Background session socket waits for new connections to speak before letting them in

What

A background session is a Claude Code session that keeps running while you are not watching it, and you attach to it through a local socket (a connection point on your machine). Before, every new connection to that socket replaced the current one at once, so a stray connection could kick out the client you had attached.

• New connections now stay unadmitted until they send a first line.
• Unadmitted connections that send nothing are closed after a timeout, set by CLAUDE_BG_SILENT_PEER_TIMEOUT_MS.
• The old let-in-at-once behaviour applies when CLAUDE_BG_SOCK_ADMIT_SILENT_PEERS is "1", or when there is no auth token and no other condition holds.
• A new helper sets CLAUDE_BG_SOCK_ADMIT_SILENT_PEERS to "1" in the environment it is given, and deletes it instead when the remote switch bot_protected_tengu_merry_bear is true. Which environment it is applied to was not found.

Nothing has been read about the tengu_merry_bear switch yet.

Why

When the new rule is in effect, a probe or a connection that never speaks can no longer throw your attached view off a background session. Whether it is in effect depends on that variable, which the new helper sets to "1" unless the remote switch is true.