color_add_rgb · Open Brush MCP Server MCP: Risk & Policy

WHAT IT DOES

What color_add_rgb does on Open Brush MCP Server

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

WHY IT NEEDS A POLICY

Why color_add_rgb needs a policy

The tool creates or modifies drawing state (current color) within Open Brush without destroying data or executing arbitrary code. Color adjustments in a paint program are reversible changes, fitting the Write category. The blast radius is minimal since it only affects the active drawing session's color palette and can be easily undone.

From the tool's definition Tool name is 'color_add_rgb' and description states it 'Adds values to current color (RGB)' — this modifies color state in the Open Brush application, a reversible operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

color_add_rgb Rate-limited

color_add_rgb 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": {
    "color_add_rgb": {
      "limits": [
        {
          "counter": "color_add_rgb_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 Open Brush MCP Server, so you can run agents against it safely.

FAQ

Questions about color_add_rgb

What does the color_add_rgb tool do? +

Adds values to current color (RGB). It is categorised as a Write tool in the Open Brush 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 color_add_rgb? +

Register the Open Brush MCP Server MCP server in PolicyLayer and add a rule for color_add_rgb: 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 Open Brush MCP Server. Nothing to install.

What risk level is color_add_rgb? +

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

Can I rate-limit color_add_rgb? +

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

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

color_add_rgb is provided by the Open Brush MCP Server MCP server (moz411/openbrush-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.