v0.42.0

What's New in v0.42.0

Features

• Responsive Skills Manager — narrow panes now show a usable one-panel list/detail flow with back navigation and unsaved-edit protection, while wide panes keep the familiar split layout. (#571)
• Peer-owned artifact presentation — plugins can register namespaced artifact providers with declarative actions instead of reaching into Agent Threads views or DOM. (#574)
• Public artifact lifecycle API — peers can allocate host-owned storage, attach artifacts to threads, open them, and invoke actions through API v1; thread deletion cleans up owned storage. (#576)
• Contributed agent tools — peer plugins can add isolated, bounded in-process tools to new Claude and Codex sessions, with host-injected thread identity, collision protection, and permission-aware support APIs. (#577)
• Contributed slash commands — enabled peers can add commands to the composer, Agents List, and Agent Board with live registration/disposal and safe draft recovery on failure. Built-in Design now exercises the same public path. (#578)
• OAuth resource indicators — MCP OAuth now supports RFC 8707 resource audiences across authorization, token exchange, and refresh, enabling servers such as v0 that require them while rejecting unrelated advertised origins. (#580)

Improvements

• More room to edit skills — Save, Reveal, Reload, and Uninstall actions now live in the detail header instead of consuming editor height below the document. (#575)
• Smaller Codex raw logs — repetitive diff snapshots, plan deltas, and command-output updates are compacted with bounded diagnostic tails while authoritative completed records remain unchanged. (#581)
• Documented modular architecture — ADRs now record the peer-plugin contribution strategy, orchestration ownership boundary, and namespaced artifact-provider model. (#572)
• More faithful visual tests — the screenshot harness now matches the real host's view-content layout, preventing misleading compressed Skills Manager editor baselines. (#573)

Notes

• No manual migration is required.
• Existing built-in Design behavior remains available in this release; the separate Design-plugin extraction was intentionally not included.
• Existing MCP OAuth connections that were granted without a resource audience may require one reauthorization if their authorization server rejects adding resource during refresh.
• Codex compaction applies to new log events only; existing JSONL logs are not rewritten, and compaction is not a total file-size cap.