Claude Fable 5 model, Cursor cloud agents, and Codex CLI relays for daily builds

Claude Code rolled out the Fable 5 model and deep sub-agent nesting while Cursor and Codex added cloud execution and CLI handoffs across the week.

Across this week from 12 June 2026 to 19 June 2026, three coding platforms released updates focused on agent depth, cloud execution, and CLI controls. Claude Code shipped the largest set of changes including a new Mythos-class model and permission rules. Cursor and OpenAI Codex followed with SDK extensions, design…