> ## Documentation Index
> Fetch the complete documentation index at: https://docs.automate.ax/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Automate.ax automations are TypeScript programs.
> Use Bun for installation and command examples.
> Use Automate.ax for the product name and automate.ax for the package, CLI, and domain.
> Treat documented public APIs as current; do not invent transitional or deprecated names.

# Set card Custom Field value

> Set one typed Custom Field value on a Trello card.

`trello.setCardCustomFieldValue` sets one typed value on a card.

```ts automations/set-trello-card-custom-field-value.automation.ts theme={null}
import { automation, onDashboardRun } from "automate.ax"
import { trello } from "automate.ax/trello"

export default automation("Set Trello card estimate", () => {
  onDashboardRun({ title: "Set Trello card estimate" })
  trello.setCardCustomFieldValue({
    card: "card-id",
    customFieldId: "custom-field-id",
    value: { number: "8", type: "number" },
  })
})
```

Provide `card`, `customFieldId`, and a value matching the field definition:

* `{ type: "checkbox", checked: boolean }`
* `{ type: "date", date: Date | ISO 8601 timestamp with an offset }`
* `{ type: "list", optionId: string }`
* `{ type: "number", number: string }`
* `{ type: "text", text: string }`

Number values remain strings so Trello's decimal representation is preserved. Optional second argument `{ account }` selects a Trello binding. Returns `Signal<{ cardId: string; customFieldId: string; value: TrelloCustomFieldValue }>`.