flip_vertical

THE RISK

Medium Risk

Why flip_vertical needs a policy

This tool modifies pixel art frame data but does not delete or permanently destroy content—the transformation can be undone by flipping again. It does not execute arbitrary code, read sensitive information, or perform financial operations. It is a Write operation because it creates or modifies data in a reversible manner, consistent with other layer/frame manipulation tools on this pixel art server.

From the tool's definition Tool flips a frame vertically, modifying the pixel art data. The description states it can apply to 'all frames', indicating the operation affects and transforms existing frame data. The operation is reversible (flipping twice returns to original state).

Documented attack patterns abuse exactly the kind of access flip_vertical gives an agent:

POLICY

How to control flip_vertical

PolicyLayer is an MCP gateway — it sits between your AI agents and Piskel MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for flip_vertical:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "flip_vertical": {
      "limits": [
        {
          "counter": "flip_vertical_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

flip_vertical 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.

Create a free account and register Piskel MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Piskel MCP Server tools

Destructive delete_project Delete a project Destructive remove_frame Remove a frame from all layers Destructive remove_layer Remove a layer from the project Destructive remove_palette_color Remove a color from a palette Write clear_frame Clear all pixels in a frame Write erase_pixel Erase pixels (set to transparent) Write hue_shift_recolor Recolor sprites by shifting hue. Reads PNGs from an input folder, shifts pixels in a sourc Write add_frame Add a new frame to a layer

All 45 Piskel MCP Server tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about flip_vertical

What does the flip_vertical tool do? +

Flip a frame vertically (mirror top-bottom). Supports applying to all frames. It is categorised as a Write tool in the Piskel 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 flip_vertical? +

Register the Piskel MCP Server MCP server in PolicyLayer and add a rule for flip_vertical: 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 Piskel MCP Server. Nothing to install.

What risk level is flip_vertical? +

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

Can I rate-limit flip_vertical? +

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

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

flip_vertical is provided by the Piskel MCP Server MCP server (yafeiaa/piskel-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Piskel MCP Server tool call.

Start from Piskel MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →