FullCalendar WebMCP

Inspiration

I mainly got inspired because two of the projects I developed for a couple of small businesses use FullCalendar (React), so I was hoping to add agent functionality for scheduling. This was the perfect opportunity and the perfect tool.

What it does

Exposes six tools for reading calendar context, finding events, and reading individual events, and interact with them to create, update, and delete.

How we built it

I used AI agents like Codex and Cursor. I did have experience with the FullCalendar implementation, what I did not have experience with was Chrome-specific or Chromium-specific developer tooling.

Challenges we ran into

The hardest challenge was to contain the boundary between the adapter and the host application because it could really easily outgrow and become opinionated about the implementation, which is contradictory to the ergonomics I'm looking for.

Coding agents have this tendency that makes us overbuild, so I actually created three implementations before actually trimming about 60% of features I'd say, before freezing.

Accomplishments that we're proud of

I think is easy to understand, and it can be very developer-agent-friendly.

What we learned

I learned that less is more and clarity is the best way to communicate a tool description for agents. I mean, AI has come so far that it can pretty much understand intent even if you mess up your prompts.

What's next for FullCalendar WebMCP

I think this implementation can grow as an open-source project, especially since FullCalendar is used in production by many devs (9M+ monthly npm downloads). And not only FullCalendar, I actually bought a domain called protocoltooling.com that I probably would like to convert to a webmcp-focused tool creation organization for widely-used web-integrations like FC.

Built With

• chatgpt
• chrome
• codex
• cursor
• fullcalendar
• next.js
• npm
• react
• typescript
• vercel
• vite
• webmcp