add_map_theme · QGIS MCP: Risk & Policy

WHAT IT DOES

What add_map_theme does on QGIS MCP

AI agents use add_map_theme 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_map_theme needs a policy

This tool creates and stores a new map theme configuration based on current layer visibility settings. While it does not delete data or execute arbitrary code, it modifies project state by adding a new theme artifact. This is reversible (themes can be deleted), so it falls under Write rather than Destructive.

From the tool's definition Tool name 'add_map_theme' and description 'Create a map theme from the current layer visibility state' indicates a create operation that persists configuration to the project.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_map_theme Rate-limited

add_map_theme 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_map_theme": {
      "limits": [
        {
          "counter": "add_map_theme_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 QGIS MCP, so you can run agents against it safely.

FAQ

Questions about add_map_theme

What does the add_map_theme tool do? +

Create a map theme from the current layer visibility state. 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_map_theme? +

Register the QGIS MCP server in PolicyLayer and add a rule for add_map_theme: 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_map_theme? +

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

Can I rate-limit add_map_theme? +

Yes. Add a rate_limit block to the add_map_theme 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_map_theme completely? +

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

add_map_theme 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.