In January 2025, I published a package called Agent Toolbelt to npm. It's an MCP server — a collection of developer utility tools that Claude can use. UUID generation, base64 encoding, JSON formatting, timestamp conversion. Nothing groundbreaking. The kind of tools every developer reaches for daily.
Within weeks, it was getting over 1,600 weekly downloads.
npx agent-toolbelt
One command. Claude sees the tools. Developers use them. That's the entire distribution story.
I'm not telling you this to brag about download numbers — 1,600 is modest by npm standards. I'm telling you because it illustrates something about where we are in the MCP ecosystem: the bar for impact is low, and the surface area for opportunity is massive.
The ecosystem right now
Search npm for MCP servers. You'll find a few hundred packages. Now think about every category of software tool that exists: DevOps, databases, APIs, file management, cloud infrastructure, communication, analytics, CRM, project management, design, security, monitoring.
Most of these verticals have zero or one MCP tool package. Many have none.
Compare that to npm overall — over 2 million packages — and you see the gap. The MCP tool ecosystem is where the broader npm ecosystem was in 2012. Early. Wide open. Growing fast.
Where the gaps are
Verticals where MCP tools are either nonexistent or severely underbuilt:
Developer tools
- Git operations beyond basic commits
- Docker and container management
- CI/CD pipeline interaction
- Cloud provider CLIs (AWS, GCP, Azure)
- Database query and migration tools
Business operations
- CRM integration (Salesforce, HubSpot)
- Project management (Jira, Linear, Asana)
- Communication (Slack, Discord, email)
- Document generation (contracts, reports, invoices)
Data and analytics
- Database querying and visualization
- Spreadsheet operations
- Data pipeline management
- Business intelligence dashboards
Domain-specific
- Healthcare data (FHIR, HL7)
- Legal document analysis
- Financial compliance checking
- Real estate listing management
- E-commerce inventory and pricing
Each of these is a potential MCP server. Each could be a published npm package. Some of them could be products.
Three levels of opportunity
Not every MCP tool needs to be a business. There's a spectrum:
Level 1: Open source package
Publish a free tool to npm. Build reputation. Get downloads.
Example: Agent Toolbelt. Free, open source, 1,600+ weekly downloads. It established credibility, led to a course, and serves as a working reference implementation.
Time investment: A weekend to build, an hour to publish, minimal maintenance.
Returns: Reputation, GitHub stars, npm downloads, proof of expertise. Career assets that compound.
Level 2: Hosted MCP server
Take your tools and host them as a remote service. Users connect over HTTP instead of running locally. Add authentication, usage tracking, and premium features.
Example: A hosted stock analysis server. Free tier gives 10 queries/day. Paid tier ($19/month) gives unlimited access plus premium data sources.
Time investment: A few evenings to add HTTP transport, auth, and deploy.
Returns: Recurring revenue. 50 subscribers at $19/month is nearly $1,000/month.
Level 3: Full product
A complete application powered by your MCP tools. Web UI, user accounts, billing. Your tools become the backend engine.
Example: A financial analysis platform. Users interact through chat. Behind the scenes, Claude calls your MCP tools to fetch data, run calculations, generate reports.
Time investment: Weeks to months.
Returns: A real product business.
Start at Level 1. Validate the idea. Move up the stack if demand is there.
The revenue math
Let's get concrete about what a side-project MCP tool business looks like.
Scenario: Hosted MCP server for a niche vertical
- Build time: 2-3 weekends
- Hosting cost: ~$5/month
- Pricing: $19/month per user
- Marketing: 1 Dev.to post + npm package as funnel
| Subscribers | Monthly | Annual |
|---|---|---|
| 10 | $190 | $2,280 |
| 25 | $475 | $5,700 |
| 50 | $950 | $11,400 |
| 100 | $1,900 | $22,800 |
These are small numbers compared to a VC-funded startup. They're meaningful numbers for a side project built in a few weekends.
And the distribution advantage is real: your free npm package funnels users to your hosted offering. Every npx your-tool is a potential conversion.
Why now
Three things converging:
1. The protocol is stable enough. MCP has been through enough iterations that tools you build today won't break tomorrow. Anthropic is actively developing it. Other companies are adopting it.
2. The clients are ready. Claude Desktop supports MCP natively. VS Code extensions are adding support. More clients are coming. Your tools work everywhere.
3. The ecosystem is early. In a mature ecosystem, you're competing with established players. Right now, you're planting a flag in unclaimed territory. First-mover advantage is real when total MCP packages are in the hundreds, not millions.
If you wait a year, the landscape will look different. The verticals will have incumbents. The easy wins will be taken. The window for outsized impact relative to effort is right now.
What I'd build if I were starting today
If I were picking a vertical to build MCP tools for right now, here's how I'd think about it:
- Pick a domain you know. Your industry knowledge is the moat, not the code.
- Find the API. Almost every vertical has REST APIs you can wrap. That's all an MCP tool is — a function that calls an API and returns structured data.
- Start with 3-5 tools. Not 50. A small, focused toolkit that does one job well.
- Publish to npm. Get the feedback loop going. See if people use it.
- Write about it. One Dev.to post about what you built gets more distribution than any other marketing effort at this stage.
The developer who builds the definitive MCP toolkit for [your vertical] is going to be in a very good position. That developer could be you.
This is Part 3 of a free 3-part series on MCP.
If you want to go from "I understand the opportunity" to "I shipped a real MCP package," that's exactly what the full course covers:
- Module 1: Build your first MCP server and connect it to Claude
- Module 2: Build real tools that call APIs and chain together
- Module 3: Production patterns — error handling, caching, testing
- Module 4: Package and publish to npm with CI/CD
- Module 5: Turn your tools into a hosted product
- Module 6: Advanced patterns — resources, prompts, multi-server
7 modules. 33 lessons. Ship a real npm package by the end.
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