Pydantic AI Updates: August 12, 2026

1. Pydantic AI v2.28.0 Adds Realtime Speech-to-Speech and a Crusoe Provider

Pydantic AI. Pydantic AI v2.28.0 introduces realtime speech-to-speech support through a new Agent.realtime() API, including browser WebRTC with server sideband support for live voice conversations. The release also adds a Crusoe AI provider integration and ships bug fixes for Bedrock cache handling, realtime reconnection state, and AG-UI tool-call serialization. The realtime API brings low-latency voice agents into the framework without a separate stack. Source

2. Pydantic AI Patches a High-Severity Web Chat UI Vulnerability

Pydantic AI. Pydantic AI fixed a high-severity vulnerability in its development web chat UI, where the chat endpoint accepted requests without content-type validation, allowing a cross-origin request from a website open in a developer’s browser to trigger agent execution with local system privileges. The fix, shipped in v2.28.0 and backported to the v1 line as v1.107.4, now requires a Content-Type: application/json header before processing. The backport also redacts retry-prompt content when InstrumentationSettings(include_content=False) is set. Source