The send write was fixed, but the message that send echoes back arrives with
model metadata and no effort, and its model matches the one the send just
saved. That is exactly when `shouldPreserveManualModelOverride` declines to
protect the selection, so the history branch ran with no variant and recorded
"no choice" over the user's explicit `Default`. Picking Default, sending, then
switching agent and back still put the settings default in the picker.
A message carrying no effort is not evidence that the session has none. The
history branch now keeps whatever the session already recorded when the message
carries no variant, and a concrete historical effort still replaces it.
The behavior test ran the real guard through a mock that returned a fixed
answer, so the failing branch had no coverage. It now calls the real function
unless a test opts out, and the new case fails without this change.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZuVVgziiLjD81W5vaxdH2
