create_thumbnail · Graphics MCP: Risk & Policy

WHAT IT DOES

What create_thumbnail does on Graphics

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

WHY IT NEEDS A POLICY

Why create_thumbnail needs a policy

Creating a thumbnail generates a new image file (reversible write operation). Severity is medium because the blast radius is limited to image file creation—no deletion, no financial impact, no code execution. Confidence is 0.85 rather than higher due to empty description, but the tool name and server purpose provide sufficient context.

From the tool's definition Tool name 'create_thumbnail' indicates creation of a new image file; sibling tools (apply_filter, convert_image, crop_image, etc.) all perform image transformations that modify or create new image data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_thumbnail Rate-limited

create_thumbnail 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": {
    "create_thumbnail": {
      "limits": [
        {
          "counter": "create_thumbnail_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Graphics, so you can run agents against it safely.

FAQ

Questions about create_thumbnail

What does the create_thumbnail tool do? +

create_thumbnail. It is categorised as a Write tool in the Graphics MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_thumbnail? +

Register the Graphics MCP server in PolicyLayer and add a rule for create_thumbnail: 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 Graphics. Nothing to install.

What risk level is create_thumbnail? +

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

Can I rate-limit create_thumbnail? +

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

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

create_thumbnail is provided by the Graphics MCP server (lesleslie/graphics-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.