Runtype
Changelog
ImprovementJune 17, 20261 min read

Better email conversations and full HTML replies

Email agents preserve thread context, reply safely to the right audience, and can author sanitized, inline-styled HTML when Markdown is not enough.

emailsurfacesagentsmessaging

Email surfaces now behave more like a careful human participant while giving agents more control over presentation.

  • Scoped reply-all. Replies keep the original To and Cc audience while removing the agent's own addresses. Set replyRecipients: "sender" when a low-trust or unattended surface should answer only the sender.
  • Correct threading. Runtype carries the RFC 5322 References chain so Gmail, Outlook, and other clients keep replies in the original conversation.
  • Loop prevention. Automated mail, mailing lists, bounces, and no-reply addresses are suppressed before dispatch, and outbound replies carry standard auto-response headers.
  • Optional HTML authoring. Set an email surface's reply format to Raw HTML when the agent needs a complete, inline-styled email body. Runtype removes active content, event handlers, unsafe URLs, and CSS that can fetch remote resources before sending.

Markdown remains the default, token-efficient format and continues to render as constrained HTML automatically.