensitive workloads.

## Related

* [AI Providers Overview](/ai-providers/overview) - Compare all 37 supported providers
* [OpenAI](/ai-providers/openai) - GPT-4o and o-series reasoning models
* [profclaw provider](/cli/provider) - Add and test providers from the CLI
* [profclaw models](/cli/models) - List and manage model aliases