A child should inherits the current session’s model, context tier, and reasoning effort unless explicitly overridden.

この issue には説明がありません。

The issue body names no files, tests, or entry points. Start by locating child-session creation and the current session's model, context tier, and reasoning-effort settings, then inspect existing tests for inheritance and explicit overrides. Done means child sessions inherit each setting unless that setting is explicitly overridden.

索引モデルが issue の本文から書いたものです。