Cursor, Codex, and Copilot All Ship Side Chats

Three coding tools shipped the same fix: branch a side conversation without losing the main agent thread. Codex CLI, Cursor, and VS Code Copilot each added it within weeks of each other.

That matters for anyone building agent tools. A long agent run holds one expensive context, and a side question asked in the same thread risks polluting the work you're paying for.

Codex CLI's version, 0.146.0, is the most complete of the three, per the release notes. It adds named sessions, thread pinning, and forked threads with paginated history. It also lets you switch between side conversations without closing the one you're in.

Cursor 3.11 added the lightest version of the fix: two shortcuts, /side and /btw, for quick detours, per its release notes.

VS Code Copilot went further: one session holds multiple chats with peer-chat forking, so a branch can spawn its own branch, per its update notes.

Branching a chat without losing the main thread is the floor for coding agents, not a feature to brag about. A tool that ships a long-running agent mode without it looks like it's missing something basic.

The three releases surfaced together in the July 31 briefing on coding-agent updates.