Mastra

Mastra is a TypeScript-based AI agent framework that provides developers in the JavaScript ecosystem with a comprehensive set of tools for building, observing, and iterating on intelligent agents. Its core components include agents, tools, workflows, and scorers: workflows are used to orchestrate multi-step tasks, while scorers evaluate the output of these agents, providing a factual basis for improvements rather than relying on subjective judgment.

It places observability in a very prominent position; during local development, users can see the input and output of each step, as well as the tool calls and their execution times. This makes it much faster to identify why an agent took the wrong path than to simply browse through logs. The system also supports MCP, allowing existing tool interfaces to be integrated into agents. The project is open-source on GitHub, and the community is active; the documentation and examples are relatively complete. It is suitable for teams that use Node/TypeScript to develop production-grade agents, but not for those who have no coding experience at all.