Anthropic Native Configuration

Why Choose Anthropic Native Mode

OpenClaw supports two ways to call Claude models. If you need tool calling (tool_use) and other advanced features, Anthropic native mode (anthropic-messages) is strongly recommended:

Scenario	OpenAI Compatible Mode	Anthropic Native Mode
Basic Chat	✅ Works	✅ Works
Tool Calling (tool loop)	❌ May return 400	✅ Stable
Prompt Caching	❌ Not supported	✅ Supported
Multi-model Switching	✅ 400+ models	⚠️ Claude series only

With openai-completions, basic chat works fine, but multi-turn tool calling (tool_calls → tool_result → tool loop) may be rejected with a 400 error. Switching to anthropic-messages allows tool_use + tool_result format to work properly.

Recommended Configuration

Edit ~/.openclaw/openclaw.json and add the following provider configuration:

{
  "models": {
    "providers": {
      "apiyi": {
        "baseUrl": "https://api.apiyi.com",
        "apiKey": "sk-your-apiyi-key",
        "api": "anthropic-messages",
        "headers": {
          "anthropic-version": "2023-06-01",
          "anthropic-beta": ""
        },
        "models": [
          {
            "id": "claude-sonnet-4-6",
            "name": "Claude Sonnet 4",
            "reasoning": false,
            "contextWindow": 200000,
            "maxTokens": 16384
          },
          {
            "id": "claude-opus-4-6",
            "name": "Claude Opus 4",
            "reasoning": false,
            "contextWindow": 200000,
            "maxTokens": 16384
          }
        ]
      }
    }
  }
}

Critical Configuration Notes

The following three points must be set correctly, or you will encounter 400 errors:

baseUrl without /v1: Must be https://api.apiyi.com — adding /v1 would result in .../v1/v1/messages causing request failure
headers must include anthropic-version: Set to 2023-06-01
anthropic-beta set to empty string: Disables beta feature headers to avoid triggering unsupported features

About `reasoning: false`

Claude models on APIYI will return a 400 error if the request contains thinking-related fields (thinking / output_config).Setting "reasoning": false in the model entry prevents OpenClaw from sending thinking fields, avoiding this issue.

Model Allowlist Configuration

Add models to agents.defaults.models, otherwise OpenClaw may report the model as “unregistered” and silently fall back to another model:

{
  "agents": {
    "defaults": {
      "model": { "primary": "apiyi/claude-sonnet-4-6" },
      "models": {
        "apiyi/claude-sonnet-4-6": { "streaming": false },
        "apiyi/claude-opus-4-6": { "streaming": false }
      }
    }
  }
}

Comparison with OpenAI Compatible Mode

Feature	OpenAI Compatible Mode	Anthropic Native Mode
API Type	`openai-completions`	`anthropic-messages`
baseUrl	`https://api.apiyi.com/v1`	`https://api.apiyi.com`
Supported Models	All 400+ models	Claude series only
Tool Calling	Unstable (multi-turn may 400)	Stable
Prompt Caching	Not supported	Supported
Extended Context	Depends on model	Up to 200K tokens
Best For	Multi-model switching, basic chat	Deep Claude usage, Agent tool calling

Claude Model ID List

Model ID	Name	Description
`claude-sonnet-4-6`	Claude Sonnet 4	Balanced performance, recommended for daily use
`claude-opus-4-6`	Claude Opus 4	Strongest reasoning capability
`claude-haiku-4-5-20251001`	Claude Haiku 4.5	Fast response, cost-effective

Mixed Configuration (Recommended)

Configure both OpenAI compatible and Anthropic native providers, switching as needed:

{
  "agents": {
    "defaults": {
      "model": { "primary": "apiyi-claude/claude-sonnet-4-6" },
      "models": {
        "apiyi-claude/claude-sonnet-4-6": { "streaming": false },
        "apiyi-claude/claude-opus-4-6": { "streaming": false }
      }
    }
  },
  "models": {
    "providers": {
      "apiyi": {
        "baseUrl": "https://api.apiyi.com/v1",
        "apiKey": "sk-your-apiyi-key",
        "api": "openai-completions",
        "models": [
          { "id": "gpt-5.4", "name": "GPT-5.4" },
          { "id": "deepseek-v3.2", "name": "DeepSeek V3.2" }
        ]
      },
      "apiyi-claude": {
        "baseUrl": "https://api.apiyi.com",
        "apiKey": "sk-your-apiyi-key",
        "api": "anthropic-messages",
        "headers": {
          "anthropic-version": "2023-06-01",
          "anthropic-beta": ""
        },
        "models": [
          {
            "id": "claude-sonnet-4-6",
            "name": "Claude Sonnet 4",
            "reasoning": false,
            "contextWindow": 200000,
            "maxTokens": 16384
          },
          {
            "id": "claude-opus-4-6",
            "name": "Claude Opus 4",
            "reasoning": false,
            "contextWindow": 200000,
            "maxTokens": 16384
          }
        ]
      }
    }
  }
}

Use /model apiyi/gpt-5.4 or /model apiyi-claude/claude-sonnet-4-6 in chat to switch models.

Verify Configuration

After setup, verify that the configuration is working:

{/* Check model status */}
openclaw models status

{/* Send a test message and check the returned provider/model */}
openclaw agent --message "just reply pong" --json

In the returned JSON, check that meta.agentMeta.provider and meta.agentMeta.model match your configuration.

Troubleshooting

400 ValidationException: Operation not allowed

This is usually caused by thinking-related fields in the request. Ensure:

Model entries have "reasoning": false set
Headers include "anthropic-beta": "" correctly configured

Configuration changed but not taking effect

Existing chat sessions may have cached the old model configuration. Two solutions:Patch the session model:

openclaw gateway call sessions.patch \
  --params '{"key":"your-session-key","model":"apiyi-claude/claude-sonnet-4-6"}'

Or reset the session:

openclaw gateway call sessions.reset \
  --params '{"key":"your-session-key","reason":"reset"}'

Model silently falls back to another model

Check if the model has been added to the agents.defaults.models allowlist. Unregistered models will be automatically fallen back by OpenClaw.

baseUrl path duplication error

The Anthropic native mode baseUrl must not include /v1. Using https://api.apiyi.com/v1 will result in .../v1/v1/messages, causing a 404 error.

Overview

Conversational AI

Programming

Community Contributions

AI Agent

Engineering

Translation

Why Choose Anthropic Native Mode

Recommended Configuration

Critical Configuration Notes

About `reasoning: false`

Model Allowlist Configuration

Comparison with OpenAI Compatible Mode

Claude Model ID List

Mixed Configuration (Recommended)

Verify Configuration

Troubleshooting

​Why Choose Anthropic Native Mode

​Recommended Configuration

​Critical Configuration Notes

​About reasoning: false

​Model Allowlist Configuration

​Comparison with OpenAI Compatible Mode

​Claude Model ID List

​Mixed Configuration (Recommended)

​Verify Configuration

​Troubleshooting

Why Choose Anthropic Native Mode

Recommended Configuration

Critical Configuration Notes

About `reasoning: false`

Model Allowlist Configuration

Comparison with OpenAI Compatible Mode

Claude Model ID List

Mixed Configuration (Recommended)

Verify Configuration

Troubleshooting