Sharepoint List - Muti Select Category Field

(2) Share

Report

Posted on by WM-02031008-0

Hi All,

I am creating an agent to help me manage a sharepoint list (risk register).

I am using the Sharepoint 'create item' and 'update item' tools in CoPilot Studio. I am running into issues with 1 specific column in my list: a multi select Choice column. I am getting HTTP error with code 400 or HTTP error with code 502.

I believe the issue is the way AI is sending the information for this column creation / update:

{
  "Category": [
    "Project",
    "Technical"
  ]
}

I think it should be something like:

{"Category": [
  { "Value": "Project" }
]
}

I have tried:

Explicitly telling the agent in the instructions about the above format
Looked into the Inputs on the tool:
- Site Address - Custom Value - my sharepoint site
- List Name - Custom Value - my sharepoint list
- ID - Dynamically fill with AI
- (Item) - this field doesn't show unless the ID is set to a custom value

Any help or hints would be greatly appreciated!

Categories:

General topics

I have the same question (0)

All responses (3)

Answers (1)

Sort by

Suggested answer

Haque 3,653 on at

Like
a
(1)

Report
Copy link

Link copied!
Hi @WM-02031008-0,

Apparently, a single choice column expects a string (e.g., "Lower") and a multi-choice column expects an array of objects, each with a value property. Hence, if we send just a string or a flat array of strings, SharePoint rejects it.

So SharePoint wants this:

{ "Category": [ { "Value": "Project" }, { "Value": "Technical" } ] }

But we are sendint this:

{ "Category": [ "Project", "Technical" ] }

Let's follow these steps to have a fix:

1. Collect selected values from your Copilot agent or input - if you have a multi‑select combo box, it returns an array of strings

2. Transform into the required object array using a Select action:

Input: ["Financial","Operational"] (just for example)

Mapping:

{ "Value": item() }

[ { "Value": "Project" }, { "Value": "Technical" } ]

3. Pass that array into the SharePoint Create item or Update item action for the multi‑select Choice column.

I am sure some clues I tried to give. If these clues help to resolve the issue brought you by here, please don't forget to check the box Does this answer your question? At the same time, I am pretty sure you have liked the response!

Was this reply helpful? Yes No
Suggested answer

Valantis 6,735 on at

Like
a
(1)

Report
Copy link

Link copied!
Hi @WM-02031008-0,

Here’s a possible fix to the Risk Register updates failing on the multi‑select Category field:

In the SharePoint Create item/Update item action, set Category to Enter custom value and pass an array of strings, e.g. ["Project","Technical"]. If using an expression: createArray('Project','Technical'). Do not send objects like [{"Value":"Project"}] — SharePoint rejects that format.

If you prefer REST via “Send an HTTP request to SharePoint”, use MERGE and the results wrapper:
Body:
{
"__metadata": { "type": "SP.Data.Risk_x0020_RegisterListItem" },
"Category": { "results": ["Project","Technical"] }
}
Headers: X-HTTP-Method: MERGE; IF-MATCH: *; Accept/Content-Type: application/json;odata=verbose.

After saving, test and confirm both choices are selected on the item. Note: updates overwrite the entire selection, so always send the full set.

Best regards,

Valantis

✅ If this helped solve your issue, please Accept as Solution so others can find it quickly.

❤️ If it didn’t fully solve it but was still useful, please click “Yes” on “Was this reply helpful?” or leave a Like :).

🏷️ For follow-ups @Valantis.

📝 https://valantisond365.com/

Was this reply helpful? Yes No
Verified answer

Sayali-MSFT Microsoft Employee on at

Like
a
(2)

Report
Copy link

Link copied!

Hello @WM-02031008-0,

The root cause is that SharePoint multi-select Choice columns require a specific REST format ({ results: [] }), but Copilot Studio’s built-in tools cannot reliably send this structure. Due to schema coercion, the tool flattens inputs into simple arrays, which SharePoint rejects—resulting in 400 (bad request) or 502 (connector failure) errors. Even with correct prompting or schema guidance, this behavior cannot be overridden because the tool does not expose full payload control.

As a result, built-in Create/Update item actions are not reliable for multi-select fields. The only consistently working solution is to use Power Automate as a bridge, where you can explicitly send the correct { results: [] } payload via an HTTP request to SharePoint. Alternative options include switching to a single-select column (simpler but less flexible) or using a legacy string format hack (not recommended).

Final takeaway: This is a platform limitation, not a configuration issue. For multi-select SharePoint fields, Power Automate is the only robust and supported workaround today.

Was this reply helpful? Yes No