Duplicate a glyph (all layers and paths) under a new name.
AI agents use duplicate_glyph to create or update resources in Glyphs — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Glyphs environment.
This tool creates a new glyph by copying an existing one. It is a reversible write operation — it does not delete or overwrite existing data, but rather creates a new named copy. Misuse could clutter the font with unwanted glyphs, but no data is irreversibly destroyed.
From the tool's definition Duplicate a glyph (all layers and paths) under a new name.
Documented attack patterns abuse exactly the kind of access duplicate_glyph 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 duplicate_glyph:
{
"version": "1",
"default": "deny",
"tools": {
"duplicate_glyph": {
"limits": [
{
"counter": "duplicate_glyph_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}duplicate_glyph 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.
Free to start. No card required.
Duplicate a glyph (all layers and paths) under a new name. It is categorised as a Write tool in the Glyphs MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Glyphs MCP server in PolicyLayer and add a rule for duplicate_glyph: 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.
duplicate_glyph is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the duplicate_glyph 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 duplicate_glyph. 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.
duplicate_glyph 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.