Feature request: Trello MCP needs to support updating custom field values, not just reading them
Hi Trello team,
I was pleased to see custom field support introduced in the September 28 MCP update, but I have to say I'm quite disappointed that, more than a month later, we still cannot update custom field values on existing cards.
Being able to read custom fields is useful, of course, but without the ability to modify them, the functionality feels only half implemented.
For example, I use a dropdown custom field to manage task priorities (Urgent, High, Medium, Low, etc.). ChatGPT can identify the field, retrieve its available options and read the current value, but it cannot actually change a card's priority.
This significantly limits the usefulness of Trello MCP for task management and automation.
What's particularly surprising is that the trelloWriteCard tool already exposes the customFieldId and customFieldValue parameters, but the set_custom_field_value action is missing from its supported actions. Any attempt to use it fails during schema validation.
I've also tried reconnecting and reauthorising Trello in ChatGPT, without success.
Considering that the Trello REST API has supported updating custom field values for years, I find it difficult to understand why such an essential capability is still missing from the official MCP.
Reading custom fields was a welcome first step, but surely the ability to update them should be a priority rather than something left for an unspecified future release.
Could the Trello team confirm whether this is actively being developed and when we can realistically expect it to become available?
Thanks!
