Resolving "Reasoning is required" in OpenClaw v2026.3.28

What's Happening\n\nAfter upgrading to v2026.3.28, you are likely receiving the error message "Reasoning is required for this model endpoint. Use /think minimal (or any non-off level) and try again." This happens regardless of the model you select via OpenRouter. It is a configuration regression that forces agents to specify a thinking mode that previously had an implicit default.\n\n## The Fix\n\nYou can resolve this by updating your agent configuration in the web dashboard. Follow these steps:\n\n1. Open your OpenClaw dashboard.\n2. Navigate to Settings > AI & Agents > Agent.\n3. Find the Thinking Default option.\n4. Set it to minimal or any level other than "off".\n5. Save your changes and retry your request.\n\nThis change persists across your requests and stops the error from triggering.\n\n## Why This Occurs\n\nThe latest update introduced stricter requirements for model endpoint parameters. The system now mandates that an explicit thinking level is defined for the agent before it communicates with the provider. Since the upgrade did not migrate old "off" settings to a valid, explicitly defined state, the API validation fails immediately upon hitting the endpoint.\n\n## Prevention\n\nTo avoid this in the future, always verify your Agent settings immediately after a version upgrade. If you see breaking changes in the release notes regarding AI models, assume that your existing model chain configurations may require a manual "re-save" or update in the settings UI to populate new required parameters like the thinking level. If you continue to see this error after applying the fix, ensure your local npm global package is fully synchronized by running npm install -g openclaw@latest to ensure you aren't running a partial or corrupted install.

Last Updated: April 2026