Fill a rectangular region with a solid color. Parameters: - x, y: Top-left corner - width, height: Rectangle dimensions - color: Fill color (CSS name, hex, or rgb() string) - layer_name: Target layer; defaults to active layer - image_index: Target image index (default 0) Returns status dict.
AI agents use fill_rectangle 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.
The fill_rectangle tool creates or modifies image data (pixels) within a specified rectangular area. This is a Write operation because: (1) it changes existing image content reversibly, (2) the user can undo the operation in GIMP, and (3) it does not delete data or execute arbitrary code. It is not Destructive because the operation is reversible and does not permanently erase information.
From the tool's definition Tool fills a rectangular region with a solid color by modifying image data. Description states it modifies layer content and returns status dict. This is a reversible modification operation that changes pixel data within GIMP.
Documented attack patterns abuse exactly the kind of access fill_rectangle 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 fill_rectangle:
{
"version": "1",
"default": "deny",
"tools": {
"fill_rectangle": {
"limits": [
{
"counter": "fill_rectangle_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}fill_rectangle 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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Fill a rectangular region with a solid color. Parameters: - x, y: Top-left corner - width, height: Rectangle dimensions - color: Fill color (CSS name, hex, or rgb() string) - layer_name: Target layer; defaults to active layer - image_index: Target image index (default 0) 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 fill_rectangle: 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.
fill_rectangle 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 fill_rectangle 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 fill_rectangle. 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.
fill_rectangle 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.