Anthropic launched Skills quietly. Most marketers haven't noticed. Here's what they are, when to use them, and four free marketing Skills to install in the next ten minutes.
Anthropic shipped Skills without a lot of fanfare. If you missed it, you're not alone, most marketers I talk to haven't heard the term yet. Which is the moment to learn it, before every prompt-library vendor stuffs the marketplace with low-quality bundles and the signal-to-noise drops.
Skills are the third primitive in the Claude ecosystem. Projects pin context. System prompts shape the model's behaviour. Skills are the bit that's been missing, packaged, reusable, retrievable instructions Claude can invoke automatically when a task matches.
Installing 15 overlapping Skills wastes Claude's retrieval. When two Skills both look relevant to a query, Claude has to choose, and the choice is probabilistic. More Skills doesn't mean better outputs. It means Claude's retrieval gets noisier and your results get less consistent.
Three really good Skills beat fifteen mediocre ones. Audit your installed list quarterly.
A Skill is a folder. Inside it: a SKILL.md file with YAML frontmatter that tells Claude what the Skill does, when to invoke it, and what tools it can use. Plus any reference files the Skill needs (templates, examples, checklists).
The frontmatter looks like this:
name: voice-tone-extractor
description: Derive a reusable brand voice and tone guide from existing writing samples...
When Claude detects a task that matches the Skill's description, it pulls the Skill in automatically. You don't have to tell Claude to use it, though you can ("use the voice-tone-extractor Skill on these blog posts"). The match is based on the description, which is why the description field is the most important part of a Skill.
This is the bit nobody explains well, so here's the operator version.
Use a system prompt when you're shaping Claude's behaviour for a single conversation. "Be a senior strategist. Refuse to declare a trend from one data point." Dies when the conversation ends.
Use a Claude Project when you want persistent context, your brand voice, your KPIs, your tools, your non-goals. Every conversation inside the Project inherits the context. Best for team workflows where everyone needs the same baseline.
Use a Skill when you want a reusable, model-invocable instruction bundle. Skills are packaged. You can share them. You can install them across multiple Projects. And (the key feature) Claude can choose to invoke them automatically based on the task.
Most marketers don't need all three. The combination I'd suggest: a Claude Project with your brand context pinned, plus 3-5 well-chosen Skills that cover the tasks you do weekly. That's the lean stack.
SKILL.md and the Skill is available immediately.That's it. For Claude Code, the folder goes into .claude/skills/ in your project root (project-scoped) or ~/.claude/skills/ (personal, all projects).
These are the four free prompts from the Marketing Prompt Hub, repackaged as installable Skills. CC BY 4.0, use them however you want, commercial or personal, with or without attribution. Download the whole bundle (12kb).
Paste 2-3 on-voice pieces of your brand writing, get back a reusable voice guide. Three voice attributes with opposites, sentence rhythm patterns, vocabulary lists. The output is itself a system prompt you paste into a Project.
Paste competitor URLs/content, get a comparison matrix + executive summary + three positioning hypotheses with kill criteria.
Paste a target query and the top 10 SERP results, get a brief that beats them on something specific (not on length).
Paste a CSV + your period + your goals, get an honest readout that refuses to declare trends from fewer than two data points.
Audit your last two weeks of Claude conversations. Look for tasks you ran more than once. Those are Skill candidates. Tasks you ran once and never again, those don't need to be Skills. Just write the prompt fresh.
Three really good Skills, each one earning its retrieval slot, beats fifteen mediocre ones every time. The marketplace is going to fill up fast. Be picky now.
Bundle is 12kb. Drag into Claude Desktop. No email, no signup. Same prompts as the four free /free/ pages, packaged for retrieval. CC BY 4.0.
Get the Skills →