update_custom_field

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

SERVERinstantKOM MCP Server SOURCEinstantkom/mcp-server

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/instantkom-mcp-server/update-custom-field.md

WHAT IT DOES

What update_custom_field does on instantKOM MCP Server

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.

RISK

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 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.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs update_custom_field safely

PolicyLayer is an MCP gateway: it sits between your AI agents and instantKOM MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For update_custom_field, this is the rule to start with:

update_custom_field Rate-limited

update_custom_field stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

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

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect instantKOM MCP Server, apply this rule, and every update_custom_field call is checked against it from then on.

FAQ

Questions about update_custom_field

What does the update_custom_field tool do? +

Update a custom field definition. The field key cannot be changed. It is categorised as a Write tool in the instantKOM MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_custom_field? +

Register the instantKOM MCP Server MCP server in PolicyLayer and add a rule for update_custom_field: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches instantKOM MCP Server. Nothing to install.

What risk level is update_custom_field? +

update_custom_field is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit update_custom_field? +

Yes. Add a rate_limit block to the update_custom_field rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block update_custom_field completely? +

Set action: deny in the PolicyLayer policy for update_custom_field. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides update_custom_field? +

update_custom_field is provided by the instantKOM MCP Server MCP server (instantkom/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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