update_ui_schema · Nocobase MCP: Risk & Policy

WHAT IT DOES

What update_ui_schema does on Nocobase

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

WHY IT NEEDS A POLICY

Why update_ui_schema needs a policy

This tool creates or modifies data reversibly. It updates UI schema configuration without deleting records or executing arbitrary code. The 'partial update' nature indicates data is changed but not destroyed. Given it affects UI presentation layer, it could have moderate impact if misused to alter application interface, but is reversible and doesn't execute commands, delete data, or move financial resources.

From the tool's definition Tool performs 'Patch an existing UI schema node by UID (partial update)' — a modification operation that changes UI schema data

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_ui_schema Rate-limited

update_ui_schema 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_ui_schema": {
      "limits": [
        {
          "counter": "update_ui_schema_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 Nocobase, so you can run agents against it safely.

FAQ

Questions about update_ui_schema

What does the update_ui_schema tool do? +

Patch an existing UI schema node by UID (partial update). It is categorised as a Write tool in the Nocobase 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_ui_schema? +

Register the Nocobase MCP server in PolicyLayer and add a rule for update_ui_schema: 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 Nocobase. Nothing to install.

What risk level is update_ui_schema? +

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

Can I rate-limit update_ui_schema? +

Yes. Add a rate_limit block to the update_ui_schema 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_ui_schema completely? +

Set action: deny in the PolicyLayer policy for update_ui_schema. 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_ui_schema? +

update_ui_schema is provided by the Nocobase MCP server (puguhsudarma/nocobase-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.