prom_range · Prometheus MCP Server MCP: Risk & Policy

WHAT IT DOES

What prom_range does on Prometheus MCP Server

AI agents invoke prom_range to trigger actions in Prometheus MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why prom_range needs a policy

Executing a PromQL range query is an active operation that runs user-supplied query expressions against the Prometheus backend. While Prometheus queries are read-only by nature (no data modification), 'Execute' is more appropriate than 'Read' because the tool runs arbitrary query code whose computational cost and behavior depend on the arguments supplied (e.g., expensive queries can overload the server).

From the tool's definition "Execute a PromQL range query" — the tool runs an arbitrary PromQL expression against Prometheus over a time range.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

prom_range Rate-limited

prom_range stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "prom_range": {
      "limits": [
        {
          "counter": "prom_range_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about prom_range

What does the prom_range tool do? +

Execute a PromQL range query. It is categorised as a Execute tool in the Prometheus MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on prom_range? +

Register the Prometheus MCP Server MCP server in PolicyLayer and add a rule for prom_range: 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 Prometheus MCP Server. Nothing to install.

What risk level is prom_range? +

prom_range is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit prom_range? +

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

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

prom_range is provided by the Prometheus MCP Server MCP server (yanmxa/prometheus-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.