Building an MCP Server Inside Your Rails App
A hands-on guide to exposing your Rails app's data and actions to AI assistants with the official Ruby MCP SDK: tools, authentication, Streamable HTTP and testing.
Software that works, by the date you need it.
Event software, connected hardware and web products, built on a fixed scope by a senior engineer. AI speeds up the work. Fifteen years of experience keeps it rock solid.
I'm Wagner Matos, based in Dorset and working remotely across the UK, US and Europe. Past clients include Johnson & Johnson, GSK, Citizens Advice, Babbel and Carwow.
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Building for a congress stand?
Touchscreens, photo experiences and stand analytics, on the floor when the doors open.
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The cloud, updates and remote access for devices on networks you do not control.
How it works
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Step 1
A short call
Thirty minutes, free. Enough to tell whether I can help.
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Step 2
For bigger builds, one week turns your idea into a spec, an architecture and a fixed price.
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Step 3
Build, launch and support
Working software at every milestone, then deployed, documented and supported.
Not a build? I also take contract engagements and fractional support. More on the services page.
What clients say
When we hand Wagner a build with a hard deadline - a congress opening, a live event - it ships. Complete, working, on the floor when the doors open.
Wagner was enjoyable to work with. He was able to quickly get up to speed, immediately wrapping his brain around problems and shipping clear code to fix them.
Wagner handled our blog migration end to end including migrating all content, URLs and redirects for SEO, and a custom Cloudflare Worker. All documented and deployed with zero drama.
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A Rubyist's guide to uv, the fast Python tool that covers what Bundler, rbenv and gem-installed CLIs do in Ruby, with direct command mappings and a working Flask setup.
How I run production infrastructure as a one person consultancy
Anyone hiring one engineer has the same question and almost nobody asks it: what happens after he leaves? This is the honest answer. The two hosts, the checks that run on them, the tool I built to close the two gaps nothing else covered, and what 'supported after launch' actually means when one person is on the hook.
AI accelerated, senior led: how I actually use agentic tooling
Buyers of AI built software all ask the same question: who checks it? This is my honest answer, using Interlock, the approval gate I am building for my own automated work, as the worked example. Not may I run this, yes or no, but here is a draft, fix the second paragraph, ship what I edited.
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Recent Work
Citizens Advice
Citizens Advice helps millions of people a year with debt, benefits, housing, consumer and energy problems. Casebook is the Rails application its advisers use to do that work: every client, every case, every appointment, across the national network. I joined the engineering team as one of several senior developers and worked on the core of it.
Johnson & Johnson
During the ECP Congress 2025, Johnson & Johnson needed a way to bring their precision medicine story to life on the exhibition floor. Healthcare professionals would be passing through quickly, the experience had to attract, educate, and track engagement, all without depending on venue Wi-Fi or cloud infrastructure.
Confidential (healthcare)
I built a serverless webhook service that delivers real-time conversation events to each NHS trust's own systems, handling encryption, authentication, concurrent delivery, and automatic retries.
Johnson & Johnson
For Johnson & Johnson Medical Affairs at a major international medical congress in 2025, I built an interactive presentation kiosk that works with no network at all, and still hands the team a full picture of what visitors looked at, for how long, and how far they got. The fourth build for the same client team, across three congresses.