A prompt is a single instruction you run once. A skill is a reusable file that teaches your AI how to do one kind of task every time. An agent is an AI set up to carry out multi-step work on its own, often using skills and tools to get there. Prompt = one ask. Skill = standing know-how. Agent = an autonomous doer.
These three power most of what people do with AI today, and mixing them up leads to buying the wrong thing. Here's the clean distinction, when to use each, and how they fit together.
Quick definitions
- Prompt - text you type to get a result right now. Powerful, but you supply it fresh each time. A prompt pack is a curated set of these for a topic.
- Skill - a reusable instruction file your AI loads when a task matches, so it performs like a specialist without re-prompting.
- Agent - an AI configured to pursue a goal across multiple steps: it plans, acts, checks, and iterates, often calling skills and external tools along the way.
One thing worth knowing if you're comparing store listings: a skill and an agent are usually the same underlying file - a .skill package with a SKILL.md document inside. What differs is how that document is written. A skill's document describes a role and a menu of things it can do, so you stay in charge of the conversation. An agent's document describes a short, fixed intake - a handful of questions it asks before it will produce anything - and one named output packet, the same shape every time you run it.
A one-off need, like writing a single SEO article, is exactly what a prompt pack is built for: no setup, just paste and go each time you need a new piece.
View AI SEO Writer →Side-by-side
| Prompt | Skill | Agent | |
|---|---|---|---|
| What it is | A single instruction | Standing know-how (a file) | An autonomous doer |
| Lasts | One message | Across every chat | Across a whole task |
| You do | Write it each time | Install once | Set a goal, let it run |
| Best for | Quick one-offs | Repeatable tasks | Multi-step workflows |
| Effort | Lowest | Low (one-time setup) | Higher (more capable) |
What agents don't do (and why that's fine)
Because "agent" gets used loosely across the industry, it's worth being precise about what an agent file on this store actually is: a fixed intake followed by one compiled deliverable, run in a single chat session with you answering the questions. That's genuinely useful - but it isn't the same as an autonomous system running unattended, and the honest limits are worth stating plainly:
- An agent file doesn't browse the internet on its own. If Claude has web access in your setup, it has it either way - the file doesn't add it.
- An agent file doesn't connect to your CRM, bank, repository or ad account. No credentials, no connection layer. It works with what you type or paste into the conversation.
- An agent file doesn't run while you sleep. There's no background process - one session, in a chat, with you in it answering the intake questions.
- An agent isn't smarter than a skill - it's more disciplined. It removes your choices on purpose so the deliverable comes out the same shape every time, whether you're the one driving it or a colleague on their first week is.
Asks for your product idea, dimensions, landed cost, competitor listings, target price and ad budget, then returns one FBA Launch Packet: a go or no-go scorecard, a margin waterfall down to profit per unit, full listing copy, and a 14-day advertising ramp plan.
View Rhea →That structure is also how you can spot an agent listing before you buy: it names its deliverable ("FBA Launch Packet," "Client Acquisition Packet") and tells you upfront what it's going to ask for. A skill listing describes a role instead and leaves the shape of each answer open.
When to use each
Use a prompt (or prompt pack) when…
You need a result now and the task varies each time - brainstorming, a one-off email, rewriting a paragraph. A prompt pack saves you from reinventing good prompts for a recurring topic.
Worth understanding why a prompt's usefulness has a shelf life within a chat. A prompt lives inside the conversation - it's a message, and the moment you send it, it starts competing with everything that comes after. Ask a few follow-ups, paste a document, request three variations: by message fifteen or twenty, your original brief is buried under newer, narrower material, and the answers drift back toward generic. The model hasn't forgotten your instructions; they're just competing for attention with something more recent and more specific. A skill sidesteps this because it isn't read from the history at all - it's loaded fresh from a file whenever a request matches, so it's exactly as loud on message forty as it was on message one. More on the mechanism in why long chats get dumber and context windows explained.
Use a skill when…
You do the same kind of task repeatedly and want consistent output without re-explaining - code review to your standards, weekly reports in your format, on-brand copy. Four signals are worth checking if you're unsure: the task repeats (anything you'll do more than about ten times), consistency matters (three people shouldn't produce three different formats for the same document), the role has a method and not just an output (an order of steps, not just an instruction), or you're retyping the same clarifications every session. Two or more of those, and you've outgrown prompting for that job. Browse skill files.
Instead of re-explaining your SEO standards every time, install Serge once and every future chat automatically gets keyword clusters, technical audits, and content briefs done his way.
View Serge - SEO Specialist AI Skill →Use an agent when…
The job has multiple steps you'd rather not babysit - research then draft then format, or a recurring operational process. Browse AI agents.
Rather than running the prompt and skill yourself step by step, Alistair researches keyword intent, builds the structure, and writes the complete SEO-optimized article end-to-end in one session.
View Alistair - AI SEO Content Agent →How they fit together
They're layers, not rivals. A prompt is the smallest unit. A skill packages know-how so you stop re-typing prompts. An agent orchestrates the work, reaching for skills (and external tools via MCP) to complete a goal. In practice a capable agent uses skills; a skill replaces a prompt you'd otherwise paste every time.
If you already have a prompt that works well, turning it into a skill is mostly mechanical: separate the sentences that say when this applies from the sentences that say how the work gets done. The first becomes the skill's description - the trigger the model matches against. The second becomes the body. The specific input stays out of the file and in your message, every time. Walkthrough here: prompt pack vs skill file.
Which should you buy?
- Just exploring or on a budget → start with a prompt pack.
- Same task, over and over → get a skill; it pays back fastest.
- A whole workflow to automate → get an agent.
How to tell which one a listing actually is
Two questions cut through most of the ambiguity on a product page. Is there a named deliverable - "Launch Packet," "Client Acquisition Packet" - or a described role? A named packet means agent; a described role means skill. And does the description mention an intake list, specific inputs the file will ask for before it produces anything? That gating behavior is an agent trait; skills don't usually work that way.
Not sure? Try a free generator or a free skill first - both show the "set it once, reuse forever" payoff at zero cost.
Frequently asked questions
Is a skill just a saved prompt?
No. A prompt runs once; a skill is a reusable file your AI loads automatically when a task matches, so it applies the same expertise across every conversation without you pasting anything.
Do I need an agent, or is a skill enough?
If your task is a single kind of output, a skill is usually enough. If it's a multi-step process you'd rather not run by hand, an agent is the better fit - and it can use skills internally.
What's a prompt pack?
A curated collection of ready-to-use prompts for a topic or role. You copy and run them manually, task by task - great when the work varies each time.
Can I use all three together?
Yes, and many people do: prompts for quick asks, skills for repeatable tasks, and agents for end-to-end workflows that lean on those skills.
Are Claude agents actually autonomous, running on their own?
Not the ones sold as skill files, including ours. An agent runs one session, with you answering its intake questions; it doesn't browse the web, connect to your other systems, or work unattended unless the underlying assistant already has that access independent of the file.
Why did my prompt stop working halfway through a long chat?
It didn't stop working - it got buried. Prompts live in the conversation history, and as you add follow-ups, pasted documents and new requests, the original brief competes with material that's more recent and more specific. A skill avoids this because it's loaded from a file each time, not read out of the scrolling history.
In summary:
For a one-off SEO article, grab the AI SEO Writer prompt pack; for consistent SEO work in every chat, install Serge - SEO Specialist AI Skill; and if you want the whole article researched and written for you end-to-end, get Alistair - AI SEO Content Agent. All work in Claude, ChatGPT and any AI chat with no coding and a 30-day money-back guarantee.
Pick your layer
Match the tool to the job: prompts for one-offs, skills for repeatable work, agents for full workflows. New to the idea? Start with what Claude Skills are.