The pipeline
Birth data → Time zone normalization (IANA TZDB) → Location coordinates (WGS 84 / EPSG:4326) → Swiss Ephemeris calculation → Structured chart payload → Chart-locked AI prompt → Reading with cited placements and aspects → User follow-up questions (still locked)
How a reading is made, and how to check one
- The chart is calculated first. Positions, houses and aspects come from the ephemeris before any text exists. The language model does no astronomy.
- The text is written afterwards, from the calculated values. The model receives the chart as structured data: each body with its sign, degree and house, and each aspect with its orb.
- Each statement names the position it comes from: the body, its sign and degree, the aspect and its orb. “Venus square Saturn, orb 1.4°” can be looked up in your chart; “you value stability” on its own cannot.
What the product does not do: it does not write from a sun sign, it gives the model nothing from outside the calculated chart, and it instructs the model not to name a position the chart does not contain. An instruction lowers the risk of a made-up factor and does not remove it, which is why the positions are named. If a statement in a reading names no position, or names one your chart does not have, tell us: that is a defect, and we want to see it.
What gets locked
The chart payload sent to the language model includes, but is not limited to:
- Planet longitudes for the Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.
- Lunar nodes (True Node), Chiron, Lilith, and the four major asteroids (Ceres, Pallas, Juno, Vesta).
- Special points: Ascendant, Midheaven, Vertex, Part of Fortune.
- Twelve Placidus house cusps.
- The five major aspects between the bodies, each with its orb and whether it is applying or separating.
- For synastry: the aspects between the two charts and where each person’s planets fall in the other’s houses.
- For transits / Solar Return / electional: the relevant time window and the active aspects against the natal chart.
- Six-sphere scores (Identity, Love, Body, Money, Home, Mind), derived from the chart factors above.
What is forbidden in the model output
- Mentioning a placement that is not in the payload.
- Asserting an aspect that is not formed (within orb).
- Forecasting specific events as inevitable.
- Substituting for medical, legal or financial advice.
What the model is encouraged to do
- Cite the specific placement or aspect when making a claim.
- Describe symbolic themes in plain, everyday language, not astrology jargon.
- Surface tensions and trade-offs (squares, oppositions) as neutral patterns, not problems.
- Frame readings as reflective tools, returning choice to the user.
- Acknowledge uncertainty when birth time is unknown (the Ascendant, the Midheaven and the houses are undetermined).
Frequently asked questions
What is Chart-Locked AI Reading?
Chart-Locked AI Reading is NatalChart.AI's branded method for AI astrology readings. The language model receives the user's pre-calculated chart as structured data (planet placements, house positions, aspects with orbs, transits, sphere scores) and is instructed to explain the factors that appear in that data. Each statement names the placement it comes from, so it can be checked against the chart.
Why is locking necessary?
Language models trained on text can produce confident-sounding output without verifying it against any underlying data source. In astrology that means making up placements or aspects. Giving the model a structured chart payload, and instructing it to refuse claims that are not in the payload, is designed to reduce made-up placements while still allowing symbolic interpretation. As with any AI workflow, the interpretation should be treated as reflective rather than guaranteed.
Is this the same as Chart-Grounded AI Astrology?
Chart-Grounded AI Astrology is the broader concept: any AI reading anchored in calculated chart data. Chart-Locked AI Reading is the specific NatalChart.AI implementation: how the chart payload is shaped, what the prompt constraints are, and how the model is asked to cite its sources within the chart.
Can the AI ever talk about my chart in general terms?
Yes. The lock is on placements and aspects (factual claims about the chart), not on metaphor. The AI can explore symbolic meaning, life themes and reflective questions; it is instructed not to assert a placement or aspect that is not in the payload. That instruction lowers the risk of an invented factor but does not remove it, so a cited placement is worth checking against the calculated chart.