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

# Anthropic

> Anthropic Claude LLM provider — Messages API with streaming, tool use, and prompt caching.

# Anthropic LLM

`AnthropicLLM` plugs Anthropic's Claude models into Patter's pipeline mode. It speaks the Messages API natively (streaming + `tool_use` blocks) and normalises every event into Patter's unified `{type: "text" | "tool_call" | "done"}` chunk protocol, so tools defined once run across every LLM provider.

Prompt caching is **enabled by default**. The system prompt and the last tool block are tagged with `cache_control: { type: "ephemeral" }`, which cuts time-to-first-token by \~100-400 ms and \~90% of input-token cost on every cached turn.

## Install

```bash theme={null}
pip install "getpatter[anthropic]"
```

```bash theme={null}
npm install getpatter
```

## Usage

<CodeGroup>
  ```python Python theme={null}
  # Namespaced import
  from getpatter.llm import anthropic

  llm = anthropic.LLM()                                       # reads ANTHROPIC_API_KEY
  llm = anthropic.LLM(api_key="sk-ant-...", model="claude-haiku-4-5-20251001")
  llm = anthropic.LLM(prompt_caching=False)                   # opt out of caching

  # Flat alias (equivalent)
  from getpatter import AnthropicLLM

  llm = AnthropicLLM()
  ```

  ```ts TypeScript theme={null}
  // Namespaced import
  import * as anthropic from "getpatter/llm/anthropic";

  const llm = new anthropic.LLM();                            // reads ANTHROPIC_API_KEY
  const llm = new anthropic.LLM({ apiKey: "sk-ant-...", model: "claude-haiku-4-5-20251001" });
  const llm = new anthropic.LLM({ promptCaching: false });    // opt out of caching

  // Flat alias (equivalent)
  import { AnthropicLLM } from "getpatter";

  const llm2 = new AnthropicLLM();
  ```
</CodeGroup>

<Note>
  The namespaced import (`from getpatter.llm import anthropic` / `import * as anthropic from "getpatter/llm/anthropic"`) auto-resolves the API key from `ANTHROPIC_API_KEY` and exposes a uniform `LLM` class — the same pattern Patter uses for STT and TTS namespaces.
</Note>

Plug it into an agent:

<CodeGroup>
  ```python Python theme={null}
  import asyncio
  from getpatter import Patter, Twilio, DeepgramSTT, AnthropicLLM, ElevenLabsTTS

  phone = Patter(carrier=Twilio(), phone_number="+15550001234")

  agent = phone.agent(
      stt=DeepgramSTT(),
      llm=AnthropicLLM(),                                     # ANTHROPIC_API_KEY from env
      tts=ElevenLabsTTS(voice_id="rachel"),
      system_prompt="You are a helpful assistant.",
      first_message="Hi, how can I help?",
  )

  asyncio.run(phone.serve(agent))
  ```

  ```ts TypeScript theme={null}
  import { Patter, Twilio, DeepgramSTT, AnthropicLLM, ElevenLabsTTS } from "getpatter";

  const phone = new Patter({ carrier: new Twilio(), phoneNumber: "+15550001234" });

  const agent = phone.agent({
    stt: new DeepgramSTT(),
    llm: new AnthropicLLM(),                                  // ANTHROPIC_API_KEY from env
    tts: new ElevenLabsTTS({ voiceId: "rachel" }),
    systemPrompt: "You are a helpful assistant.",
    firstMessage: "Hi, how can I help?",
  });

  await phone.serve(agent);
  ```
</CodeGroup>

## Supported models

Pricing in USD per 1M tokens. `cache_read` is billed at \~10% of full input; `cache_write` at \~125%. Versioned snapshots (e.g. `claude-haiku-4-5-20251001`) resolve against the base entry via longest-prefix match in [`pricing.py`](https://github.com/PatterAI/Patter/blob/main/libraries/python/getpatter/pricing.py).

| Model                        | Input   | Output  | Cache read | Cache write |
| ---------------------------- | ------- | ------- | ---------- | ----------- |
| `claude-opus-4-7`            | \$15.00 | \$75.00 | \$1.50     | \$18.75     |
| `claude-sonnet-4-6`          | \$3.00  | \$15.00 | \$0.30     | \$3.75      |
| `claude-haiku-4-5` (default) | \$1.00  | \$5.00  | \$0.10     | \$1.25      |

Aliases that route to the latest snapshot: `claude-haiku-4-5`, `claude-sonnet-4-6`, `claude-opus-4-7`, `claude-3-5-sonnet-latest`, `claude-3-5-haiku-latest`. Pinned snapshots include `claude-haiku-4-5-20251001`, `claude-3-5-sonnet-20241022`, `claude-3-5-haiku-20241022`.

## Environment variables

| Variable            | Required | Notes                                             |
| ------------------- | -------- | ------------------------------------------------- |
| `ANTHROPIC_API_KEY` | yes      | Auto-loaded when `api_key` / `apiKey` is omitted. |

## Options

| Option                             | Default                       | Notes                                                                                                                                                                                                                                                       |
| ---------------------------------- | ----------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `api_key` / `apiKey`               | `None`                        | Reads from `ANTHROPIC_API_KEY` when omitted.                                                                                                                                                                                                                |
| `model`                            | `"claude-haiku-4-5-20251001"` | Any Anthropic Claude model id or alias.                                                                                                                                                                                                                     |
| `max_tokens` / `maxTokens`         | `1024`                        | Required by the Messages API on every request.                                                                                                                                                                                                              |
| `temperature`                      | unset                         | Optional sampling temperature.                                                                                                                                                                                                                              |
| `base_url` / `baseUrl`             | unset                         | Override the Messages API endpoint (rarely needed).                                                                                                                                                                                                         |
| `prompt_caching` / `promptCaching` | `True`                        | Tags the system prompt and last tool block with `cache_control: ephemeral`. Disable when system prompt + tools are below Anthropic's minimum cacheable size (\~1024 tokens for Sonnet/Opus, \~2048 for Haiku) — caching has no effect below that threshold. |

## Prompt caching

For voice agents with long instruction-dense system prompts and large tool catalogs, prompt caching is the single biggest TTFT win Anthropic ships. Patter applies the recommended pattern automatically:

* The **system prompt** becomes a single `text` block tagged `cache_control: ephemeral`.
* The **last tool definition** is tagged `cache_control: ephemeral`, which caches the entire tool array (Anthropic caches everything up to and including a marked block).
* The `anthropic-beta: prompt-caching-2024-07-31` header is sent on every request for consistent behaviour across model snapshots.

The cache lives \~5 minutes — the first request writes it, subsequent requests within that window hit it for \~90% input-token savings on the cached portion.