set_variable

THE RISK

Medium Risk

Why set_variable needs a policy

The set_variable tool performs reversible create/update operations on Figma design system variables and collections. This is a Write category action since it creates new data structures and modifies existing variables without permanently destroying data. Severity is medium because misuse could corrupt design systems affecting multiple files, but changes are reversible through Figma's undo/version history.

From the tool's definition Tool description states it will 'Create or update a variable in a Figma variable collection' and 'Creates the collection if collectionName is provided'. These are clearly write operations that create or modify data.

Documented attack patterns abuse exactly the kind of access set_variable gives an agent:

POLICY

How to control set_variable

PolicyLayer is an MCP gateway — it sits between your AI agents and Claude Talk to Figma MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for set_variable:

policy.json

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

set_variable 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.

Create a free account and register Claude Talk to Figma MCP — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Claude Talk to Figma MCP tools

Destructive delete_node Delete a node from Figma Destructive delete_page Delete a page from the current Figma document Execute load_font_async Load a font asynchronously in Figma Write apply_image_transform Adjust image position, scale, and rotation within node. Rotates the IMAGE inside the node, Write apply_variable_to_node Bind a variable to a node property in Figma. Call once per field — for multiple fields, ca Write boolean_operation Perform a boolean operation (union, subtract, intersect, exclude) on two or more nodes. Al Write clone_node Clone an existing node in Figma Write convert_to_frame Convert a group or shape node into a frame in Figma. Preserves position, size, visual prop

All 93 Claude Talk to Figma MCP tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about set_variable

What does the set_variable tool do? +

Create or update a variable in a Figma variable collection. Creates the collection if collectionName is provided and it doesn. It is categorised as a Write tool in the Claude Talk to Figma MCP 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_variable? +

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

What risk level is set_variable? +

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

Can I rate-limit set_variable? +

Yes. Add a rate_limit block to the set_variable 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_variable completely? +

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

set_variable is provided by the Claude Talk to Figma MCP server (arinspunk/claude-talk-to-figma-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Claude Talk to Figma MCP tool call.

Start from Claude Talk to Figma MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →