Function suppress_unsupported_effort 

pub fn suppress_unsupported_effort(
    body: &mut Value,
    ctx: &ModelContext,
    decision: &mut SamplingDecision,
) -> Option<SuppressedEffort>

Remove a resolved reasoning_effort the observed template cannot read, and return what was removed.

Returns None — leaving body and decision untouched — for every model that is not a positive “this template does not read it”: unresolved contexts, never-observed models, unreadable caps, caps that omit the field, and templates that do read it. Also None when the ladder resolved no effort at all, which is the ordinary case: nothing was going to be sent, so nothing is suppressed and there is nothing to report.

On a suppression it does three things, and the second and third are the point:

1. deletes the top-level key from body;
2. clears decision.resolved.reasoning_effort, because that field is documented as the values written into the body and this one no longer is;
3. rewrites decision.sources.reasoning_effort to ParamSource::SuppressedByTemplate, so every provenance surface reports the suppression instead of naming the rung whose value did not survive.