Skip to main content

Get Support
Have a question? Let's get you an answer!

How Do I...? Troubleshooting Code & Webhooks Developer Zone

Other Help Resources
Wait, there's more! Check out these Community sourced spaces for additional resources.

Zapier Help Center Hire an Expert

Learning Resources
All of our best learning resources can be found here.

Featured Articles Show & Tell Zapier's products AI Hub Zapier Tools Hub

Share your knowledge
Give back to the Community by sharing your automation wins and helping to answer questions.

Share your success See unanswered questions User Groups

Other Learning Resources
Some of our favorite additional ways to upskill your Zapier knowledge.

Zapier Learn Zapier Blog Zapier Webinars

Product Updates
Check out what is new and upcoming with Zapier with our regular product updates.

Product Updates

Early Access Program
Want to join Early Access? Learn more here.

Question

AI Agent fails to update ClickUp custom field without specific value

  • November 27, 2025
  • 5 replies
  • 30 views
R

Hi there,

I am setting up an AI agent to perform actions with a ClickUp task. I’m able to get the ClickUp task and read custom fields. However, if I ask it to update a custom field with a value, such as simply “Hello”, it errors with message Error during execution: Value is not a valid string

Here are the resolved fields (with IDs redacted). All are correct.

Task Id
...
location
[{"list_id":"...","team_id":"...","space_id":"...","folder_id":"..."}]
change value
[{"cf__...":"Helloooooo"}]
Custom field id

Short Blurb (Auto-Generated) (...)

 

However, in the configuration, if I set a specific value for “Value”, then it’ll actually set my custom field to that value. But it runs into the error if I instruct it to set it to the same string in my prompt.

Very confused what’s happening here but I wonder if “change value” is supposed to just be a string and not an array. However, even with creative prompting, I can’t get the AI Agent to output just a string for “change value” in resolved fields.

Any help/guidance will be much appreciated!

 

5 replies

Sparsh from Automation Jinn
Forum|alt.badge.img+6

Hey ​@ramona,

Please post screenshots of how your Zapier agent is configured for us to have more context. You have to give your agent access to Update Custom Value action rather than a generic Update task action for updating custom fields. Hope it helps!

https://zapier.com/partnerdirectory/automation-jinn | Zapier Silver Solution Partner| Automationjinn.com
R
  • ramona
  • Author
  • New
  • November 27, 2025

HI ​@Sparsh from Automation Jinn, yes my agent has access to Update Custom Field Value with preselected fields. “Post a Task Comment” works which has the same settings. I also tested the “Update Custom Field Value” with the custom field IDs preselected in the configuration as well.

I’ve basically pared down my instructions to the below:

Note that Step 1 works but Step 2 hangs as mentioned in my original post.

Sparsh from Automation Jinn
Forum|alt.badge.img+6

Hey ​@ramona,

I think you should reference the tool in instructions to follow. Specifically Update Custom Field Value. You can use / to add tools or knowledge sources. Hope it helps!

https://zapier.com/partnerdirectory/automation-jinn | Zapier Silver Solution Partner| Automationjinn.com
R
  • ramona
  • Author
  • New
  • November 28, 2025

Hi ​@sp123, thank you for your suggestion. I was hopeful that would fix it, but it did not unfortunately.

I updated my prompt to reference the tool as suggested:

But I got the same error (Error during execution: Value is not a valid string) and response as before. I even updated the tool to specify the custom fields, but same error is occurring.

Sparsh from Automation Jinn
Forum|alt.badge.img+6

Hey ​@ramona,

Can you just put Helloooooo with no quotes around it and see if it fixes your issue. If it doesn’t work then I think your agent may be sending an object instead of a string. You can also try refining the prompt if it helps.

A workaround can be using Zap with agents for a more deterministic workflow. You can make a Zap that will call the agent and then you can update the custom value through a Zap action. 

Hope it helps!

PS: If you need more active help, I’m happy to connect through my Zapier Solution Partner page if you’d like to reach out here- https://zapier.com/partnerdirectory/automation-jinn

https://zapier.com/partnerdirectory/automation-jinn | Zapier Silver Solution Partner| Automationjinn.com
Terms & ConditionsAccessibility statement