vehicles · Personal Brain MCP: Risk & Policy

WHAT IT DOES

What vehicles does on Personal Brain

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

WHY IT NEEDS A POLICY

Why vehicles needs a policy

The tool enables creation and modification of vehicle management data (service records, mileage tracking, registration notes), which constitutes Write-category functionality. Severity is low because misuse would affect only personal vehicle records with no financial, destructive, or operational consequences (e.g., an AI agent cannot actually service a vehicle or commit insurance fraud through this data interface).

From the tool's definition Tool description states 'Manage vehicles' and 'Tracks mileage, insurance, registration, inspections' — indicating creation and modification of vehicle records and service history data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vehicles Rate-limited

vehicles 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": {
    "vehicles": {
      "limits": [
        {
          "counter": "vehicles_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 Personal Brain, so you can run agents against it safely.

FAQ

Questions about vehicles

What does the vehicles tool do? +

Manage vehicles (cars, trucks, mowers, ATVs) + service history. Tracks mileage, insurance, registration, inspections. due_services lists upcoming maintenance by date or mileage. It is categorised as a Write tool in the Personal Brain MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on vehicles? +

Register the Personal Brain MCP server in PolicyLayer and add a rule for vehicles: 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 Personal Brain. Nothing to install.

What risk level is vehicles? +

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

Can I rate-limit vehicles? +

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

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

vehicles is provided by the Personal Brain MCP server (phantomts/personal-brain-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.