Need help creating a Zap that draft Gmail replies to customer emails

Hy ​@EmilK 

Try following this official guide from Zapier:

https://zapier.com/blog/use-openai-gpt-3-to-write-emails/

Or use this ready-made Zap template:

https://zapier.com/apps/gmail/integrations/gmail/1156755/create-email-copy-with-openai-from-new-gmail-emails-and-save-as-drafts-in-gmail

Both walk you through setting up a Zap that:

• Triggers on new Gmail emails

• Uses ChatGPT (OpenAI) instead of "AI by Zapier"

• Creates a draft reply in Gmail

The key fix: replace "Analyze & Return Data" with OpenAI's "Write an Email" action. Set temperature to 0.1 and format to plain text. This eliminates the incorrect answers, ignored instructions, and markdown formatting you're seeing.

Hope this helps you get it sorted!

If you're still running into issues, drop a screenshot of the error and a quick description of what your Zap is doing, happy to take a look!

And if you'd rather just get it sorted quickly, I offer a free 20-min Zapier troubleshooting call. Book it under Resources on my Zapier Directory profile: https://zapier.com/partnerdirectory/automatemybiz

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Hi ​@EmilK 

Help links for using AI by Zapier in Zap: https://zapier.com/apps/ai/integrations#help

If you need more help, post screenshots showing how your Zap steps are outlined and configured.

​@Fahad S thank you for your reply.

Official guide from Zapier

I had a look and it seems this only uses Body Plain as input for writing the reply. There is no alternative to use other data/knowledge sources? This will never work for customer support purposes I’m afraid.

Ready made zap template

This forgoes  your recommendation to use “Write email” instead of “Analyze & return data”.

What are my options if I want smarter replies using data/knowledge other than the new email?

Hy ​@EmilK 

From Zapier’s documentation: https://help.zapier.com/hc/en-us/articles/8496342944013-Use-AI-by-Zapier-to-analyze-and-return-data

• It’s built around input fields + output fields, where

  “Output fields help structure the result”

• It does not learn from previous runs (no memory)

  “AI by Zapier does not learn from previous actions… knowledge is reset”

• It relies on only the context you provide via inputs or knowledge sources

Why your replies are inconsistent

Zapier explains this here: https://zapier.com/blog/ai-hallucinations/

AI can confidently generate incorrect answers if the required information isn’t clearly provided.
So if your prompt or knowledge is incomplete → it will guess.

How to fix your Zap

1. Add knowledge properly

• Upload your .txt files as Knowledge Sources

• Then explicitly instruct:

  “Use only the provided knowledge sources. Do not use outside information.”

2. Use a structured prompt like:

You are a customer support agent.

Customer email:
{{Body}}

Instructions:
- Answer only using provided knowledge sources
- If the answer is not explicitly found, say: "I'll check this and get back to you"
- Be concise and professional
- Return plain text only (no markdown)

Return JSON:
{
"subject": "...",
"reply": "..."
}

3. Map correctly in Gmail

• Use Create Draft Reply
• Map:

  • reply → Body

  • Thread ID → from trigger

Hope this helps you get it sorted! And let me know how it goes — happy to dig deeper if needed!