libi.upload_font

SERVERLibi SOURCENagellabs/libi

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/libi/libi.upload-font.md

WHAT IT DOES

What libi.upload_font does on Libi

AI agents use libi.upload_font to create or update resources in Libi, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Libi environment.

RISK

Why libi.upload_font is rated Medium

Uploads and stores font files reversibly; no deletion, execution, or financial impact.

From the tool's definition Upload a custom font file, stores it, return fontFileId

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs libi.upload_font safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Libi, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For libi.upload_font, this is the rule to start with:

libi.upload_font Rate-limited

libi.upload_font 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "libi.upload_font": {
      "limits": [
        {
          "counter": "libi.upload_font_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Libi, apply this rule, and every libi.upload_font call is checked against it from then on.

FAQ

Questions about libi.upload_font

What does the libi.upload_font tool do? +

Upload a custom font file (.ttf/.otf/.woff2) and return a fontFileId usable on text overlays. Reads the file from the local filesystem, infers its type from the extension, and stores it. Set the returned fontFileId on a text overlay (via libi.add_overlay / libi.update_overlay) to render that typeface in the preview and ffmpeg export. It is categorised as a Write tool in the Libi MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on libi.upload_font? +

Register the Libi MCP server in PolicyLayer and add a rule for libi.upload_font: 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 Libi. Nothing to install.

What risk level is libi.upload_font? +

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

Can I rate-limit libi.upload_font? +

Yes. Add a rate_limit block to the libi.upload_font 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 libi.upload_font completely? +

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

libi.upload_font is provided by the Libi MCP server (Nagellabs/libi). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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Guides

Govern customer-ops agents →Argument validation →Scoped token →