v0.4.0 Changelog

Added

• Expanded Artifact into a first-class Agent UI Artifact Workspace surface.
• Added artifact interaction contract covering artifact facts, workspace regions, cards, preview, edit/canvas, versions, diff, export, handoff, source links, and evidence links.
• Added specific artifact event classes to the public event schema: artifact.created, artifact.updated, artifact.preview.ready, artifact.version.created, artifact.diff.ready, artifact.export.started, artifact.export.completed, artifact.failed, and artifact.deleted.
• Added external research notes from Claude Artifacts, Vercel AI SDK UIMessage, assistant-ui attachments/tool UI, and OpenAI Apps SDK structured tool/widget boundaries.
• Added v0.4.0 version snapshots.

Compatibility

• Existing clients can keep consuming artifact.changed while adopting the more specific artifact lifecycle events.
• Agent UI remains an interaction standard, not an artifact storage or persistence protocol.