ChartID — space.chartid.*

An open AT Protocol Lexicon for astrological charts as self-sovereign identity records.

Steward domain: chartid.space
Lexicon namespace: space.chartid
Status: RFC / Pre-release — open for comment

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What this is

Every AT Protocol user has a DID. Their astrological chart - if they want one — should live in their own repo, portable across the entire Atmosphere, not locked inside any single app.

space.chartid.* defines the data model. No app owns the records. No app owns the standard.

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Protocol architecture

Records live in user repos

A natal chart record at space.chartid.natalChart in a user's repo is:

• Signed by their repo key
• Readable by any Atmosphere app with Lexicon support
• Deletable by the user at any time
• Not migrated when they switch PDS — it's their data

A record looks like:

{
  "$type": "space.chartid.natalChart",
  "schemaVersion": "1.0.0",
  "traditions": ["western", "jyotish"],
  "birthDatetime": "1990-04-15T14:32:00Z",
  "birthPlace": {
    "placeName": "Oakland, CA, USA",
    "coordinate": { "latitude": "37.804363", "longitude": "-122.271111" },
    "timezone": "America/Los_Angeles"
  },
  "timeConfidence": "exact",
  "roddenRating": "AA",
  "western": { ... },
  "jyotish": { ... },
  "createdAt": "2025-01-01T00:00:00Z"
}

DID-level identity

subjectDID optionally links the chart to an AT identity. A person can point their own DID to their own chart — or keep them separate. Consent is explicit, not assumed.

attestedBy is an array of astrologer DIDs. Multiple practitioners can attest to chart accuracy without creating a separate attestation service. Each attesting DID is expected to publish a corresponding attestation record of their own.

Multi-tradition by design

traditions is an array. A single record can carry both Western tropical and Jyotish sidereal data:

{
  "traditions": ["western", "jyotish"],
  "western": { "houseSystem": "Placidus", "planets": [...] },
  "jyotish": { "ayanamsa": "Lahiri", "ayanamsaDegrees": "24.112300", "planets": [...], "vargaCharts": [...] }
}

Apps that only understand one tradition ignore the other. The record serves both without forking.

Unknown birth times are valid records

birthDatetime is optional. timeConfidence signals the reliability of the time:

• exact — birth certificate / hospital record
• approximate — family memory, close estimate
• unknown — date known, time not
• rectified — time derived by rectification (see rectificationNote)

A chart with timeConfidence: "unknown" is a valid, useful partial record — rising sign and houses are absent, planets are present.

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Lexicon files

File	Description
space.chartid.defs	Shared types: bodyPosition, houseCusp, westernData, jyotishData, vargaChart, dashaTree, etc.
space.chartid.natalChart	Birth chart. key: "tid" — users can hold multiple (Western, Jyotish, rectified versions).
space.chartid.eventChart	Moment in time: eclipses, launches, IPOs. eventDatetime required.
space.chartid.entityChart	Organization, country, institution. entityName required.
space.chartid.horaryChart	Horary / Prashna: a sincere question at a moment. questionDatetime required.
space.chartid.electionalChart	Elected / Muhurta: chosen auspicious timing. electionalDatetime required.

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Design decisions

No floats in ATProto Lexicon. All degree values are decimal degree strings ("254.378500"). Explicit, lossless, no float precision surprises.

schemaVersion: "1.0.0" is a const field. Breaking schema changes will bump to 2.0.0 with a new lexicon file, not in-place mutation. Old records stay valid under old readers.

extensions: unknown at top level and within each tradition block. Tradition-specific fields not yet in spec go here without breaking existing record validation. This is how Hellenistic lots, Uranian midpoints, and shadbala scores get added incrementally.

traditions is an array, not an enum. One record, multiple simultaneous traditions. Compare western and Jyotish placements in a single query.

houseSystem and ayanamsa are explicit fields, never inferred from context or packed into a planet position string. A chart without a declared house system is ambiguous. These fields make it unambiguous.

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Adoption

Implementing this Lexicon

1. Declare space.chartid.natalChart as a supported collection in your PDS config
2. Point to lexicons/ in this repo for schema validation
3. Write records via com.atproto.repo.createRecord with collection: "space.chartid.natalChart"

Live site

chartid.space — protocol overview, demo space.chartid.natalChart record rendered as a North Indian Jyotish chart, full Lexicon namespace listing. Hosted on Cloudflare Pages from this repo (index.html).

Implementations

jyotish-mcp — reference calculator. Swiss Ephemeris, TypeScript, Lahiri ayanamsa. Produces ChartID-format Jyotish output. Vimshottari dasha calculation.

Artiji — first consumer app writing space.chartid.natalChart records. Astrological greeting card platform; chart data generated at card creation, written to user ATProto repo on consent.

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RFC

Open discussion: bluesky-social/atproto Discussions

Feedback on: namespace choice, field naming, extension model, multi-tradition record vs separate records per tradition.

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Contributing

See CONTRIBUTING.md.

Schema changes follow semantic versioning:

• Patch: clarifications, description improvements
• Minor: new optional fields, new knownValues entries
• Major: required field additions, type changes, field removals

All changes via PR with rationale. Breaking changes require RFC comment period before merge.

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License

Lexicon definitions: CC0 — no rights reserved. Use freely.