> ## Documentation Index
> Fetch the complete documentation index at: https://agent-compass.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Anthropic Messages

> Connect AgentCompass to Anthropic Messages-compatible endpoints.

Use the `anthropic` protocol for Claude-style Anthropic Messages endpoints, commonly exposed at `/v1/messages`.

## Configure the Protocol

```bash theme={"system"}
export MODEL_NAME=""
export MODEL_BASE_URL="https://your-endpoint.example"
export MODEL_API_KEY="sk-ant-..."

agentcompass run <benchmark> <harness> "$MODEL_NAME" \
  --env <environment> \
  --model-base-url "$MODEL_BASE_URL" \
  --model-api-key "$MODEL_API_KEY" \
  --model-api-protocol anthropic \
  --model-params '{"max_tokens":4096,"temperature":0}'
```

The CLI protocol id is `anthropic`, while the documentation and user interface describe it as **Anthropic Messages**.

## Message Conversion

When a runtime component uses the shared Anthropic client, AgentCompass combines chat-style `system` messages into the Anthropic request's top-level `system` field and forwards the remaining messages to the Messages API.

Anthropic endpoints commonly require an explicit `max_tokens` value. Other request parameters are forwarded when supported by the endpoint and selected harness.

## Harness Compatibility

Protocol support is declared by each harness. For example, Claude Code uses Anthropic-compatible credentials, while many other harnesses are designed around OpenAI-compatible protocols. Always confirm compatibility on the selected [Harness](/en/user_guide/modules/harnesses/overview) page.

See [Model Configuration](/en/user_guide/modules/models/overview) for shared fields and [OpenAI Chat](/en/user_guide/modules/models/openai_chat) or [OpenAI Responses](/en/user_guide/modules/models/openai_responses) for the other built-in protocols.