Dmytro Gaivoronsky

🇺🇦 🇺🇸 Engineering leader & builder. 25+ yrs in tech including Google, AWS, and Meta.

3 minute read

I’ve been a member of The Mountaineers for a few years now. I’ve taken a few courses, climbed a few peaks, gone on a bunch of activities, and made a few friends.

At some point I also started building little tools around the site: a Chrome extension that syncs my activity history, a CLI for PeakBagger, and a Claude Code plugin that pulls route beta from a few places. Same itch every time: I want the data without clicking through five tabs.

The missing piece was letting an AI assistant query mountaineers.org directly. A lot of that site is public for anyone to browse. MCP just turns those pages into structured results so Claude/Codex can answer questions like “what scrambles are on the calendar?”

If you’re a Mountaineers member, the same idea gets more useful: you can ask about your own registrations, activity history, and course enrollments.

Demo

Getting to a working prototype

I skimmed the Model Context Protocol spec, looked at mountaineers.org, and thought: it’s mostly HTML. I can parse it, wrap it as MCP tools, and call it done.

That part did go quickly, mostly because I didn’t do it alone. I built it with a lot of help from Claude Code and Codex, and it stayed fun the whole time. I had a usable prototype in TypeScript the same day, published it on npm, and had it answering questions in Claude Desktop.

The slow part was all the small, undocumented details. The site runs on Plone, and a bunch of the “API-shaped” surfaces aren’t APIs at all:

  • Faceted search returns HTML fragments, not JSON.
  • “My Activities” is a React component with JSON stuffed into a data-props attribute.
  • Logging in means grabbing a CSRF token from a page and then POSTing it back.

I wasn’t expecting any of this to be documented. It was mostly poking around in DevTools, trying a few requests, and seeing what broke. I also borrowed patterns from the Chrome extension.

What It Can Do

Right now it’s split into public tools (no login) and authenticated tools (your account).

Public tools:

  • Search activities by type, branch, difficulty, date
  • Search courses, trip reports, and routes
  • Get full details for any activity, course, trip report, or route

Authenticated tools:

  • Your upcoming activities and course enrollments
  • Completed activity history with filtering
  • Earned badges and certifications
  • Member profiles and activity rosters

The public tools are basically a convenience layer over information anyone can see on the website. The authenticated tools are where the personal stuff lives.

Example Session

Two real screenshots from Claude Desktop:

Upcoming courses with open spots

Claude Desktop showing a course summary generated from Mountaineers data

One activity, with the details pulled into a single view

Claude Desktop showing activity details generated from Mountaineers data

No clicking around. No manually redoing the same filters.

The first cut was messy

The first version was useful but rough:

  • Some list tools returned bare arrays, so the client couldn’t tell when results were truncated.
  • Some detail pages had fields I wasn’t extracting yet.
  • Filters were inconsistent across endpoints.

I pushed a cleanup pass here: ListResult<T> wrappers for truncation, multi-leader extraction for activities, structured date parsing for courses, plus more filters across the list tools. That work is in this PR.

At one point I kept asking Claude to “do better,” and it responded by writing 200+ tests. Turns out HTML parsing breaks in quiet ways. One template tweak can turn “works fine” into “returns an empty list” and you don’t notice until you ask at the wrong time.

Using it

If you want to use it, it works in Claude Desktop, Claude Code CLI, and Codex CLI. The README has the current install/run instructions:

You can’t use it in ChatGPT Desktop without hosting infrastructure that runs the server and proxies a logged-in session to mountaineers.org. That would mean building something that can see your credentials. I don’t want to ship that.

Your credentials stay on your machine and are only sent to mountaineers.org. Nothing goes to any AI provider.

If you find bugs or want features, open an issue.

Cheers.

Updated:

Comments

You May Also Enjoy

Where the Work Goes When Agents Arrive

7 minute read

A friend dropped this in our Slack the other day about Steve Yegge’s Gas Town: I think Gas Town is directionally correct but you have to admit also unhinged in a bunch of ways. I can’t help but be attracted to the absolute gonzo yolo mentality that birthed it, but I wouldn’t want to live there. It’s been rattling around in my head since. He’s right on both counts. And I say that as someone who actually lives there. The main thing I keep noticing isn’t the tools. It’s where the work goes. Over the last six months living in Gas Town, the biggest shift hasn’t been speed, it’s attention. This post is about how that attention moves upstream into design and guardrails, and how the feedback loops change once you stop reading every line.

How I Stopped Losing Track of Side Project Ideas

3 minute read

I’ve been using Claude Code and Codex a lot lately, and something unexpected happened: I started having more ideas than I could track. Not because I’m suddenly more creative. Because building stuff got faster. When you can go from “I wonder if…” to a working prototype in an afternoon, you start noticing more itches worth scratching. A dashboard for ski conditions. A break-even calculator for EV charging. A CLI for searching mountain peaks. A lot of these are afternoon builds. Some would take weeks. A few will never happen. But I kept losing them, scattered across Notion pages, random notes, half-remembered thoughts.

EV vs Gas Break-Even Calculator

2 minute read

Yesterday we were driving up to Snoqualmie Pass to ski with the family, and I realized I’d forgotten to charge the Rivian overnight. So we had to stop in Issaquah and top up at Electrify America, going from about 10% to 85%. The price there was roughly $0.56/kWh, which naturally turned into a conversation with my dad about how charging a Rivian really compares to fueling a gas car. We came up with some rough numbers on the spot, but I was curious what this actually looks like in perspective.

Session Topic Summaries in Claude Code Status Line

2 minute read

A couple of months ago I realized I run way too many parallel Claude Code sessions. Some are rapid-fire sessions where I’m iterating on code quickly. Others are slow burners that sit around for days while I context-switch to other work. The problem: when you come back to one of those slow sessions, you get that familiar moment of staring at the transcript thinking, what was I doing here again? Claude Code doesn’t help. There’s no at-a-glance “this session is about X” indicator. You end up scrolling up, re-reading, trying to reconstruct context like you’re debugging your own brain. So I built a thing.