Sendero

Inspiration

This August one of my best friends visited me from Sevilla, I live in Buenos Aires. We've known each other since high school and both moved abroad 10 years ago. Since then we've lived an ocean apart, but connected. Last moth I got the joy of being physically in the same space as me, for two weeks. Me as a good Leo planned the whole itinerary for each day. I was hesitant at first but I gave ChatGPT the chance to build an itinerary based on: places I wanted them to visit, places they wanted to visit, some underground recommendations I asked for. I was quite surprised with the result, it managed to gave me a very details and packed itinerary that made sense, it managed every constraint I gave it, and it even took the weather into consideration. But the cerry on top was, every event or place that required a ticket or a reservation, it told me. I was so happy I couldn't wait to share it with them. But then that moment came, and the only thing I had was a nice itinerary in marked up language that couldn't be understood when read through a WhatsApp message bubble. A bit salty about it and the fact that they made a little fun of that (don't get me wrong I enjoyed the humor but my ego wanted to prove me right) I decided to make a website so they can navigate the whole itinerary. My friend was impressed, but we couldn't actually get to used because I was too busy and tired to finish and publish the site, since we were always out, playing video games or taking or anything (catching up 10 years of being apart in two weeks). Then I learned about this challenge, I don't remember how. And the idea sparked, use this challenge as fuel to complete the website, make it better, throw it to the public, and be grateful to my best friend for even inspiring me to do this kinds of things, thanks to his visiting.

What it does

Sendero provides an structured way for ChatGPT to build an itinerary and the UI to present them in a more beautiful and accessible way (not to say better than and copied message from the chat). Also expands its capability by giving the user 3 types of viewing the itinerary: Activities by days listed 2) Activities by days in a calendar 3) Routes in maps per day. Also you have a centralized sections of all the reservations. It takes in account weather and local activities happening in the place your're visiting, making it a very well rounded itinerary.

How we built it

I built Sendero as a bridge between the conversation and the actual travel app. The traveler describes the trip normally, and ChatGPT uses eight WebMCP tools exposed by the page to load Sendero’s planning rules, pass the trip details, validate the result, and place a real draft in the browser. The traveler can review it as a list, calendar, map, or reservation checklist, and nothing is saved or shared until they explicitly request it.
The tools are registered with document.modelContext.registerTool, use closed JSON schemas, and connect to the same state and actions as the visible React interface. The public shared-trip page exposes six additional tools for navigating the itinerary without modifying the original trip. I still let myself vibe code it.

Challenges we ran into

Motion and transitions in the landing page. It's ok, but there is still some road to go.

Accomplishments that we're proud of

I had fun. I was happy.

What we learned

WebMCP, literally. I had no idea it existed until this challenge. Now I am in love.

What's next for Sendero

Itinerary searching liking and... disliking? Notifications Sendero badge for your website Sendero for business Real time collaboration?

Built With

• auth0
• convex
• google-maps
• gsap
• hono
• javascript
• json-schema
• model-context-protocol
• node.js
• react
• tanstack-query
• vercel
• webmcp