Pydantic AI is a Python-first, type-safe agent framework that leverages Pydantic's validation layer to enforce structured inputs and outputs across LLM interactions. Agents are defined with dependency injection, typed run contexts, and composable capabilities (tools, hooks, MCP clients/servers, A2A). It integrates natively with Pydantic Logfire for OpenTelemetry-based tracing, cost tracking, and eval-driven monitoring. The framework supports async streaming, graph-based multi-agent workflows, durable execution backends (Temporal, DBOS, Prefect, Restate), and agent definitions via YAML/JSON.