---
title: "Update Custom Field"
description: "Update a specific custom field by ID."
---

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

# Update Custom Field

Use the Speak AI MCP server tool `update_field` to update a specific custom field by
ID.

## What does it do?

Update a specific custom field by ID. `name` must always be supplied (the server
replaces the field config).

## Parameters

`update_field` takes 10 parameters, 2 of them required.

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `id` | string | Yes | Unique identifier of the field |
| `name` | string | Yes | Display name for the field |
| `type` | string | No | Field type |
| `description` | string | No | Optional description for the field |
| `prompt` | string | No | AI prompt used to auto-populate the field |
| `allowedValues` | array of string | No | Allowed values for select/multi-select field types |
| `allowedValuesMode` | enum | No | Whether one or multiple allowed values can be selected |
| `otherValues` | boolean | No | Whether values outside allowedValues are permitted |
| `notApplicableValues` | string | No | Value(s) treated as not-applicable |
| `privacyMode` | string | No | Privacy mode for the field |

## Behaviour

The Speak AI MCP server publishes these behaviour hints for `update_field`.

- Can change data in your workspace.
- Can delete or overwrite data. Use with care.
- Repeating an identical call is safe.
- Stays inside Speak AI. Does not reach other systems.

## Related

- [Custom fields](/mcp/tools/custom-fields/) lists the rest of the Custom fields
  category.
- [Tool reference](/mcp/tools/) lists every Speak AI MCP server tool.
- [MCP server](/mcp/) covers setup, supported clients, and what agents can do once
  connected.

Source: https://docs.speakai.co/mcp/tools/custom-fields/update_field/index.mdx