Mastra would be a good addition to the Better-T-Stack as it already scaffolds TypeScript solutions for frontend, backend, native and DB but it is missing agent frameworks and tooling.

A new folder called agents can be used to contain Mastra and other TS AI tools.

Mastra has its own CLI: https://mastra.ai/en/docs/getting-started/installation

It can be deployed as its own Hono server with out of the box UI for observability or deployed inside a separate backend route such as a Nextjs serverless function: https://mastra.ai/blog/nextjs-integration-guide