Claude Skills vs Projects vs Custom GPTs vs Prompts: Which to Use When

Use a prompt for a one-off request, a Project for background knowledge about a body of work, and a skill for a method you repeat. Custom GPTs bundle instructions and knowledge into one assistant inside ChatGPT. For a team, the deciding question is which of these the company owns and can keep consistent.

What is the difference between Skills, Projects, prompts and custom GPTs?

They hold different things. A prompt holds one instruction for one conversation. Projects hold background knowledge for a body of work. Each skill holds a method for a task, used wherever that task comes up. Finally, a custom GPT is a configured assistant in ChatGPT combining instructions, knowledge and capabilities in one place.

Anthropic's own explainer draws the core line simply. Projects provide persistent background knowledge, while skills teach Claude how to do things. OpenAI describes GPTs as "custom versions of ChatGPT that combine instructions, extra knowledge, and any combination of skills".

When should you use a prompt?

Use a prompt for anything you do once or rarely: a quick question, a one-off draft, an experiment. Prompts are fast and flexible. Their weakness is that they vanish. If you find yourself retyping the same prompt, or keeping a document of favourite prompts, it is time to turn it into something that persists.

According to Anthropic's comparison, prompts "don't persist across conversations". That is fine for a single job. It becomes a problem across a team, because each person's prompts live in their own head or notes, and the quality varies with who wrote them.

A useful rule: the third time you paste the same instructions, stop and make them reusable.

When should you use a Project?

Use a Project when Claude needs background knowledge for a body of work: a client account, a product launch, a research topic. Upload the relevant documents and set instructions, and every conversation in that Project starts with that context. Projects suit knowledge that is specific to one area and changes as the work goes on.

Projects work well for focused, bounded work. For instance, a Project for one client might hold their brief, past reports and brand guidelines, so every draft starts informed.

The limits show up at scale. A Project's knowledge stays inside that Project. If several Projects need the same company facts, someone copies them into each, and the copies drift apart. That is where shared knowledge, maintained once, starts to matter. The guide to Claude Projects for teams covers good practice.

When should you use a skill?

Use a skill for a method you repeat: how your company writes a proposal, formats a report, checks an article or analyses a spreadsheet. A skill holds the steps, checks and examples, and Claude loads it whenever a request matches. Skills travel across conversations and Projects, so the method is the same everywhere.

The signal is repetition of instructions. Anthropic puts it directly: "If you find yourself copying the same instructions across multiple Projects, that's a signal to create a skill instead."

Skills also scale well. Each one has a short name and description that Claude reads first, and loads the full instructions only when relevant. According to Anthropic's help documentation, the description is limited to 200 characters and should say what the skill does and when to use it. A team can therefore install many skills without cluttering every conversation.

Where do custom GPTs fit?

Custom GPTs are ChatGPT's way of packaging instructions and knowledge into a single, shareable assistant. They suit a well-defined purpose, such as an assistant for drafting job ads or answering policy questions. Their limit is that each GPT is a separate assistant, so a method lives inside one GPT rather than travelling across all your work.

The comparison is not like for like. A custom GPT is closest to a Project and a skill combined: knowledge and method bundled together in one place. That is convenient for a single job. However, it means the method is tied to that assistant and that vendor.

Portability is the other difference. In December 2025 Anthropic published Agent Skills as an open standard, with the specification at agentskills.io, so other tools can adopt the same format. A skill written in the standard format is a file your business owns and can move.

Which suits a team best?

For a team, the strongest setup combines shared knowledge with shared skills: one maintained set of company facts that every AI reads, and skills for the jobs everyone does. Projects then hold work-specific context, and prompts handle the one-offs. The key is that the business, not individuals, owns the knowledge and methods.

The risk with any of these tools is fragmentation. According to Microsoft and LinkedIn's 2024 Work Trend Index, 78% of AI users bring their own tools to work. If each person builds private Projects, prompts and GPTs, the business ends up with many slightly different versions of how it works.

A practical division of labour:

• Company facts: one shared, maintained source every AI reads.
• Methods: skills for the repeatable jobs, owned and versioned.
• Work context: Projects for specific clients or initiatives.
• One-offs: prompts.

That structure is what a Company OS formalises: a company brain for facts, skills for methods, agents that use both. Skein builds it inside growing teams; the skill library shows the kinds of skills involved. It suits a team where several people repeat the same work with AI. A solo user may need nothing more than a couple of Projects and one or two personal skills.

Frequently asked questions

What is the difference between Claude Projects and Skills?

Projects give Claude background knowledge for a specific body of work, such as a client or a campaign. Skills teach Claude how to do a task, such as writing a report in your format, and work across all conversations and Projects. Anthropic suggests creating a skill when the same instructions are copied into several Projects.

Are Claude Skills better than custom GPTs?

They solve slightly different problems. A custom GPT bundles instructions and knowledge into one shareable assistant inside ChatGPT. A skill is a portable method that loads wherever a matching task appears, and follows an open standard. For repeatable methods used across many tasks, skills are usually the more flexible choice.

When should I use a Claude Project?

Use a Project when Claude needs ongoing background knowledge for one area of work, such as a client's brief and history or a product launch. Upload the relevant documents and instructions so every conversation in the Project starts informed. Shared company-wide facts are better kept in one maintained source.

Can Claude Skills replace prompts?

Skills replace prompts you repeat, not every prompt. If you keep pasting the same instructions, turning them into a skill makes them persistent and consistent across the team. One-off requests, quick questions and experiments are still best handled with a simple prompt.

Do skills work with Projects?

Yes. Skills travel across conversations and Projects, so a skill for writing reports works inside any Project that needs a report. The Project supplies the specific context, such as the client's details, while the skill supplies the method for doing the job.

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