Good, and boringly so, which is what you want from a school. The village has its own primary carrying its parish name. The nearest secondary sits a short drive away. Almost eight in ten graded settings across the county come out good or better. Nobody moves to Cornwall for the education and then finds themselves apologising for it.
Ofsted has graded 120 settings across Cornwall, and 95 of those hold good or outstanding, which is close to four in five. Three are rated outstanding, 20 require improvement and five are rated inadequate. A further 113 settings hold no published grade at all, either because they have not been inspected or because their inspection type carries no overall effectiveness judgement, and they belong in neither column. These are county-wide numbers rather than village ones, which matters in a place this size: Polgooth does not have enough schools to generate a statistic of its own, so the honest frame is the authority it sits inside.
The important caveat is the one every parent learns the hard way. Naming a school near a house is not the same as securing a place at it. Cornwall allocates on its own admissions rules, oversubscription changes year to year, and the offer letter arrives in spring regardless of what the estate agent implied in October. Check the current admissions position with the council before you let a school shape which house you buy.
For primary, St Mewan Community Primary School is the one carrying the parish name and the obvious first look for a family here. Beyond it the local cluster includes St Stephen Churchtown Academy, Whitemoor Academy and Sky Primary and Eden Project Nursery, which is the one that will make you look twice at the name. The rest of the surrounding primaries are a scatter of village and small-town schools across the St Austell area, each serving its own patch, most of them the sort of two-form-entry place where the head knows every child by name and every parent by car.
Secondary is simpler, in the way that rural secondary usually is: Brannel School is the one in range, and that is the answer rather than a shortlist. In practice this means the secondary decision is made for you by geography, and the daily reality is a bus or a lift rather than a walk. Families here should assume driving is part of the school run, because almost everything about getting around this village already assumes it.
The schools are one of the real strengths of living here, and the reason is dullness in the best sense: the county-wide picture is solid, the local primary is straightforward to find, and the secondary question answers itself. What you should spend your worry on is admissions timing, not quality.