coder/xum v0.28.3

on GitHub

This release promotes Claude Fable 5.1 and Claude Mythos 5.1 (launched by Anthropic today) as the default fable and mythos models, and adds Z.ai as a native provider.

Models

• Claude Fable 5.1 as the new fable model, with launch-verified pricing including the 75% cheaper cache reads ($0.25/M)
• Claude Mythos 5.1 as the new mythos model (trusted-access)
• Fable 5 and Mythos 5 remain usable as custom model strings, keeping their metadata and tokenizer approximations; existing fallback chains are preserved with one-shot reseeding to the 5.1 chain
• Z.ai as a native provider with GLM 5.3 Flash

Workflows & agents

• Durable workflow runs render as live cards in chat and the workspace UI
• Terminal wakes for kernel-launched background workflow runs, and compact machine events for background workflow-result wakes
• Intra-tree agent peer messaging via task_send_message, workspace archive/unarchive via task_workspace_lifecycle, and agentId on workspace tasks

Reliability

• Self-heal corrupt analytics rows and stop a single corrupt persisted row from bricking workspace fetch
• Exit wakes when monitored background bash settles, no more silent bash monitor retirement, and fixed release preparing after superseded monitor wakes
• Blocked duplicate workflow_run launches of an active script

Performance & UI

• Scoped workspace activity lookups and archived workspaces excluded from project listings
• Mobile timeline dialog, model selector dropdown clamped below the top bar, and iOS 26 PWA header fix