### Answer Based on the available sources, I don't have specific documentation addressing the issue of an agent ignoring day-of-week restrictions in prompts. However, here are a few approaches that may help: 1. Filter Sunday slots at the n8n level Rather than relying on the LLM to respect "do not book on Sunday" instructions, ensure your n8n workflow excludes Sunday timeslots entirely from the

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before passing it to Retell. This removes the possibility of the agent selecting unavailable times. [(1) ]() 2. Use assertive transition conditions When using Conversation Flow, make transition conditions more assertive. For example, instead of general instructions, use explicit conditions like "only proceed when the selected time is NOT on a Sunday." 3. Add validation in your booking function Have your n8n booking endpoint validate the selected time and return an error if it falls on Sunday, prompting the agent to ask for a different time. The LLM may not reliably follow negative instructions ("do not book on Sunday") , so the most reliable approach is to never present Sunday as an option in the data you feed to the agent. Check out these potentially useful sources: - [I am not sure how to to link retell and my n8n booking process]() - [Part 1: Build Your First Retell Voice AI Agent That Sells Cars]() - [Personalization with Google Sheets]() Would you like me to provide a general answer on prompt engineering strategies for enforcing constraints?

​ To learn more, see the sources I considered: [[1] I am not sure how to to link retell and my n8n booking process](https://discord.com/channels/1186424376300679209/1413908347945615361) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.