create_ellipse_mask · Bedrock Image MCP: Risk & Policy

WHAT IT DOES

What create_ellipse_mask does on Bedrock Image

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

WHY IT NEEDS A POLICY

Why create_ellipse_mask needs a policy

Mask creation is a Write operation—it generates new structured data (a mask) that modifies subsequent image processing steps. It is reversible (can be discarded or replaced) and has no permanent destructive effects. The empty description lowers confidence slightly, but the naming pattern and sibling tools clearly indicate this is part of an image editing workflow.

From the tool's definition Tool name 'create_ellipse_mask' indicates creation of a mask object. Sibling tools on this server (create_full_mask, create_rectangular_mask, inpaint_image, outpaint_image, remove_background) are image editing operations that create or modify image data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_ellipse_mask Rate-limited

create_ellipse_mask 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_ellipse_mask": {
      "limits": [
        {
          "counter": "create_ellipse_mask_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 Bedrock Image, so you can run agents against it safely.

FAQ

Questions about create_ellipse_mask

What does the create_ellipse_mask tool do? +

create_ellipse_mask. It is categorised as a Write tool in the Bedrock Image 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_ellipse_mask? +

Register the Bedrock Image MCP server in PolicyLayer and add a rule for create_ellipse_mask: 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 Bedrock Image. Nothing to install.

What risk level is create_ellipse_mask? +

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

Can I rate-limit create_ellipse_mask? +

Yes. Add a rate_limit block to the create_ellipse_mask 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_ellipse_mask completely? +

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

create_ellipse_mask is provided by the Bedrock Image MCP server (kalleeh/bedrock-image-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.