add_layout_scalebar · QGIS MCP: Risk & Policy

WHAT IT DOES

What add_layout_scalebar does on QGIS MCP

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

WHY IT NEEDS A POLICY

Why add_layout_scalebar needs a policy

This tool creates a new visual component (scale bar) in a print layout, which is a reversible modification of the project state. It does not execute arbitrary code, delete data, or trigger financial transactions. The 'Add' verb and the context of layout management (similar to sibling tools like add_layout_label, add_layout_legend) confirm this is a Write operation.

From the tool's definition Tool name 'add_layout_scalebar' and description 'Add a scale bar to a print layout' indicate creation/modification of layout elements within a QGIS project.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_layout_scalebar Rate-limited

add_layout_scalebar 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": {
    "add_layout_scalebar": {
      "limits": [
        {
          "counter": "add_layout_scalebar_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches QGIS MCP, so you can run agents against it safely.

FAQ

Questions about add_layout_scalebar

What does the add_layout_scalebar tool do? +

Add a scale bar to a print layout, linked to a map item. style e.g. It is categorised as a Write tool in the QGIS 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 add_layout_scalebar? +

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

What risk level is add_layout_scalebar? +

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

Can I rate-limit add_layout_scalebar? +

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

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

add_layout_scalebar is provided by the QGIS MCP server (nkarasiak/qgis-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.