save_style_qml · QGIS MCP: Risk & Policy

WHAT IT DOES

What save_style_qml does on QGIS MCP

AI agents use save_style_qml 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 save_style_qml needs a policy

The tool creates or modifies a style file for a layer, which is a reversible write operation. It does not execute arbitrary code, delete data, move money, or trigger external operations beyond saving styling metadata. The blast radius is moderate because it could overwrite existing styles, but the operation is reversible by restoring from backups or resaving with different styles.

From the tool's definition Tool name 'save_style_qml' and description 'Save a layer' indicate the tool persists styling data to a QML (QGIS Markup Language) file. This modifies the project state by writing style information.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

save_style_qml Rate-limited

save_style_qml 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": {
    "save_style_qml": {
      "limits": [
        {
          "counter": "save_style_qml_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 save_style_qml

What does the save_style_qml tool do? +

Save a layer. 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 save_style_qml? +

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

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

Can I rate-limit save_style_qml? +

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

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

save_style_qml 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.