Skills vs MCP vs Projects: Understanding the Differences in Your AI Stack

Programming· 6 min read

Skills vs MCP vs Projects: Understanding the Differences in Your AI Stack

The Problem: Too Many Ways to Do the Same Thing

You've been working with Claude for three months. You've tried Projects, you've heard about MCP, and now Skills appear. The obvious question: which one should I use?

The typical answer is "it depends," but that doesn't help you. What you need is a clear mental framework to know exactly when each tool is right.

I went through this myself. I built an entire system using Projects when I should have used MCP. Then I tried to use MCP for something that was clearly a Skills case. I learned through pain, so I'll save you that time.

Projects: Your Persistent Context

Projects is for long-term memory.

When you create a Project in Claude, you're saying: "This context matters. I want you to remember it between conversations."

Think of Projects as your private knowledge base. Everything you add to a Project stays there:

  • Technical documentation of your product
  • Code style guides and conventions
  • API specifications you built
  • Architectural decision histories
  • Examples of how you want Claude to behave with you

Real case: I have a Project for each major client. Inside is all the documentation of their stack, their code preferences, their recent change histories. When I return to their project a week later, Claude already knows exactly how they think, how they structure code, what problems they've had.

Without Projects, I'd have to re-explain everything each time. With Projects, it's like I never left.

``` Project: ClientX ├── Technical documentation ├── Code conventions ├── Change history ├── Architectural decisions └── Implementation examples ```

When to use Projects:

  • You work regularly on the same project
  • You need consistency between sessions
  • The context is specific to you or your team
  • You're building something that evolves over time

MCP: Your External Connections

MCP is for integrating external tools and services.

MCP stands for Model Context Protocol. It's the bridge between Claude and the rest of the world. When you configure an MCP, you're giving Claude access to:

  • Databases (Supabase, PostgreSQL)
  • External APIs (GitHub, Twitter, Slack)
  • File systems
  • Specialized tools (web scrapers, data analyzers)

The critical difference: MCP is for real-time connections. When Claude uses an MCP, he's querying live data, not stored context.

Real case: I have an MCP configured that connects Claude directly to my GitHub repository. When I ask him to review code, I don't pass files—he accesses the repository directly. When he asks "what's the latest version of this file?", he gets the answer in real time.

Another example: an MCP that connects to Supabase. Claude can query data, create records, update information. All without me doing anything manual.

``` Claude ↓ MCP Server (GitHub) ↓ Your repository in real-time

Claude ↓ MCP Server (Supabase) ↓ Your database in real-time ```

When to use MCP:

  • You need constantly updated data
  • You want Claude to interact with external systems
  • You're building automation that requires live connections
  • Multiple users need access to the same data

Skills: Your Reusable Procedures

Skills are for encapsulating procedures you repeat constantly.

This is the part many developers don't understand well. Skills aren't context (that's Projects). Skills aren't connections (that's MCP). Skills are procedural instructions Claude can use as building blocks.

A Skill is basically: "Here's a specific task I do often. When you need it, do it exactly like this."

Examples of Skills:

  • "When you review code, use this specific checklist"
  • "When you write documentation, follow this format"
  • "When you analyze a performance problem, execute these steps in this order"
  • "When you create a React component, always include these tests"

Real case: I have a Skill for "Structured Code Review." It defines exactly how I want Claude to review code:

1. First, analyze the overall architecture 2. Then, look for security issues 3. Next, review performance 4. Finally, check readability and maintainability

Every time I use this Skill, Claude follows the same process. It's consistent, it's thorough, and I don't have to repeat instructions.

Another Skill: "Product Idea Validation." When I have a new idea, I run this Skill that asks me specific questions, challenges my assumptions, and helps me validate whether it's worth building.

When to use Skills:

  • You repeat the same procedure constantly
  • You want consistency in how Claude approaches certain tasks
  • The procedure is complex and has multiple steps
  • You want others (your team, other users) to execute the same process

The Mental Framework: When to Use Each One

Here's the framework I use to decide:

Is it context you need to remember between conversations? → Use Projects

Is it an external connection to a live system? → Use MCP

Is it a procedure you repeat constantly? → Use Skills

The Right Architecture

In a real project, you typically need all three:

``` Project: My Startup ├── Technical documentation ├── Architecture decisions └── Change history

MCP Connections: ├── GitHub (real-time code access) ├── Supabase (real-time data access) └── Slack (for notifications)

Skills: ├── Structured Code Review ├── Idea Validation ├── Performance Debugging └── Decision Documentation ```

They work together. The Project gives you context. MCPs give you live connections. Skills give you consistent procedures.

The Most Common Mistake

Most developers try to do everything with Projects. They put all the context there and hope it works.

The problem: Projects don't scale well. If you need real-time data, Projects won't give it to you. If you need to execute the same procedure 50 times, Projects isn't efficient.

I made this mistake myself. I had a Project with 500 lines of documentation about how to review code. It should have been a Skill. Now it's a Skill, and Claude executes it perfectly every time.

What Matters Now

You don't need to understand all the complexities of Projects, MCP, and Skills right now. What you need is:

1. Understand the conceptual difference: persistent context vs. external connections vs. procedures 2. Start small: create a Project for your current project, a Skill for your most repeated task 3. Iterate: as you build, you'll see where you need MCP

Most developers I know are using Projects correctly but missing opportunities with Skills. If you repeat something more than three times, it probably should be a Skill.

Next Steps

Today:

1. Create a Project for your current project 2. Identify a task you repeat constantly 3. Convert that task into a Skill 4. Watch how your workflow improves

The difference is small in theory. In practice, it's huge.