logicsrc/docs/openontology-interoperability.md

OpenOntology interoperability

How OpenOntology relates to JSON Schema, JSON-LD, RDF, SHACL, PROV-O, and external identifier systems — and, just as importantly, where the mappings stop. Companion to OpenOntology.

The guiding rule: report what a format cannot carry; never drop it silently.

Where each format sits

Format	Role
JSON Schema 2020-12	Canonical, normative contract. The schemas are the standard.
Canonical JSON	Deterministic bytes for hashing, signing, diffing, publishing.
YAML	Human authoring convenience. Compiles to canonical JSON.
NDJSON	Streaming format for large entity/claim/source files.
JSON-LD 1.1	Interoperability profile for the semantic-web world.
RDF / Turtle	Planned export of the losslessly mappable subset.
SHACL	Planned mapping for the constraint subset with equivalent semantics.
PROV-O	Vocabulary reused for provenance where the semantics genuinely match.

OpenOntology does not require RDF, OWL, SPARQL, or a triple store. It maps to them so that consumers who need formal reasoning can get there.

JSON-LD

logicsrc ontology export --dir ./ethereum-ecosystem --format jsonld --out graph.jsonld

Entities become nodes. Claims are reified — each claim is its own node with subject, predicate, object, status, time, confidence, and provenance — because the provenance is the point. A bare triple cannot say "asserted by this agent, from this commit, valid since April, confidence 0.94."

Provenance terms alias PROV-O rather than inventing parallel vocabulary:

OpenOntology	JSON-LD term
assertedAt	prov:generatedAtTime
assertedBy	prov:wasAttributedTo
sources	prov:wasDerivedFrom
runId	prov:wasGeneratedBy
confidence	oo:confidence (xsd:double)
validTime.from / .to	oo:validFrom / oo:validTo
status	oo:status

Compact ids canonicalize to IRIs against the package namespace; the Namespace object binds the prefix, which is what makes the reverse direction unambiguous. The round trip JSON → JSON-LD → JSON preserves ids, types, subjects, predicates, objects, typed values, language tags, statuses, times, confidence, sources, evidence, and supersession links.

Lossy fields

The 0.1 JSON-LD profile does not carry: tags, license, visibility, retention, changeSet, model, firstParty, derivedFrom, retractionReason, and extensions. Export reports them per object:

warning: 3 object(s) have fields this format cannot carry:
  eth:claim:0042: tags, license

The same holds in the other direction: importing a foreign vocabulary that expresses semantics the core model lacks reports the gap instead of quietly discarding it.

External identifiers

An entity carries namespaced external ids without treating any external service as the identity authority:

externalIds:
  github: averyl
  wikidata: Q000000
  orcid: 0000-0000-0000-0000
  did: "did:example:abc"

Lookup works by exact id, canonical name, alias, or external id. findEntities returns ranked candidates with the evidence for each match — never a silent single answer.

sameAs is a reviewable claim, not an implicit merge. Two records only become one through an approved merge-entity operation, and the losing id survives as a redirect.

RDF and Turtle

logicsrc ontology export --dir ./ethereum-ecosystem --format turtle --out graph.ttl

Claims are reified, exactly as in JSON-LD, and an asserted relationship claim additionally emits the plain triple — so a consumer that only wants the current accepted graph gets one without unpacking provenance.

Import parses the profile this exporter produces rather than pretending to be a general Turtle parser. Anything it cannot interpret is listed in unsupported, never dropped silently.

SHACL

logicsrc ontology export --dir ./ethereum-ecosystem --format shacl --out shapes.ttl

Five constraint kinds map onto SHACL Core: required-predicate, cardinality, allowed-values, domain-range, and temporal-bounds. Severity carries across (error → sh:Violation, warning → sh:Warning).

Two do not, and are reported as unmapped in the returned value and as comments in the generated Turtle:

• unique — graph-wide uniqueness has no portable SHACL Core equivalent; it needs a sh:SPARQLConstraint.
• query — an OpenOntology saved query is a triple-pattern AST, not SPARQL.

A shape that silently means something narrower than the constraint it came from is worse than no shape, so those stay unmapped until the mapping is real.

OWL/RDFS

Still planned. An optional mapping for consumers needing formal reasoning. OpenOntology itself infers nothing: transitivity, symmetry, and inverses apply only when the schema declares them and a query asks.

Compatibility matrix

Target	0.1 status	Notes
JSON Schema 2020-12	supported	Canonical contract; 16 object kinds
Canonical JSON + digest	supported	Deterministic across Node.js and Bun
YAML authoring	supported	Same digest as equivalent JSON
NDJSON	supported	Streaming entity/claim/source/evidence files
JSON-LD 1.1 export	supported	Reified claims, PROV-O aliases, lossy report
JSON-LD 1.1 import	supported	Round-trips the reference profile
PROV-O	partial	Provenance terms aliased in JSON-LD and Turtle; full mapping later
RDF / Turtle export	supported	Reified claims + plain triples for asserted relationships
RDF / Turtle import	supported	Round-trips the reference profile; reports what it cannot read
SHACL	partial	5 of 7 constraint kinds; unique and query reported as unmapped
OWL / RDFS	planned	Optional, for external reasoners
SPARQL	planned	Query AST → SPARQL adapter
Cypher	planned	Query AST → Cypher adapter
Datalog	planned	Query AST → Datalog adapter
SQLite / Turso	supported	createLibsqlStore, versioned migrations, FTS5 entity search
REST + OpenAPI	supported	16 paths, described at /api/ontologies/openapi
Server-Sent Events	supported	Same event objects as the JSON endpoint
MCP	supported	Resources, tools, and prompts; writes propose, never apply
Neo4j / vector DBs	not required	Optional adapters; never mandatory

Query portability

The triple-pattern AST is deliberately small so a second implementation is achievable. Adapters translate it to SQL, SPARQL, Cypher, or Datalog and must report their capabilities — an adapter that cannot do multi-hop traversal or asOf says so rather than returning a subtly wrong answer.

Aggregation, grouping, faceting, and path-finding are P1: useful, but not in the 0.1 evaluator, so that the portable core stays implementable.

Embeddings

Optional, rebuildable, provider-neutral derived data. They may improve discovery; they are never the sole representation of a fact and never authoritative. A package with its embeddings deleted loses nothing canonical.

Importing

Imports propose; they never apply:

logicsrc ontology import --file graph.jsonld --dir ./my-ecosystem

{ "entities": 63, "claims": 169, "proposedOperations": 12 }

The result is a set of operations for a change set. Source adapters must declare whether they can read public data, private data, incremental changes, and deletions, and what licence the source carries. An ingestion run is repeatable from its declared sources, mappings, parser version, and model configuration.

Deduplication runs on stable id, external id, exact alias, normalized URL, and reviewed similarity candidates — with the last of those always going to a human.