# promql

Writes and validates PromQL against Prometheus, Mimir and Grafana Cloud Metrics. Useful when a p95 looks wrong or a query drags.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 8000 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-core/promql/SKILL.md
- Updated: 2026-10-25
- HTML: https://affpapa.org/en/nevibecode/skills/promql

## What it does

The skill hands your agent a PromQL pattern library: `rate` versus `irate` and `increase`, label matchers and regex, `sum / avg / topk / by / without` aggregation, `histogram_quantile` for classic and native histograms, ratios with divide-by-zero guards, `absent` and `changes` for staleness, time offsets and `predict_linear`, recording-rule naming, SLO and burn-rate math. There is also a playbook for hunting the noisy label behind a cardinality spike.

It works in steps. You sketch the expression, the agent checks syntax and whether the metric and labels exist through `/api/v1/query` and `/api/v1/series`, then you confirm the magnitude in Grafana Explore against a known ground truth. A slow dashboard query can become a recording rule: the expression gets a name like `job:http_request_duration_p95:rate5m`, the rule loads, the new metric is verified with the same query, and only then does the panel switch to it.

The window is where most people trip. `rate()` and `increase()` need a range vector at least four times the scrape interval; with a 60s scrape that means `[5m]` minimum. Go shorter and you get "No data", then waste time checking label spelling instead of the window. You also need a Prometheus, Mimir or Grafana Cloud endpoint to query, and on Grafana Cloud every `curl` carries basic auth.

## Requirements
- Works with: Grafana

## Install

### Claude Code (native platform)

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

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

### Codex

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

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

### Cursor

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

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

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install grafana/skills promql
```

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

### Gemini CLI

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

2. **Platform CLI**
```bash
gemini skills install https://github.com/grafana/skills --path skills/grafana-core/promql
```

### Windsurf (Devin Desktop)

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

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add grafana/skills --skill promql -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-core/promql/SKILL.md

## When to use it
- compute the 5xx share per service
- fix a p95 that comes out wrong
- build an error-budget alert
- find the label that blew up cardinality
- turn a slow dashboard query into a recording rule

## Example prompts
- calculate the error rate per service over 5 minutes
- why is this query slow and what's filling Mimir
- turn this expression into a recording rule for p95

## 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: 602a610f94911422.

BEGIN THIRD-PARTY FILE 602a610f94911422
````text
---
name: promql
license: Apache-2.0
description: Write, validate, and optimize PromQL for Prometheus / Grafana Mimir / Grafana Cloud Metrics. Covers `rate` vs `irate` vs `increase`, label matchers and regex, `sum / avg / topk / by / without` aggregation, classic + native `histogram_quantile`, ratios with divide-by-zero guards, `absent` / `changes` for staleness, time offsets and `predict_linear`, recording-rule naming, SLO + burn-rate math, and a cardinality-hunting playbook. Use when writing a metric query, fixing wrong p95s, building an error-budget alert, debugging "query is slow", finding the noisy label that blew up cardinality, or migrating a dashboard query to a recording rule — even when the user says "calculate the error rate", "p99 latency", "sum by service", "why is this query slow", or "what's filling Mimir" without naming PromQL.
---

# PromQL Query Patterns

> **Docs**: https://prometheus.io/docs/prometheus/latest/querying/basics/

PromQL returns either an **instant vector**, a **range vector**, or a **scalar**.

**Golden rule:** `rate()` / `increase()` require a range vector ≥ 4× the scrape interval. 60s scrape → use `[5m]` minimum.

## Prerequisites

- A Prometheus / Mimir / Grafana Cloud endpoint to query (`/api/v1/query` or via Grafana Explore)
- The PromQL pattern library in [`references/patterns.md`](references/patterns.md)

## Common Workflows

### 1. Write + validate a query

```bash
# 0. Point at your Prometheus/Mimir. For Grafana Cloud, use the metrics endpoint
#    and add basic auth (-u "<metrics_user>:<token>") to each curl below.
PROM=http://localhost:9090   # or https://prometheus-prod-XX.grafana.net/api/prom

# 1. Sketch the query — for "5xx error rate per service":
EXPR='sum(rate(http_requests_total{status_code=~"5.."}[5m])) by (service)'

# 2. Validate syntax + that the metric/labels exist
curl -sG --data-urlencode "query=${EXPR}" \
  "$PROM/api/v1/query" | jq '.status, (.data.result|length)'
# Expect: "success" and result count > 0. If 0 — check label spelling and scrape activity:
curl -sG --data-urlencode "match[]=http_requests_total" "$PROM/api/v1/series" | jq '.data | length'

# 3. Sanity-check the magnitude — open Grafana Explore, paste the expr,
#    confirm the values look right against a known ground truth (k6 run, log count, etc.)
```

### 2. Common patterns to copy

**Per-status request rate** (aggregate AFTER rate):

```promql
sum(rate(http_requests_total{job="api"}[5m])) by (status_code)
```

**p95 latency** (must keep `le` in the inner aggregation):

```promql
histogram_quantile(0.95,
  sum(rate(http_request_duration_seconds_bucket[5m])) by (le, service))
```
````
END THIRD-PARTY FILE 602a610f94911422

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