[Bug] Rating prompt triggers in fork subagents and deadlocks them

Bug Description
Title: Automatic rating/feedback prompt triggers inside fork (sub)agents and
blocks them

Summary
The automatic in-session rating prompt (the numeric "rate this response" UI) was
triggered inside a running fork agent. Because the fork has no interactive user
attached, the prompt cannot be answered and the agent becomes stuck — effectively
halted until the parent intervenes.

Repro

1. From a parent session, dispatch a fork via the Agent tool (with

CLAUDE_CODE_FORK_SUBAGENT=1) — isolation: "worktree" in my case.

1. Let the fork run a non-trivial multi-step task (substantial tool use, file

edits, test runs).

1. At some point during the fork's run, the rating UI surfaces inside the fork's

loop.

Observed

• The fork's progress halts at the rating prompt.
• The parent has no way to dismiss/answer it on the fork's behalf.
• The work the fork had in flight is suspended; the worktree is left in an

intermediate state.

Expected
Fork / subagent runs should be exempt from the automatic rating prompt entirely.
Forks are background, non-interactive workers — any UI that requires user input
from inside them will deadlock them. The rating system should only trigger on the
foreground/parent session that the user is actively interacting with.

Impact

• Breaks fan-out workflows (parallel forks) — any of the forks can lock up

unpredictably.

• Loses progress / wastes tokens already spent in the fork's context.
• Makes long-running orchestration patterns (worktree-isolated parallel forks,

federation patterns) unreliable.

Suggested fix
Gate the rating prompt on "is the active loop the top-level user-attached
session?" — when the loop is a subagent / fork (detectable via the same mechanism
that injects the no-recursion directive), suppress the prompt unconditionally.

Env

• Claude Code (Opus 4.7)
• macOS (Darwin 25.5.0)
• CLAUDE_CODE_FORK_SUBAGENT=1
• Fork dispatched with isolation: "worktree"

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.163
• Feedback ID: e9979b27-ed61-4504-80ef-f75c9af4e019

Errors

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