vm_data_write · Victoriametrics MCP: Risk & Policy

WHAT IT DOES

What vm_data_write does on Victoriametrics

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

WHY IT NEEDS A POLICY

Why vm_data_write needs a policy

This tool writes data into a metrics database. While writing is generally reversible in concept, injecting incorrect or malicious metrics data into a monitoring/observability database can corrupt dashboards, alerts, and operational decision-making at scale. It does not delete data, so Destructive does not apply, but the blast radius of bad writes into a shared metrics store is high.

From the tool's definition 'Write data to the VM database' — explicitly writes data into the VictoriaMetrics time-series database

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vm_data_write Rate-limited

vm_data_write 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": {
    "vm_data_write": {
      "limits": [
        {
          "counter": "vm_data_write_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 Victoriametrics, so you can run agents against it safely.

FAQ

Questions about vm_data_write

What does the vm_data_write tool do? +

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

How do I enforce a policy on vm_data_write? +

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

What risk level is vm_data_write? +

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

Can I rate-limit vm_data_write? +

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

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

vm_data_write is provided by the Victoriametrics MCP server (@yincongcyincong/victoriametrics-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.