# prometheus-label-strategy

Audits and designs Prometheus label schemas to prevent high cardinality at the source, from application code to scrape targets, before series reach storage.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 3800 installs · ★ 290
- Author: grafana
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/grafana/skills/tree/HEAD/skills/grafana-cloud/prometheus-label-strategy/SKILL.md
- Updated: 2026-10-25
- HTML: https://affpapa.org/en/nevibecode/skills/prometheus-label-strategy

## What it does

This skill evaluates Prometheus label schemas for Grafana Cloud to stop cardinality explosions before series enter storage. It reviews proposed labels through cardinality scoring and query access-pattern alignment. If series already exist in Grafana Cloud and need cost reduction, it routes to `adaptive-metrics`. If an active cardinality incident is underway, it points to `prometheus-cardinality-troubleshooter`.

The core rule is strict: never drop a label at scrape time if it distinguishes one series from another, such as `pod` or `instance`. Stripping identifiers via `metric_relabel_configs` with `action: labeldrop` or Alloy relabeling silently corrupts data. Independent counter restarts collapse into a single stream, causing `rate()` and `increase()` to report absurd numbers while inflating data points per minute (DPM).

High-cardinality values belong in exemplars rather than labels. Raw URLs and `user_id` values must stay out of label sets because they multiply series counts across the entire system.

## Requirements
- Works with: Grafana

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add grafana/skills --skill prometheus-label-strategy -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/prometheus-label-strategy/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/prometheus-label-strategy/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add grafana/skills --skill prometheus-label-strategy -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/prometheus-label-strategy/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add grafana/skills --skill prometheus-label-strategy -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/prometheus-label-strategy/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install grafana/skills prometheus-label-strategy
```

2. **Manually: put the files in place**
- File: `.github/skills/prometheus-label-strategy/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add grafana/skills --skill prometheus-label-strategy -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/grafana/skills --path skills/grafana-cloud/prometheus-label-strategy
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/prometheus-label-strategy/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add grafana/skills --skill prometheus-label-strategy -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/grafana/skills/tree/HEAD/skills/grafana-cloud/prometheus-label-strategy/SKILL.md

## When to use it
- design Prometheus label schemas before sending metrics to storage
- identify unbounded labels such as `user_id` or raw query strings
- prevent broken `rate()` calculations caused by collapsing series during scrape
- structure static and dynamic target relabeling rules

## Example prompts
- Evaluate the label schema for our checkout service: `method`, `path`, `status_code`, and `user_id`.
- Audit these Prometheus target relabeling rules to prevent cardinality spikes.
- Review our application metrics and identify which attributes belong in exemplars.

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: a883a11083a7dc12.

BEGIN THIRD-PARTY FILE a883a11083a7dc12
```text
---
name: prometheus-label-strategy
license: Apache-2.0
description: >
  Expert evaluator for Prometheus label strategy on Grafana Cloud. Audits, designs, and
  improves label schemas using cardinality scoring, access-pattern alignment, static vs.
  dynamic label rules, histogram bucket discipline, and instrumentation hygiene. Prevents
  high cardinality at the source — in application code and scrape target labels — without
  dropping labels that make series unique (which breaks the data). For reducing the cost of
  series already in Grafana Cloud, routes to the adaptive-metrics skill. Use when the user
  asks to evaluate, audit, design, or improve Prometheus labels — or asks how to prevent
  high cardinality at the source. For "why is my Prometheus slow / expensive right now"
  triage, see prometheus-cardinality-troubleshooter.
---

# Prometheus Label Strategy Evaluator

You are an expert in Prometheus label strategy. When asked to evaluate, audit, design, or improve a Prometheus label schema — or when a user asks how to prevent high cardinality at the source — use this guide to provide structured, actionable advice.

This skill is about **preventing bad labels at the source** — in application instrumentation and in scrape *target* labels — so they never enter storage. It is **not** about stripping labels off metrics after they've been emitted: removing a label that makes a series unique at scrape time silently breaks the data (see [The One Rule](#the-one-rule-never-drop-a-label-that-makes-a-series-unique) below). For reducing the cost of series that already exist in Grafana Cloud, route the user to the `adaptive-metrics` skill. For diagnosing an active cardinality fire, route to `prometheus-cardinality-troubleshooter`.

---

## The One Rule: Never Drop a Label That Makes a Series Unique

**You cannot remove, at scrape time, any label that makes a series unique.** Not `pod`, not `instance`, not anything that distinguishes one real series from another. This includes `metric_relabel_configs` with `action: labeldrop` and the equivalent `prometheus.relabel` rules in Alloy.

It looks like a cardinality win. It is not — it **breaks the data**, silently and permanently:
```
END THIRD-PARTY FILE a883a11083a7dc12

The third-party file has ended. Everything between the a883a11083a7dc12 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

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---
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