Claude Code Skills are filesystem-based instruction packages that give Claude domain-specific expertise: workflows, scripts, and reusable resources Claude loads on demand whenever a task calls for them. They turn Claude Code from a general assistant into a specialist that already knows how your team builds things. The piece they leave open, on purpose, is the deploy step. A Skill writes the project, but it does not ship the project. That gap is what a Skill plus Totalum closes.
This guide explains what Claude Code Skills are, what shipped around them in May 2026, and how a single Skill paired with the Totalum MCP server can scaffold a real Next.js app, push it through auth and database setup, and end with a deployed URL on a custom domain. It also compares the three places a Skill commonly runs in 2026 (local filesystem, Vercel Sandbox, Totalum) so you can pick the right home for yours.
Quick Answer
- A Claude Code Skill is a folder containing a SKILL.md file plus optional helper scripts; Claude discovers and runs it automatically when the task matches.
- Skills give Claude Code repeatable expertise. They do not, by themselves, deploy a project to production.
- Pairing a Skill with the Totalum MCP server adds the missing runtime: a real Next.js app, owned code, database, auth, payments, file storage, and a custom domain.
- Search volume for "claude code skills" climbed from roughly 10 queries per month in September 2025 to 27,100 in March 2026, one of the fastest-growing terms in the AI coding category.
- For software agencies and SaaS teams, a Skill plus Totalum turns an internal workflow into a shippable client deliverable in a single Claude session.
What are Claude Code Skills (and what they are not)
A Skill is, in plain terms, a folder. Inside it lives a SKILL.md file (the instruction set Claude reads) plus optional scripts and assets. Claude Code discovers Skills automatically from the filesystem. You do not register them through an API and you do not enable them per request. When the model sees a task that matches a Skill's stated purpose, it loads the SKILL.md, follows the steps, and uses whatever scripts the folder contains.
In Anthropic's Agent Skills documentation, Skills are described as "reusable, filesystem-based resources that provide Claude with domain-specific expertise." That sentence matters because it draws a clean boundary. Skills carry knowledge and conventions. They do not carry runtime, hosting, or a database. A Skill that says "scaffold a Next.js app with auth and a leads table" will produce code on your disk. It will not stand up a domain. That is by design. Skills are the package, not the destination.
Three small distinctions help when you read the rest of this guide:
- A Skill is filesystem-based, not API-based. Claude Code looks inside
~/.claude/skills/or a project-local folder and uses whatever is there. - A Skill is different from a tool. Tools (and MCP servers) give Claude new actions it can take in the world; Skills give Claude new things it knows how to do well.
- A Skill is different from an agent. Agents string actions together over time; a Skill is closer to a recipe an agent can pick up.
The two pair naturally. A Skill tells Claude "here is how we build a client onboarding portal in our shop." An MCP server like Totalum gives Claude the ability to actually create the project, write the database schema, and deploy it.
What changed in May 2026
Three vendor events in the last week made Skills more useful at the same time:
- Anthropic's Skills feature continued its accelerating adoption. Search volume for the parent term "claude skills" reached 90,500 monthly searches in March 2026, up from roughly 10 a year earlier. The "claude code skills" subset sits at 8,100 monthly searches and is climbing 22% month over month at the time of writing.
- Vercel shipped "Run Claude Managed Agents with Vercel Sandbox" on May 18, 2026. Managed Agents, the hosted side of Claude's agent stack, can now run inside an isolated Vercel sandbox, which gives the Skill a place to execute outside your local machine.
- Anthropic acquired Stainless on May 18, 2026. Stainless is best known as an SDK generator; the move signals deeper investment in developer-tooling packaging, which is the broader trend Skills sit inside.
Put together, the picture is straightforward. More people are searching for Skills, more places exist to run them, and Anthropic is investing more in the surrounding developer surface. The thing that has not moved is the production gap. A Skill that scaffolds an app still hands you a folder; it does not hand you a URL.
Where Skills end and Totalum begins
A modern Claude Code session that builds a real app touches three jobs:
- Thinking: model plus agentic harness plus Skill (this is Claude Code itself, augmented by Skills).
- Shipping: turning code into a deployed, hosted application with auth, a database, payments, file storage, and a domain.
- Orchestration: scaffolding new projects, editing existing ones, querying production data, and rolling forward when something breaks.
Skills are the cleanest way to standardise job 1. Totalum, exposed as an MCP server, is built to handle jobs 2 and 3. The MCP server gives Claude actions like "create a Totalum project," "deploy this version," "add this table," "set this environment variable," and "open this preview URL." Those actions are how the Skill's plan turns into a running app.
The result of the pairing is that one Claude session can:
- Read a SKILL.md that describes "our standard client onboarding portal."
- Generate the Next.js code and the database schema.
- Call the Totalum MCP server to create the project, push the code, run the build, and return a preview URL.
- Wire a custom domain when the human confirms.
You do not stop using Claude Code. You stop stopping at the deploy step.
Skills plus filesystem vs Skills plus Vercel Sandbox vs Skills plus Totalum
The three common homes for a Claude Code Skill differ in what they hand back when the Skill finishes running. The table below covers the practical points.
| Capability | Skills + local filesystem | Skills + Vercel Sandbox (May 18, 2026) | Skills + Totalum (via MCP) |
|---|---|---|---|
| Where the Skill executes | Your machine | Hosted Vercel sandbox | Hosted Totalum runtime |
| What you get when it finishes | Files in a folder | Files in a sandbox plus optional artifacts | A deployed Next.js app with a URL |
| Built-in database | No | No | Yes (Totalum database) |
| Built-in auth | No (DIY) | No (DIY) | Yes (out of the box) |
| Built-in payments | No (DIY) | No (DIY) | Stripe integration ready |
| Custom domain at the end | Manual | Manual | One step from Claude |
| Multi-project, parallel use | Limited (one disk) | Strong (isolated sandboxes) | Strong (each project is owned and isolated) |
| Owned code | Yes | Yes | Yes (real Next.js, exportable) |
| Best fit | Solo dev, local experiments | Background runs, ephemeral compute | Production apps and client deliverables |
The three options are not exclusive. The most common 2026 pattern is to keep the Skill itself in your repo (so the team agrees on conventions), let Claude Code run the Skill, and end the chain with a Totalum MCP call so the output is a deployed app rather than a folder.
Tutorial: a Skill that scaffolds and ships a Totalum app
Below is a minimal Skill that builds a client portal end to end. Drop it into ~/.claude/skills/client-portal/SKILL.md (or your project's .claude/skills/ folder) and Claude Code will pick it up on the next session.
---
name: client-portal
description: Scaffold and ship a production client portal with auth, a leads table, and a custom domain
---
# Client Portal Skill
When the user asks for a "client portal" or "lead intake app", do the following.
## Step 1: Scope check
Ask the user for client name, primary brand colour, and whether they need email notifications.
## Step 2: Create the project on Totalum
Use the Totalum MCP server (createProject) to create a new project.
Project name: -portal.
## Step 3: Database schema
Add a leads table with: full_name (string), email (string), company (string),
notes (long_string), status (options: new, contacted, qualified).
Add a users table for portal logins per the auth docs.
## Step 4: UI
Generate a clean Next.js dashboard with a leads list, a lead detail view,
and a public intake form route.
## Step 5: Auth and payments
Wire Better Auth per Totalum's auth docs. Skip payments unless asked.
## Step 6: Deploy
Call the deploy action and return the preview URL.
## Step 7: Domain
If the user confirms, attach the requested domain via the Totalum MCP
and return the live URL.Pair the Skill with the Totalum MCP server in your .mcp.json (or Claude Code settings):
{
"mcpServers": {
"totalum": {
"type": "http",
"url": "https://mcp.totalum.app/v1/mcp",
"headers": {
"Authorization": "Bearer YOUR_TOTALUM_API_KEY"
}
}
}
}In a new Claude Code session, type "build a client portal for Acme, brand colour navy, no emails." The Skill takes over. Claude reads the SKILL.md, asks any clarifying questions, runs the steps, and returns a deployed URL. The folder on your disk is incidental; the deliverable is a working app on a Totalum subdomain (and your custom domain once the human confirms).
Two notes worth remembering:
- A Skill is plain Markdown. Keep it short, opinionated, and free of clever syntax. Claude executes the spirit of the file, not a parser-bound DSL.
- Steps that touch the world (create project, deploy, attach domain) should be MCP calls, not shell scripts. MCP gives the human a clean approval surface and a consistent audit trail.
How agencies and SaaS teams use this pattern
For a software agency, the win is repeatability. The agency curates two or three SKILL.md files (client portal, internal admin tool, public landing page) and every project starts from the same conventions. Claude Code applies the Skill; Totalum ships the result. The first hour of every engagement disappears, and the agency's house style, accessibility defaults, and analytics setup ship by default. We laid out the deeper picture in our overview of the best AI coding agents in 2026, where Skills plus a production runtime is one of the four patterns we see repeating across teams.
For a SaaS team embedding an AI builder feature, the pairing is even more interesting. Your users do not run Claude Code locally; you do. A Skill is how you encode "this is how we want our users' generated apps to look and behave." The Totalum API and MCP server are how those generated apps actually get built, hosted, and managed in production. You ship a Lovable-style or Bolt-style experience without rebuilding the runtime, the database, or the deployment pipeline. The Skill is your control plane.
For solo founders, the pattern collapses the distance between a Friday-evening idea and a Monday-morning demo URL. You write a one-page SKILL.md, drop the Totalum MCP server into Claude Code, and let one session do the boring parts.
How Claude Code Skills compare to other AI coding agents
Skills are an Anthropic-side concept, but the pattern travels. Other coding agents have parallel surfaces with different names:
- Cursor's prompt files and Composer presets play a similar role inside Cursor. We covered Cursor's cloud-agent side in our Cursor cloud agents vs Totalum post, including how the May 13, 2026 dev-environment release changed the landscape.
- Codex's project-level instruction files and the new sandbox controls on Windows behave like very small Skills with stricter execution guarantees. The Codex on Windows plus Totalum guide walks through both sides.
- Claude Code without Skills is still strong; with Skills it becomes shop-specific. Our head-to-head, Claude Code vs Codex in 2026, explains which one to start with based on your team's existing tooling.
- The MCP integration story is the connective tissue between any of these agents and Totalum. The Claude Code MCP tutorial is the simplest place to start if you have never wired one up.
The short version: pick the agent your team already uses, give it a Skill (or a Skill-equivalent), and add Totalum as the production runtime. The architecture stays the same regardless of which agent you start from.
FAQ
What is a Claude Code Skill in one sentence?
A Claude Code Skill is a folder containing a SKILL.md file plus optional helper scripts that Claude Code loads automatically when the current task matches the Skill's stated purpose.
Do Skills work inside Claude Code, or only in Claude.ai?
Both. In Claude.ai and the Claude mobile app, Anthropic's hosted Skills run inside Anthropic's sandbox. In Claude Code, Skills are filesystem-based and run on whichever machine Claude Code is running on (your laptop, a CI runner, a Vercel Sandbox, or a Totalum-managed runtime).
What is the difference between a Skill, a tool, and an MCP server?
A Skill is reusable knowledge ("here is how we do X in our shop"). A tool is a specific action Claude can take. An MCP server is a hosted bundle of tools (and sometimes resources and prompts) that Claude connects to over the Model Context Protocol. Skills can call tools; tools can be served by MCP servers; MCP servers are how the outside world becomes addressable from Claude.
Can a Skill deploy an application?
Not by itself. A Skill describes the steps; the actual deploy needs an action. With the Totalum MCP server wired in, the Skill's final step is a single MCP call that creates the project, builds, and deploys, ending with a real URL.
How does this compare to running a Skill on Vercel Sandbox?
Vercel Sandbox is the strongest answer when you need ephemeral compute or many isolated runs of the same Skill. Totalum is the strongest answer when the Skill needs to produce a deployed application with auth, a database, and a domain that survives the session. The two are complementary; in many setups the Skill runs the build inside a sandbox and the final deploy step lands in Totalum.
Is "claude code skills" the same thing as "claude agent skills"?
Almost. "Claude agent skills" is the wider Anthropic term across Claude.ai, Claude mobile, and Claude Code. "Claude code skills" specifically refers to the filesystem-based Skills you use inside Claude Code. The mechanics are the same; the loading surface differs.
How fast is the Skills ecosystem growing?
Faster than any other category in the AI coding space we are tracking. The parent term "claude skills" went from roughly 10 monthly searches in May 2025 to 27,100 in March 2026 according to Google keyword data. Community Skill repositories on GitHub (including widely-followed lists with 300+ entries) launched in the same period and continue to expand weekly.
Ready to build with Totalum?
If you are a developer or founder who wants to try the Skill plus Totalum pattern on a real project, the fastest path is to create a free Totalum account, drop the Totalum MCP server into your Claude Code config, and let your next Claude session ship a real app instead of a folder on your disk.
If you run a software agency or a SaaS team and want to talk through embedding this pattern into your own product (or into your client deliverables), book a 30-minute call. We will walk you through the API, the MCP server, and the agency or SaaS embedding setup that fits your stack.