Spellbook is Disney's design management system. Component library, design tokens, contribution guidelines — one source of truth for the UX and engineering teams that ship the product surfaces underneath the streaming and media division.
What it is
A React + TypeScript component library, paired with a Figma library and a tokens layer in SASS. Storybook for documentation and visual review. The components are the artifact most people see; the contract that holds them together — token names, prop signatures, accessibility requirements — is what makes the library usable across teams that don't talk to each other every day.
How teams use it
Design and engineering meet weekly. Proposals come in from product teams, get triaged, get specced, get implemented in the open. New components ship with tests, accessibility audits, and Figma parity. Existing components evolve with version bumps and migration notes — no silent API drift.
That cadence is why Spellbook is still maintained years in. A design system without a forum becomes shelfware in eighteen months. Spellbook has the forum.
My contribution
I worked on Spellbook in two passes. The first pass was foundational — helping define the contracts that make a multi-team library usable: token naming and theme structure, component API conventions, and the accessibility checklist every component had to clear before merge. Those are the boring pieces that decide whether ten product teams can ship against the same library without coordinating every change.
I then rotated to a sibling group to build the Elsa Design System for the ABC Television and streaming properties — same playbook, different surface, five themes across seven applications. Coming back to Spellbook with that scale-out experience, I contributed to component reviews, governance and contribution-handbook revisions that lowered the friction for product-team PRs, and the migration patterns we used to evolve the library without breaking consumers.
The dual loop — leave, build something adjacent, come back with new lessons — is one of the things that's kept the library honest. New patterns get tested against real product needs, not just designer aesthetics.
What it shipped
10+ Disney applications use Spellbook in production today. The number isn't the headline; the headline is that it's the fastest way for those teams to ship features with consistency. When the system is the path of least resistance, adoption stops being a sales problem.
Why this matters for AI systems
Spellbook taught me a lesson I now apply to every AI engagement: the thing you're shipping isn't the component, the pattern, or the prompt. It's the system that keeps those things consistent when ten people — or ten agents — are building on top of it at the same time.
Agent architectures at production scale hit the exact problem Spellbook solved for design: without a shared vocabulary (tools, prompts, eval harnesses, trace formats), every team invents its own, and the organization can't tell whether any of it works. The answer is the same — pick your components early, document them, and make the system the fastest way to ship.