Invert all colors in a layer (create a negative). Parameters: - image_index: Target image index (default 0) - layer_name: Layer to invert; defaults to active layer Returns status dict.
AI agents use invert_colors to create or update resources in Gimp — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Gimp environment.
This tool modifies image data by inverting colors on a specified layer. While the operation is reversible (can be inverted again), it directly alters the visual content of the image. This is a Write operation rather than Read (retrieves data unchanged), Execute (runs arbitrary code), or Destructive (permanent loss).
From the tool's definition Tool description states 'Invert all colors in a layer' and 'Returns status dict', indicating it modifies image data. The parameters allow targeting specific layers within an image.
Documented attack patterns abuse exactly the kind of access invert_colors gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Gimp, and nothing reaches the server without passing your rules. This is the rule we recommend for invert_colors:
{
"version": "1",
"default": "deny",
"tools": {
"invert_colors": {
"limits": [
{
"counter": "invert_colors_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}invert_colors 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.
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Invert all colors in a layer (create a negative). Parameters: - image_index: Target image index (default 0) - layer_name: Layer to invert; defaults to active layer Returns status dict. It is categorised as a Write tool in the Gimp MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Gimp MCP server in PolicyLayer and add a rule for invert_colors: 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 Gimp. Nothing to install.
invert_colors is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the invert_colors 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.
Set action: deny in the PolicyLayer policy for invert_colors. 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.
invert_colors is provided by the Gimp MCP server (maorcc/gimp-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Gimp, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
79 Gimp tools catalogued and risk-classified — across an index of 43,000+ MCP servers.