promql

Write and optimize PromQL queries for Prometheus and Grafana Cloud Metrics.

Updated Mar 18, 2026
One-click install
npx skills add https://github.com/Canepro/codex-skills --skill promql-canepro
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: promql
Source: https://github.com/Canepro/codex-skills/tree/main/skills/promql
Command: npx skills add https://github.com/Canepro/codex-skills --skill promql-canepro

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

PromQL expression authoring and optimization for time-series data in Prometheus and Grafana Cloud Metrics, improving accuracy and performance of dashboards and alerts.

Core Features & Use Cases

  • Query construction: build rate, histogram_quantile, and aggregation queries that return correct results across multi-label environments.
  • Validation and optimization: verify query correctness, reduce cardinality, and pre-compute expensive expressions with recording rules.
  • Use Case: For a service with many instances, create a query to monitor per-service error rate and latency percentiles, then alert when thresholds are breached.

Quick Start

Ask me to generate a rate query for http_requests_total over the last 5 minutes.

Frequently Asked Questions about promql

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I write a PromQL query to calculate the error rate for a service with multiple labels?▼

To calculate a per-service error rate in PromQL, you aggregate error metrics by labels and divide by total requests. This skill constructs precise rate queries that return correct results across multi-label environments.

What is the best way to compute latency percentiles using histogram_quantile in Prometheus?▼

Computing latency percentiles with histogram_quantile requires correctly grouping bucket boundaries and labels. This skill generates valid histogram_quantile queries for accurate latency monitoring in Grafana Cloud Metrics and Prometheus.

How can I reduce high cardinality in Prometheus time-series data?▼

Reduce high cardinality by pre-computing expensive PromQL expressions with recording rules. This skill validates query correctness and optimizes metrics to lower cardinality across services.

Can I build SLO alerts and dashboards with PromQL for Grafana Cloud Metrics?▼

Yes, you can build SLO alerts and dashboards using PromQL for Grafana Cloud Metrics. This skill supports SLO query construction and threshold-based alerting for time-series data.

Why does my Prometheus rate calculation return empty or incorrect results?▼

Prometheus rate calculations fail when time windows or label matchers are misconfigured. This skill writes and validates rate queries over specified intervals to ensure accurate time-series results.