query_loki · Grafana MCP Server MCP: Risk & Policy

WHAT IT DOES

What query_loki does on Grafana MCP Server

AI agents invoke query_loki to trigger actions in Grafana 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 query_loki needs a policy

The tool runs an active query against a Loki datasource. While primarily read-oriented in intent, it executes arbitrary LogQL queries against an external system, placing it in the Execute category. Misuse could involve crafting queries that cause excessive load or expose sensitive log data at scale.

From the tool's definition Execute a LogQL query against a Loki datasource to search logs

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

query_loki Rate-limited

query_loki 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": {
    "query_loki": {
      "limits": [
        {
          "counter": "query_loki_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 Grafana MCP Server, so you can run agents against it safely.

FAQ

Questions about query_loki

What does the query_loki tool do? +

Execute a LogQL query against a Loki datasource to search logs. It is categorised as a Execute tool in the Grafana 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 query_loki? +

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

What risk level is query_loki? +

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

Can I rate-limit query_loki? +

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

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

query_loki is provided by the Grafana MCP Server MCP server (quanticsoul4772/grafana-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.