A chart's validated facts as ranked, citable atoms for interpretation. Each fact has a stable id (e.g. "aspect:moon~neptune:conjunction"), the bodies it concerns, a salience score (luminaries, angular placements, the chart ruler, tight/hard aspects, configurations rank high), and a plain-language statement. Facts span placements, aspects, configurations, the structural signature, dispositors and receptions, a body's tight conjunction with a bright fixed star (e.g. "star:jupiter:Sirius"), and the Part of Fortune and Spirit (e.g. "lot:fortune"). Read the facts, write the interpretation in your own words, and cite the [id] each statement rests on — do not introduce facts not listed. Returns the ranked facts plus a ready-to-interpret `brief`.
By default a real birth chart: pass date+lat+lon. The chart's grounding is first-class via `realm` (what it is: observed/forecast/fictional/mythic/archetypal/…) and the time: an exact `date`, an uncertain `earliest`+`latest` range (the brief then frames it as provisional and trusts the Moon/angles/houses less), `constraints` for an archetypal chart with no time (synthesized via the compiler), or a full structured `when` (relative-to-another-event or a narrative calendar). A `when` of kind `relative` looks its `anchorId` up in `anchors` (a map of id → UTC instant supplied in the request). Omit lat+lon for a placeless chart (nominal houses).