URGENT: How to Set Up Claude Opus 4.6 on OpenClaw

Why “URGENT”

On February 5, 2026, Anthropic released Claude Opus 4.6. 1 million token context, 128K token output, enhanced planning and self-correction capabilities.

If you’re an OpenClaw user, you want to set this up right now. For a deeper look at how to leverage Opus 4.6’s tool-calling capabilities, see the Claude Agent SDK Tool Use Complete Guide.

This post gives you the shortest path to a working setup — copy, paste, and go.

Prerequisites

• OpenClaw installed (npm install -g openclaw@latest)
• Anthropic API key configured (claude setup-token)

If not, see the official docs. If you’re also using Claude Code, Claude Code Best Practices is worth reviewing for workflow setup.

Editing the Config File

Open ~/.openclaw/openclaw.json and add or modify these two sections.

1. models — Define Opus 4.6

"models": {
  "mode": "merge",
  "providers": {
    "anthropic": {
      "baseUrl": "https://api.anthropic.com",
      "api": "anthropic-messages",
      "models": [
        {
          "id": "claude-opus-4-6",
          "name": "Claude Opus 4.6",
          "reasoning": true,
          "input": ["text", "image"],
          "contextWindow": 1000000,
          "maxTokens": 128000
        }
      ]
    }
  }
}

Key points:

• mode: "merge" — adds to OpenClaw’s built-in model catalog (doesn’t replace it)
• reasoning: true — enables Opus 4.6 reasoning mode
• contextWindow: 1000000 — full 1M token context
• maxTokens: 128000 — 128K token long output

2. agents — Set the Default Model

"agents": {
  "defaults": {
    "model": {
      "primary": "anthropic/claude-opus-4-6",
      "fallbacks": [
        "anthropic/claude-opus-4-5"
      ]
    },
    "contextTokens": 1000000
  }
}

Key points:

• primary — uses Opus 4.6 as default for all sessions
• fallbacks — falls back to Opus 4.5 when Opus 4.6 is unavailable
• contextTokens: 1000000 — lets the agent use the full 1M context

Applying the Config

After saving, two steps are required.

Step 1: Restart the Gateway

openclaw gateway restart

This reloads the config file.

Step 2: Start a New Session

Existing sessions retain the old model config. Send this in chat:

/new

Or /reset. The new model won’t apply until you start a new session.

Verify the Setup

Check if the config is correct:

openclaw models status

If anthropic/claude-opus-4-6 shows as the primary model, you’re good.

You can also check from within chat:

/model status

Summary

1. Edit the models and agents sections in openclaw.json
2. Run openclaw gateway restart
3. Start a new session with /new
4. Verify with openclaw models status

That’s it. Welcome to the world of 1 million token context. To track usage and costs over time, Claude Code Usage Insights Analysis has the monitoring setup you need.

References

• OpenClaw Docs — Models
• OpenClaw Docs — Model Providers
• OpenClaw GitHub
• Anthropic — Claude Opus 4.6