blend_path · Paint MCP: Risk & Policy

WHAT IT DOES

What blend_path does on Paint MCP

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

WHY IT NEEDS A POLICY

Why blend_path needs a policy

The tool creates or modifies the canvas by blending a path (likely a brush stroke with color mixing effects given the server's emphasis on 'oil paint mode' and 'color mixing'). This is reversible via clear_canvas or drawing over it, so it's Write rather than Destructive.

From the tool's definition Tool is part of a drawing/painting canvas system alongside write-oriented tools like draw_ellipse, draw_line, draw_path, draw_point, draw_rect, and flood_fill.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

blend_path Rate-limited

blend_path 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": {
    "blend_path": {
      "limits": [
        {
          "counter": "blend_path_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 Paint MCP, so you can run agents against it safely.

FAQ

Questions about blend_path

What does the blend_path tool do? +

blend_path. It is categorised as a Write tool in the Paint MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on blend_path? +

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

What risk level is blend_path? +

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

Can I rate-limit blend_path? +

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

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

blend_path is provided by the Paint MCP server (joeyballentine/paint-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.