Get all Symbol Masters in the Sketch document
AI agents call getSymbolMasters to retrieve information from Sketch without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves symbol master definitions from a Sketch document without creating, modifying, deleting, or executing any code. It is a passive read operation that returns design information. The blast radius is minimal—an AI agent cannot cause harm by retrieving this metadata. It belongs in the Read category with low severity.
From the tool's definition Tool name 'getSymbolMasters' and description 'Get all Symbol Masters in the Sketch document' indicate retrieval of design metadata with no modification or execution. This is a query operation on a Sketch design file.
Documented attack patterns abuse exactly the kind of access getSymbolMasters gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Sketch, and nothing reaches the server without passing your rules. This is the rule we recommend for getSymbolMasters:
{
"version": "1",
"default": "deny",
"tools": {
"getSymbolMasters": {}
}
}getSymbolMasters is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get all Symbol Masters in the Sketch document. It is categorised as a Read tool in the Sketch MCP Server, which means it retrieves data without modifying state.
Register the Sketch MCP server in PolicyLayer and add a rule for getSymbolMasters: 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 Sketch. Nothing to install.
getSymbolMasters is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the getSymbolMasters 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.
Set action: deny in the PolicyLayer policy for getSymbolMasters. 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.
getSymbolMasters is provided by the Sketch MCP server (mater1996/sketch-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Sketch, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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17 Sketch tools catalogued and risk-classified — across an index of 43,000+ MCP servers.