delete_kerning_pair

THE RISK

Critical Risk

Why delete_kerning_pair needs a policy

This tool permanently removes kerning pair data from a font file. Kerning pairs are fundamental font metrics that control spacing between character combinations. Deletion cannot be undone through the tool itself and represents irreversible data loss.

From the tool's definition Tool name is 'delete_kerning_pair' with description 'Delete a kerning pair.' The verb 'delete' indicates irreversible removal of data.

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

POLICY

How to control delete_kerning_pair

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 delete_kerning_pair:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "delete_kerning_pair"
  ]
}

delete_kerning_pair disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

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

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

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All 41 Glyphs tools →

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Go deeper

Critical-risk tools in Glyphs → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about delete_kerning_pair

What does the delete_kerning_pair tool do? +

Delete a kerning pair. It is categorised as a Destructive tool in the Glyphs MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on delete_kerning_pair? +

Register the Glyphs MCP server in PolicyLayer and add a rule for delete_kerning_pair: 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.

What risk level is delete_kerning_pair? +

delete_kerning_pair is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit delete_kerning_pair? +

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

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

delete_kerning_pair 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.

Enforce policy on every Glyphs tool call.

Start from Glyphs, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →