What is a Claude Code skill?

If you have used Claude Code (Anthropic’s agentic coding environment), you may have seen slash commands like /seo audit or documentation referring to a skill. A Claude Code skill is a packaged bundle of instructions, scripts, and conventions that Claude loads so it knows how to perform a specialized workflow consistently.

This guide explains skills in plain language—no assumption that you already run a terminal—and points to how Claude SEO fits in and how ClaudeSkillSEO.com offers a web UI on top of that skill.

What a skill is (and is not)

A skill is not a separate AI model. It is context and procedure shipped as files (often under ~/.claude/skills/ or a project skills directory) that Claude reads when you invoke a matching command.

Think of it as:

• A playbook for a domain (SEO, security review, release notes)
• Slash commands that expand into detailed prompts
• Sometimes helper scripts or folder layouts the model must respect

It is not:

• A guaranteed plugin API with fixed binary behavior
• A replacement for your site’s own code or Google Search Console
• Automatically “official” Anthropic product—many skills are community or vendor maintained

Slash commands and prompts

When you type /seo audit https://example.com in Claude Code, the seo skill typically:

1. Parses the command and target URL
2. Applies rules from its SKILL.md or equivalent manifest
3. May spawn sub-tasks (other agents) for crawl, schema, content, performance, GEO
4. Writes reports to agreed paths (for example workspace-files/<run>/)

Skills can enforce one-turn behavior in headless mode so a background job does not exit before sub-agents finish—a common requirement for automated hosts like ClaudeSkillSEO.

Skills vs MCP vs custom instructions

Approach	Role
Skill	Domain workflow + slash commands + file conventions
MCP server	Live tools (APIs, databases, browsers) Claude calls during a session
Project CLAUDE.md	Repo-specific rules for one codebase

SEO audits often combine a skill (methodology) with tools (fetch URL, parse HTML, run Lighthouse). The Claude SEO skill encodes SEO methodology; the host environment still provides Claude and tooling.

How Claude SEO relates

Claude SEO is a well-known open-source skill by Agrici Daniel (MIT license) focused on technical SEO, content, schema, performance, and GEO-style checks. It is one skill among many you could install in Claude Code.

Read the dedicated overview: What is the Claude SEO skill by Agrici Daniel?.

ClaudeSkillSEO.com uses that skill in its hosted audit engine; it did not author the upstream project.

When to use skills in the terminal vs a web UI

Developers and SEO leads who already live in Claude Code often prefer:

• Local skills they can patch
• Git-tracked workspace-files on their machine
• Interactive debugging in a PTY

Teams who want shared history, credit billing, and no local setup often prefer a web interface. Compare both paths in Claude SEO skill CLI vs ClaudeSkillSEO web interface.

FAQ

Do I need to pay Anthropic twice—Claude and a skill host?

You need access to Claude (API or subscription, depending on your setup). A host like ClaudeSkillSEO may bill AI credits for successful runs on top of that. Local Claude Code usage follows your Anthropic plan plus your own infrastructure.

Can I write my own skill?

Yes. Anthropic documents skill structure for Claude Code. Claude SEO is an example of a community skill you can study, fork under MIT terms, or extend.

Where does the skill run on ClaudeSkillSEO?

On the platform’s servers, headlessly, with outputs stored per account run. See the main ClaudeSkillSEO overview.