composite_images · Nano Banana MCP Server MCP: Risk & Policy

WHAT IT DOES

What composite_images does on Nano Banana MCP Server

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

WHY IT NEEDS A POLICY

Why composite_images needs a policy

This tool creates new composite image files by layering and blending existing images. While it modifies visual data, the operation is fundamentally a Write action (creating derived image artifacts). It is not Destructive because compositing is reversible—the original images remain unchanged, and the composite can be regenerated or deleted.

From the tool's definition Tool description states it enables 'Layer multiple images' and 'Create watermarks, overlays, or complex compositions' — operations that create or modify image files.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

composite_images Rate-limited

composite_images 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": {
    "composite_images": {
      "limits": [
        {
          "counter": "composite_images_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 Nano Banana MCP Server, so you can run agents against it safely.

FAQ

Questions about composite_images

What does the composite_images tool do? +

Layer multiple images with advanced blending modes and positioning. Create watermarks, overlays, or complex compositions. It is categorised as a Write tool in the Nano Banana MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on composite_images? +

Register the Nano Banana MCP Server MCP server in PolicyLayer and add a rule for composite_images: 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 Nano Banana MCP Server. Nothing to install.

What risk level is composite_images? +

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

Can I rate-limit composite_images? +

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

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

composite_images is provided by the Nano Banana MCP Server MCP server (lyalindotcom/nano-banana-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.