Pydantic AI v2 Lands With a Leaner Core and a New 'Harness'

Pydantic·medium signal

Pydantic released AI v2, advertising expanded capabilities, a slimmed-down core, and a new 'Harness' abstraction for running agents. The release continues Pydantic's push to bring its type-safety reputation to agent development, competing with LangChain and Microsoft's Agent Framework. The 'harness' framing echoes a broader 2026 trend of agent runtimes outliving any single model.