Configuration

This server can be configured via environment variables and a few CLI flags. CLI flags take precedence over environment variables for the same setting.

Precedence

CLI flag > environment variable > built-in default

Quick reference

Name	Type	Default	CLI flag	Description
PROMETHEUS_URL	string (URL)	http://localhost:9090	--prometheus-url	Base URL of your Prometheus server
PROMETHEUS_TIMEOUT	integer (seconds)	10	—	HTTP request timeout
PROMETHEUS_RETRIES	integer	3	—	Number of retries for Prometheus API calls
PROMETHEUS_RETRY_BACKOFF_MS	integer (ms)	500	—	Time to wait between retries
PROMETHEUS_MIN_INTERVAL_MS	integer (ms)	none	—	If set, enforces a minimum interval between query requests (basic rate limit)
PROMETHEUS_CACHE_TTL_SECS	integer (seconds)	none	—	TTL for simple in-process caches (list metrics and label values)
PROMETHEUS_USERNAME	string	none	--prometheus-username	Basic auth username
PROMETHEUS_PASSWORD	string	none	--prometheus-password	Basic auth password
—	boolean	false	--mcp	Start MCP server over stdio
—	boolean	false	--metrics-exporter	Enable internal Prometheus metrics at /metrics
—	integer (port)	9091	--metrics-port	Port to expose the internal /metrics endpoint when enabled

::: note Advanced HTTP behavior (timeout, retries, backoff, rate limiting) is environment-only. Caches are per-process and reset on restart. :::

Basic Authentication

You can configure Basic Auth using either environment variables or CLI flags.

env vars

export PROMETHEUS_URL=https://prom.example.com
export PROMETHEUS_USERNAME=api
export PROMETHEUS_PASSWORD=secret
prometheus-mcp --mcp

CLI flags

prometheus-mcp --mcp \
  --prometheus-url https://prom.example.com \
  --prometheus-username api \
  --prometheus-password secret

Docker

docker run --rm -it \
  -e PROMETHEUS_URL=https://prom.example.com \
  -e PROMETHEUS_USERNAME=api \
  -e PROMETHEUS_PASSWORD=secret \
  prometheus-mcp:latest --mcp

Security

Avoid committing secrets. Prefer environment variables, Docker secrets, or a host secret manager.

Metrics Exporter

If enabled with --metrics-exporter, the binary exposes its own Prometheus metrics at /metrics on --metrics-port ( default 9091).

prometheus-mcp --mcp --metrics-exporter --metrics-port 9091
curl -s http://localhost:9091/metrics | head