Follow one value from origin bytes to typed result

The chain ●Implemented

One field — the currency of an offer — from the bytes an origin returned to the typed value an agent receives. The origin said usd. The agent is told USD. Everything between those two facts is recorded, and can be recomputed without the origin being online.

1. Originhttp://127.0.0.1:18080/product/sku-001 returned 162 bytes of application/json with status 200, under policy tw.fetch.local-fixture-v0.
2. EvidenceThose bytes are stored and retrieved by their digest: sha256:e194e7dfd8bad2e92564e2a01527aad79af467feda26733d9d06ac2132ebd73a
3. ObservationRetrieval metadata is bound to that digest in a canonical CBOR envelope, itself addressed as sha256:98025ae34cf1c21ea7bf14c9ca0e2a25f504a9ec1768ec6c0f5202ac49d02e57
4. VerificationTwo independent implementations validate the envelope and re-hash the body: Go, and a restricted C verifier with no network path.
5. Adapterorigin:testorigin/product-offer version 0.1.0, admitted by hand, digest sha256:86995ebf29b33eb6e23e871de86fdc4112bba3d5101b21781e9f750482c03117
6. Native statementAt locator /offer/currency the provider's own term origin:testorigin/currency holds the lexical value usd.
7. Declared transformationtrim then uppercase — ASCII only, by decision, and recorded rather than applied silently.
8. Semantic interpretationcommerce:OfferPrice.currency under closure sha256:9ef146c90f8c4e252ef47aa5df0adfb8f17d3d88d67c671502886ce1c58427f4, relation equivalent_in_context.
9. Typed resultType currency_code, value USD, carrying the whole chain above it. Result digest sha256:b00b1d5832548a27c5244ef7315876ef9bf6898310bfe582365a3900b8ebbbe5

Field by field

The five fields the Gate E1 demonstration resolves. Each one carries its own native statement, semantic interpretation, and complete derivation record.

Raw representation

The exact bytes the controlled origin returned, read from the content-addressed store by the digest the observation records. A controlled local fixture origin, not a production source. Loopback access is denied unless explicitly enabled.

{"availability":"in_stock","name":"Field Notebook","offer":{"currency":"usd","current_price":"19.99"},"product_id":"sku-001","updated_at":"2026-08-10T00:00:00Z"}

This is a fixture, deliberately. The point of E1 is not that this document is interesting; it is that the path from these bytes to a typed value is complete and checkable.

Observation

The canonical envelope binds retrieval metadata to the evidence digest. Its field order and byte bounds are normative, defined in CDDL, and enforced identically by both implementations.

Independent verification

A single implementation cannot tell you whether a rule belongs to the protocol or only to the code that happens to enforce it. Two can.

The adapter digest above is not taken on trust either: the build recomputes the SHA-256 of adapters/testorigin-product/adapter.json↗ and fails if it differs from the digest every field's provenance cites.

Unresolved is a result, not a gap

An optional field that the origin did not provide becomes an explicit unresolved result with provenance, and no fabricated lexical value.

Vector missing-optional-source-field uses this source, which simply has no availability member:

{
  "name": "Missing optional availability",
  "offer": {
    "currency": "usd",
    "current_price": "19.99"
  },
  "product_id": "sku-missing-optional"
}

A resolved empty string stays distinct from unresolved: see the resolved-empty-string vector. And a required field that cannot be extracted does not degrade — it fails closed, and no result is published at all.

Conformance vectors

The 11 committed extraction vectors. Six of them exist to prove that the system refuses input, which is the half of conformance that is easy to skip.

The chip marks the expected outcome, not a pass or fail: accept means the system must produce a result; reject means it must refuse. All eleven behaved as expected in the E1 run. There are a further 16 shared observation vectors, run identically in Go and C.

Sources of this page

The generator records the digest of every artefact it read, so a reviewer can check that the published proof came from the bytes they can see in the repository.

Regenerate with make demo at the repository root, then cd web && go run . -evidence. Full evidence record on the proof page; the report itself is reports/gate-1-genesis.md↗.