How to create a Slack flow to connect user questions to Gemini for responses

Hi ​@renatomsantos, welcome to the Zapier Community 👋

Short answer: not exactly in the way you described, but you can get very close with a slightly different setup.

Right now, Zapier’s Slack integration can’t trigger on 1:1 direct messages (DMs).

However, you can build something similar using a dedicated Slack channel and the Google AI Studio (Gemini) app:

• Have users post their questions in a specific channel (for example, #ask-gemini).

• Use a Zap with:
  • Trigger: Slack – New Message Posted to Channel (watching that channel) or New Message Posted to Private Channel.
  • Action: Google AI Studio (Gemini) – Send Prompt or Conversation (where you put the same instructions/persona you used for your custom Gem into the “System instructions” field).
  • Action: Slack – Send Channel Message (or thread reply) to post Gemini’s answer back in Slack.
     

You can find all of our available Slack actions and triggers here.

One other important detail: Zapier can’t call a consumer “Gem” directly. Instead, you recreate that Gem’s behavior by copying its instructions into the Gemini action inside Zapier, so the API behaves like your specialist Gem.

Hope this helps 😄

Welcome to Zapier, this is a very common first-time question, so you’re on the right track.

The reason you’re stuck is because Gemini “Gems” aren’t selectable as a destination inside Zapier by default. Zapier can send prompts to Gemini, but it doesn’t automatically know which custom Gem to use unless you explicitly include that context in the prompt or call the correct Gemini endpoint.

To make this work, start your Zap with Slack using the “New Mention” or “New Message Posted to Channel” trigger and scope it to the specific DM or user. Make sure you’re capturing the message text and the user ID. Then add the Gemini action and use “Send Prompt” (or Webhooks by Zapier if you’re using the Gemini API directly). In the prompt field, clearly instruct Gemini to behave as your product-support Gem by pasting the same system instructions you used when creating the Gem, followed by the Slack question as the user message.

Once Gemini responds, add a Slack action using “Send Direct Message” or “Reply to Message” and map the Gemini response back to the original user or thread so it feels like a natural conversation.

If you want this to scale cleanly, the best approach is to store your Gem’s instructions in Storage by Zapier and inject them into every prompt, or use Webhooks by Zapier to call the Gemini API with a fixed system prompt so the behavior is always consistent.

Hello ​@renatomsantos 

Totally valid question and a very common first Zapier setup 

The main thing to know is that Zapier can’t directly point to an existing Gemini Gem. Zapier doesn’t “see” Gems as selectable objects. To get the same behavior, you recreate the Gem using your prompt.

A simple pattern that works well:

Slack trigger
Use New Message Posted or New Mention, scoped to DMs or messages to that specific user.

Filter by Zapier
Only continue when the message matches the user or DM you care about.

AI step
Use AI by Zapier or Webhooks by Zapier to send the message to Gemini. Paste the same system instructions you used when building the Gem so Gemini answers like that specialist.

Slack reply
Send the response back with Send Direct Message or Reply in Thread.

In short, think of a Gemini Gem as a saved prompt. In Zapier, that prompt just lives inside your AI step.

Dr. Tanvi Sachar
Monday Certified Partner, Tuesday Wizard