Desktop app Code tab: effort picker changes never reach the running session (model receives max every turn)

Environment: Claude desktop app, Code tab, Windows 11 Pro 10.0.26200, model claude-fable-5-1, auto permission mode.

Steps:

1. Start a Code tab session.
2. During the session, change the effort picker: Extra -> High -> Low (each followed by a new user turn).

Actual: on every subsequent turn the model still receives a reasoning_effort marker of max. The picker label and the value delivered to the session disagree, and no change to the picker has any effect for the life of the session.

Expected: the selected effort applies from the next turn, as the picker implies.

Notes:

• The picker showed Extra when the session already reported receiving max, so the mismatch may exist from session start, not only after a change.
• The session-management tool set_session_effort refuses to change the current session by design, so there is no in-session workaround.
• Impact: turns run at maximum effort regardless of the setting, making small tasks very slow.