How do I install the Lowercase skill?

Run npx skillmds@latest add thedaviddias/lowercase in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Lowercase safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Lowercase?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Lowercase free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Lowercase?

thedaviddias (@thedaviddias) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Lowercase by thedaviddias — Agent Skill

Name: Lowercase
Author: thedaviddias

File contents

Use lowercase URLs

Mixed-case URLs can create duplicate content—search engines may index both /Product and /product as separate pages, splitting link equity and diluting rankings.

Quick Reference

URLs should be entirely lowercase to prevent duplicate content issues
Most web servers treat /Page and /page as different URLs, creating duplicates
Redirect uppercase and mixed-case URLs to their lowercase equivalents with 301
Apply lowercasing in your server config or framework router, not ad hoc

Check

Scan the site's internal links and server-side routes for URLs containing uppercase letters. Check HTTP response codes for uppercase variants of key URLs to confirm whether they redirect (301) to lowercase.

Fix

Configure your server or framework to normalize all incoming URLs to lowercase before routing. Add 301 redirects from any existing uppercase URLs to their lowercase equivalents. Update internal links and sitemaps to use only lowercase URLs.

Explain

URL case matters for SEO because case-sensitive servers treat /Page and /page as different resources, creating duplicate content. Even on case-insensitive servers, inconsistency confuses crawlers and splits PageRank across URL variants.

Code Review

Scan the site's route definitions, server configuration, and internal links for uppercase letters in URL paths. Test key URLs in uppercase and mixed case — verify they return 301 to the lowercase version, not 200. Check the sitemap for any uppercase entries. Verify framework router is configured to normalize URL case.

For full implementation details, code examples, and framework-specific guidance, see references/rule.md.

Rule page: https://frontendchecklist.io/en/rules/seo/lowercase

---name: lowercasedescription: Use when auditing URL structure or configuring a new site's routing. Applies to any server or framework that allows case-insensitive file systems (Linux servers are case-sensitive by default).---# Use lowercase URLsMixed-case URLs can create duplicate content—search engines may index both /Product and /product as separate pages, splitting link equity and diluting rankings.## Quick Reference- URLs should be entirely lowercase to prevent duplicate content issues- Most web servers treat /Page and /page as different URLs, creating duplicates- Redirect uppercase and mixed-case URLs to their lowercase equivalents with 301- Apply lowercasing in your server config or framework router, not ad hoc## CheckScan the site's internal links and server-side routes for URLs containing uppercase letters. Check HTTP response codes for uppercase variants of key URLs to confirm whether they redirect (301) to lowercase.## FixConfigure your server or framework to normalize all incoming URLs to lowercase before routing. Add 301 redirects from any existing uppercase URLs to their lowercase equivalents. Update internal links and sitemaps to use only lowercase URLs.## ExplainURL case matters for SEO because case-sensitive servers treat /Page and /page as different resources, creating duplicate content. Even on case-insensitive servers, inconsistency confuses crawlers and splits PageRank across URL variants.## Code ReviewScan the site's route definitions, server configuration, and internal links for uppercase letters in URL paths. Test key URLs in uppercase and mixed case — verify they return 301 to the lowercase version, not 200. Check the sitemap for any uppercase <loc> entries. Verify framework router is configured to normalize URL case.---For full implementation details, code examples, and framework-specific guidance,see `references/rule.md`.Rule page: https://frontendchecklist.io/en/rules/seo/lowercase

Frequently asked questions

Lowercase