generate_image · Posteverywhere MCP: Risk & Policy

WHAT IT DOES

What generate_image does on Posteverywhere

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

WHY IT NEEDS A POLICY

Why generate_image needs a policy

This tool creates and stores new media assets (generated images) in the user's media library. This is a reversible write operation — images can be deleted later (delete_media is a sibling tool). While it consumes credits (a financial resource), the primary action is content creation/storage, not financial transaction.

From the tool's definition Tool description states 'The image is saved to your media library' — a clear write/create operation that stores generated data persistently.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

generate_image Rate-limited

generate_image 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": {
    "generate_image": {
      "limits": [
        {
          "counter": "generate_image_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 Posteverywhere, so you can run agents against it safely.

FAQ

Questions about generate_image

What does the generate_image tool do? +

Generate an AI image from a text prompt on PostEverywhere. The image is saved to your media library and can be attached to posts via media_ids. Choose from 4 models: gemini-3-pro (default, balanced quality, 5 credits), nano-banana-pro (photorealism, 15 credits), ideogram-v2 (best for text-in-image, 8 credits), flux-schnell (fastest, 1 credit). Requires the. It is categorised as a Write tool in the Posteverywhere MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on generate_image? +

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

What risk level is generate_image? +

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

Can I rate-limit generate_image? +

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

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

generate_image is provided by the Posteverywhere MCP server (posteverywhere/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.