# update_custom_field

Update a custom field definition. The field key cannot be changed.

Agent View of the PolicyLayer registry record for `update_custom_field`. HTML page: https://policylayer.com/tools/instantkom-mcp-server/update-custom-field

## Facts

- Tool: `update_custom_field`
- Server: instantKOM MCP Server (`instantkom/mcp-server`) — https://policylayer.com/tools/instantkom-mcp-server.md
- Homepage: https://github.com/instantKOM/mcp-server
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "update_custom_field",
    "arguments": {}
  }
}
```

## Why update_custom_field is rated Medium

This tool modifies existing custom field definitions, which is a reversible write operation. It does not execute code, delete irreversibly, move funds, or trigger external side effects—it simply updates field metadata. The constraint that 'field key cannot be changed' further confirms it's a bounded modification.

From the tool's own definition: "Tool name is 'update_custom_field' and description states 'Update a custom field definition.' The verb 'update' combined with 'definition' indicates modification of metadata/configuration rather than deletion or execution of external processes."

## Use case

AI agents use update_custom_field to create or update resources in instantKOM MCP Server, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your instantKOM MCP Server environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches instantKOM MCP Server:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "update_custom_field": {
      "limits": [
        {
          "counter": "update_custom_field_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on instantKOM MCP Server (244)

- `bulk_delete_custom_fields` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/bulk-delete-custom-fields.md
- `delete_account` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-account.md
- `delete_api_key` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-api-key.md
- `delete_bot` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-bot.md
- `delete_bot_env_var` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-bot-env-var.md
- `delete_bot_env_var_value` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-bot-env-var-value.md
- `delete_bot_filter` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-bot-filter.md
- `delete_broadcast` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-broadcast.md
- `delete_broadcast_media` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-broadcast-media.md
- `delete_chat` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-chat.md
- `delete_contact` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-contact.md
- `delete_contact_custom_field_value` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-contact-custom-field-value.md
- `delete_custom_field` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-custom-field.md
- `delete_export` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-export.md
- `delete_feed` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-feed.md
- `delete_flow` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-flow.md
- `delete_flow_edge` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-flow-edge.md
- `delete_flow_node` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-flow-node.md
- `delete_message` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-message.md
- `delete_message_media` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-message-media.md
- `delete_object_folder` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-object-folder.md
- `delete_poll` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-poll.md
- `delete_poll_option` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-poll-option.md
- `delete_qr_code` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-qr-code.md
- `delete_segmentation` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-segmentation.md
- `delete_short_link` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-short-link.md
- `delete_super_widget` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-super-widget.md
- `delete_tag` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-tag.md
- `delete_team_member_by_id` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-team-member-by-id.md
- `delete_template` — Destructive — https://policylayer.com/tools/instantkom-mcp-server/delete-template.md
- …and 214 more: https://policylayer.com/tools/instantkom-mcp-server.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=instantkom-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/instantkom-mcp-server