Sonnet 5 and Opus 5 by default, thread activity in the bell, and floating miniapps

The curated model picker now starts you on the current generation of Claude, thread replies finally show up in the Activity bell, and miniapp surfaces can float outside the panel they were pinned to.

Sonnet 5 and Opus 5 by default

The curated model picker defaults to Sonnet 5 and Opus 5, so new workspaces and anyone who hasn’t set an override start on the current generation instead of an older default.

Thread replies reach the Activity bell

If you’re a participant in a thread, replies to it now notify you through the Activity bell. Previously thread activity could pass entirely unnoticed unless you happened to have the thread open. Copying a link to a message inside a thread now carries the thread context with it, so the link opens where you meant it to.

Miniapp surfaces that float

A live miniapp surface can float free of its panel, so you can keep an app visible while you work elsewhere in the window. Behind that, packages can host their own MCP servers without going through the managed store first, generate starter identities when scaffolding, and use a new set of public orchestration primitives. The SDK gained an authoring compiler with a proper lifecycle for people building packages.

Images in messages

Published image attachments render at a usable size rather than being shrunk to a thumbnail, and a gallery you composed keeps the layout you gave it instead of being reflowed on send.

Specialists recover instead of failing

A specialist request that overflows the provider’s payload limit now recovers rather than dying, since request sizing is measured in bytes rather than estimated. Routing and dispatch recover from a transient unavailable state instead of leaving the turn stuck, and a “Built In” provider failure is reported as a platform-side problem rather than blaming your credentials.

Polish & fixes

DM names survive a workspace switch. The voice dock holds its geometry, and a voice session that fails while idle now tells you instead of silently doing nothing. Selecting text to annotate works correctly again after the 2.1 annotation release. Browser no longer leaves orphaned render layers behind, and the updater window focuses properly instead of timing out in the background.

Course tasks honor their configured model preference. This release also carries the second and third stages of the platform Directory migration — user identities are now canonically owned in one place, with the legacy fallback removed — plus a build-performance pass that shortens cold starts.