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Open Trust Format and Claim Package Shape

Status: Surface compatibility guide; Hachure is normative

The Open Trust Format is Hachure, whose

hachure.org/v1 schemas, derivation and merge semantics, assurance rules, and

conformance vectors are normative. This document describes Surface's

compatibility commitment: Surface constructs, validates, derives, re-exports,

and presents Hachure-compatible trust state while keeping it exportable,

embeddable, locally inspectable, and usable without a proprietary hosted

service. If this guide and the Hachure specification disagree, Hachure wins and

Surface must reconcile the integration.

Claim Package

A Claim Package is the portable unit a producer emits or exports so Surface tools can evaluate, display, or share product transparency state.

A minimum Claim Package contains:

  • schemaVersion
  • producer identity
  • claims
  • evidence
  • verification policies
  • verification events
  • optional claim groups
  • optional identity links
  • optional materiality mappings
  • optional evidence traces
  • optional authority traces
  • optional integrity references
  • optional producer extension reference
  • optional transparency capabilities

In the current implementation, this shape is represented primarily through TrustBundle and generated into TrustReport. Product language may call the evaluated projection a Trust Snapshot.

Core Records

Claims describe what a producer says is true enough to inspect. Evidence supports or challenges claims. Policies describe what evidence, methods, authority, freshness, and conflict behavior matter. Events record append-only claim lifecycle changes.

Evidence uses claimId as the compatibility link to its claim. Consumers that only need the single-hop graph can continue reading claimId. Consumers that evaluate whether a claim is supported should also read evidence.supportStrength: omitted means entails for legacy packages, entails means the evidence can satisfy policy support, and cited means reference/context evidence that remains visible but is insufficient to verify the claim by itself.

Trace and integrity records explain how evidence or authority was produced, who or what produced it, when it was observed, and what source state it was anchored to. Hachure standardizes the portable core representation; Surface owns its product-facing integration and extensions. Producers own claim-group and verification workflows.

For Survey-produced source-of-authority observations, producer-declared source authority belongs under Evidence.metadata.sourceAuthority. It is evidence metadata unless the producer can emit a producer-neutral actor or system authority record.

Authority Trace

Authority Trace is the portable authority context for evidence, attestations, and claims. The current field name is authorityTrace, available on both TrustBundle and TrustReport.

Reserve authorityTrace for portable actor or system authority. Do not use it as a bucket for Survey source-authority declarations that only describe how the producer interpreted a source.

Each Authority Trace record contains:

  • id
  • subject
  • actorRef
  • authorityType: role, permission, credential, system, organization, policy, or other
  • authorityRef
  • sourceRef
  • observedAt
  • optional evidenceIds and claimIds
  • optional validFrom, validUntil, revokedAt, integrityRef, and metadata

Example:

{
  "id": "authority.record-steward-1",
  "subject": { "subjectType": "record", "subjectId": "record-1" },
  "actorRef": "actor:record-steward-1",
  "authorityType": "role",
  "authorityRef": "role:record-steward",
  "sourceRef": "directory:records-team",
  "observedAt": "2026-05-01T00:04:00.000Z",
  "evidenceIds": ["evidence.record.attestation"],
  "claimIds": ["claim.record.status"],
  "validUntil": "2026-12-31T00:00:00.000Z",
  "integrityRef": "sha256:directory-entry"
}

Authority Trace is not a Surface-owned authorization engine. Producers own authentication, permission checks, credential verification, revocation checks, and signatures. Surface validates and preserves the generic record, then projects active, expired, and revoked authority state for consumers.

Required Properties

A package emitted or consumed through Surface must preserve these portability

properties in addition to the normative Hachure requirements:

  • deterministic: same input produces the same derived trust state
  • inspectable: humans and agents can see claims, evidence, freshness, and gaps
  • portable: no hosted Surface dependency is required to parse it
  • explicit: missing, private, redacted, permissioned, unavailable, and stale evidence remain distinguishable
  • extensible at the edge: producer-specific fields belong in extension or metadata areas unless the concept is portable

Current Implementation Names

Use current field names only where exact technical reference requires them:

  • TrustBundle is the current claim package input contract.
  • TrustReport is the current derived report contract.
  • schemaVersion: 2 and schemaVersion: 3 remain accepted.
  • evidence.execution remains the current structured execution trace field.
  • evidence.supportStrength distinguishes cited/reference support from entailing support; omitted means entailing for legacy claimId evidence.
  • authorityTrace remains the current structured authority trace field.
  • metadata remains valid for producer-specific trace details until first-class portable fields are added.
  • transparencyGaps remains the current typed gap field; product docs should present it as Transparency Gaps or Conflicts.
  • claimGroups remains the current grouping field; product docs should present it as Claim Groups.

Non-Goals

  • no proprietary handshake requirement
  • no global identity provider requirement
  • no Surface-owned evidence collection
  • no universal legal, compliance, or action verdict