get-series · Prometheus MCP: Risk & Policy

WHAT IT DOES

What get-series does on Prometheus

AI agents call get-series to retrieve information from Prometheus without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

WHY IT NEEDS A POLICY

Why get-series needs a policy

This tool performs a read-only discovery/lookup operation against Prometheus to identify which time-series exist based on label matching criteria. It retrieves data without side effects, aligning with the Read category. Severity is low because retrieving metric metadata poses minimal risk even if misused — it exposes no secrets and cannot modify system state.

From the tool's definition Tool is named 'get-series' with description 'Find series by label matchers' — a query operation that retrieves metadata about time-series matching specified labels from Prometheus. No mutation, deletion, or execution of arbitrary code occurs.

Attacks that exploit this kind of access

Questions about get-series

What does the get-series tool do? +

Find series by label matchers. It is categorised as a Read tool in the Prometheus MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on get-series? +

Register the Prometheus MCP server in PolicyLayer and add a rule for get-series: 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. Nothing to install.

What risk level is get-series? +

get-series is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit get-series? +

Yes. Add a rate_limit block to the get-series 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 get-series completely? +

Set action: deny in the PolicyLayer policy for get-series. 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 get-series? +

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