Function knob_edit_prompt 

pub(crate) fn knob_edit_prompt(
    metric_name: &str,
    goal: &str,
    goal_description: Option<&str>,
    best_value: Option<f64>,
    history: &[RoundRecord],
    attempt_memory: Option<&str>,
    last_verdict_json: &str,
    crate_diff: &str,
    note: Option<&str>,
    plan: Option<&str>,
    inventory: &str,
) -> String

Knob-phase coder prompt. With a planner plan (openai backend) it just asks the coder to apply that one-line default change. Without a plan (subprocess backends, which have no separate planner) it carries the round context plus the knob inventory so the coder can pick and apply a knob itself.