What T3 Code Is
T3 is the TypeScript ecosystem's most opinionated stack: Next.js, tRPC, Prisma, Tailwind, type-safe everything. T3 Code takes that same philosophy and applies it to an AI coding agent.
The result: a coding agent that understands T3-stack patterns specifically — not a generalist that tries to help with everything. When you're building a T3 app and you ask it to add an endpoint, it knows the right way to do it in your specific stack.
Why Opinionated Beats Generic
Generic coding agents produce generic code. When you're working with a specific, well-defined stack, a specialized agent that knows that stack produces dramatically better output than one that has broad but shallow knowledge of everything.
The same logic applies elsewhere: a Python/FastAPI-specialized agent will outperform a general agent for FastAPI development. A React Native/Expo agent will outperform a general agent for mobile. Specialization wins when you've already made your stack decisions.
Open Source Architecture Reference
T3 Code is worth reading even if you don't use the T3 stack. As a working coding agent implementation, it shows how production agent behavior is actually structured — prompt design, tool use, context management, constraint enforcement.
For developers building their own agent tooling or trying to understand how Claude Code-style systems work under the hood, this is a concrete reference implementation.