update_custom_field · Kommo MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_custom_field does on Kommo MCP Server

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

WHY IT NEEDS A POLICY

Why update_custom_field needs a policy

This tool modifies data reversibly—it updates custom field definitions such as renaming fields or adding enum values. These changes can be undone or corrected without permanent data loss. The blast radius is medium because incorrect custom field updates could affect data validation and display across the CRM system, impacting users and reports, but the changes themselves are not destructive or irreversible.

From the tool's definition update_custom_field: 'Update an existing custom field (e.g. rename it, or add new enums)' explicitly indicates modification of existing data structures within Kommo CRM.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

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.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Kommo MCP Server, so you can run agents against it safely.

FAQ

Questions about update_custom_field

What does the update_custom_field tool do? +

Update an existing custom field (e.g. rename it, or add new enums). It is categorised as a Write tool in the Kommo 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 Kommo 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 Kommo 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 Kommo MCP Server MCP server (wdavidce/kommo-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.