set_instance_overrides · MCP Figma MCP: Risk & Policy

WHAT IT DOES

What set_instance_overrides does on MCP Figma

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

WHY IT NEEDS A POLICY

Why set_instance_overrides needs a policy

The tool creates or modifies design data within Figma by applying overrides to component instances and swapping components. These are Write-category operations because they alter existing design elements.

From the tool's definition 'Apply previously copied overrides to selected component instances. Target instances will be swapped to the source component and all copied override properties will be applied.' - This tool modifies component instances by applying overrides and swapping…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_instance_overrides Rate-limited

set_instance_overrides 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": {
    "set_instance_overrides": {
      "limits": [
        {
          "counter": "set_instance_overrides_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 MCP Figma, so you can run agents against it safely.

FAQ

Questions about set_instance_overrides

What does the set_instance_overrides tool do? +

Apply previously copied overrides to selected component instances. Target instances will be swapped to the source component and all copied override properties will be applied. It is categorised as a Write tool in the MCP Figma MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_instance_overrides? +

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

What risk level is set_instance_overrides? +

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

Can I rate-limit set_instance_overrides? +

Yes. Add a rate_limit block to the set_instance_overrides 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 set_instance_overrides completely? +

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

set_instance_overrides is provided by the MCP Figma MCP server (yelowflash09/figma_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.