AI agents invoke rmx_scale to trigger actions in Glyphs. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
Although the tool description is empty, the name 'rmx_scale' strongly suggests a scaling/transformation operation on font data. Such operations are Execute-level because: (1) they trigger external operations (font transformation in GlyphsApp), (2) effects depend entirely on arguments (scale factors), and (3) while nominally reversible via undo, the tool itself performs an irreversible geometric transformation.
From the tool's definition Tool name 'rmx_scale' suggests a RoboFont/RemixTools function for scaling font metrics or glyphs. The server description states it 'read and write font data directly in GlyphsApp' with 'bidirectional, real-time' access.
Documented attack patterns abuse exactly the kind of access rmx_scale gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Glyphs, and nothing reaches the server without passing your rules. This is the rule we recommend for rmx_scale:
{
"version": "1",
"default": "deny",
"tools": {
"rmx_scale": {
"limits": [
{
"counter": "rmx_scale_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}rmx_scale stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
rmx_scale. It is categorised as a Execute tool in the Glyphs MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Glyphs MCP server in PolicyLayer and add a rule for rmx_scale: 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 Glyphs. Nothing to install.
rmx_scale is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the rmx_scale 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 rmx_scale. 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.
rmx_scale is provided by the Glyphs MCP server (nmassi/glyphs-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Glyphs, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
41 Glyphs tools catalogued and risk-classified — across an index of 43,000+ MCP servers.