Tools with a contract
Every tool declares what it takes and what it returns (inputSchema and outputSchema), so the assistant doesn't guess and a malformed answer is caught before it reaches your team.
MCP · ChatGPT · Claude · updated: Oct 2026
Custom MCP servers so AI can work with your system
I build MCP servers that let ChatGPT, Claude and other assistants query and act on your app, store or internal API with each user's permissions. US$1,990–US$3,990 per project, fixed price, remote from Mexico City.
5-day assessment · US$590, credited if you hire me
What an MCP server is, and when it's worth it
The Model Context Protocol (MCP) is an open standard for connecting AI assistants to systems. An MCP server exposes a handful of tools ("find order", "customer balance", "stock by location") and the assistant decides which one to call to answer your question, with the permissions you defined. The answer comes from your system, not from the internet.
Your team copies data out of your app, store or spreadsheets to paste into ChatGPT, and everyone does it differently.
You want to ask Claude or ChatGPT "which orders are still unshipped?" and get the answer from your system, not from the internet.
You run a SaaS or an internal API and want assistants to use it with each user's permissions, not a master key.
You tried a generic connector and it knows nothing about your business rules.
When it isn't
- If what you need is the same report every week, a plain report is cheaper than an MCP server.
- If your data can't go to an AI provider at all, an MCP server alone doesn't solve that.
What every server includes
Per-user permissions
The assistant sees what the user can see in your system, not one row more. Keys and access belong to your company.
A person approves the irreversible
Reading is free; payments, refunds, deletions and emails to customers go through a human. Limits live in code, not in a prompt the model can ignore.
Local or on your server
stdio for Claude Desktop, Claude Code or Cursor, or stateless Streamable HTTP behind your proxy: listens on loopback, validates Host and Origin and requires a token.
Every call is logged
Each request is recorded so you can see what the assistant asked, what your system answered and why.
Tests, and the code is yours
Tests for every tool and a smoke test that calls all of them before handoff. The code lives in your repository from the first commit.
Price, and where it starts
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Day 0
Free 20-minute call
You tell me what system you run and what you want to ask it. If an MCP server isn't the answer, I'll say so on the call.
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Days 1-5
Assessment
US$590, fixed price: which tools the server needs, what data they touch, who can use each one and the fixed price to build it. Credited in full if you hire me.
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Then
Fixed-price build
Scope written as results you can check, tested against your real questions before your team connects to it.
Build: US$1,990–US$3,990 per project. Model spend is billed separately by the AI provider, measured in the first week of production and capped monthly. I'm in Mexico City, on Central Standard Time all year, and work in English.
Three MCP servers I've already shipped
They are open source, published on npm and in the official MCP registry, and anyone can read how they're built: strict TypeScript, typed output, both transports and tests in CI.
17 tools
seo-geo-mcp-server
Audits SEO and whether ChatGPT, Claude, Perplexity or Gemini can read and cite a page.
19 tools
domain-security-mcp-server
Audits email and domain security: SPF, DKIM, DMARC, DNSSEC, TLS and blocklists.
8 tools
mx-fiscal-mcp-server
Validates Mexican RFC, CURP, CLABE and NSS, parses a CFDI 4.0 invoice and checks its status with the SAT.
What I write about MCP: the best MCP servers for SEO, an MCP server in Laravel, step by step and migrating to the 2026-07-28 revision.
Questions before we start
What is an MCP server?
The Model Context Protocol is an open standard that lets assistants like ChatGPT or Claude query and act on your system with the permissions you define. An MCP server exposes a few tools, and the assistant picks which one to call to answer a question in plain language. The answer comes from your data, not from the internet.
How much does a custom MCP server cost?
US$1,990–US$3,990 per project, fixed price, depending on how many systems it connects to and how many tools it needs. It starts with a 5-day assessment for US$590, credited in full if you hire me for the build. Model spend is billed separately with a monthly cap.
How long does it take?
I don't publish a fixed build time, because it depends on how many systems the server touches. The assessment does have one: 5 business days, and it ends with the fixed price for the build.
Does it work with both ChatGPT and Claude?
Yes: MCP is an open standard, not tied to one vendor. The same server connects over stdio to local clients such as Claude Desktop, Claude Code or Cursor, or over HTTP when it runs on your infrastructure.
Can the AI change or delete data on its own?
Only if you decide it can, and never anything irreversible without a person approving it. Tools are read-only by default; the ones that write carry their limits in code, and every call is logged.
Can you build it in Laravel or PHP?
Yes. With the laravel/mcp package the server lives inside your application and the package handles the protocol; there is also an official PHP SDK, still experimental. If the app is old and fragile, it may be worth stabilizing it first, which is what the legacy Laravel and PHP rescue is for.
Which protocol revision do you target?
The 2026-07-28 revision, the one that made the protocol stateless, without locking out 2025 clients. My three open-source MCP servers already serve both.
Who owns the code?
You do, from the first commit: it lives in your repository and your accounts. If we stop working together, you keep everything.
Tell me what you run and what you want to ask it
Two lines are enough. I'll tell you whether an MCP server is the answer or whether there's a cheaper way to get there.
07 / Contact
Tell me about your system and I'll tell you what I'd connect.
Fill out the form and I reply within 1 hour during business hours and within 24 hours outside them. You can also email me directly: