Evidence mechanisms for Content Telemetry claims.
This repository holds the SPUR evidence profile: an optional profile layered on the Content Telemetry standard that defines how telemetry claims can be corroborated. It is a working draft; nothing here is normative yet.
Core telemetry events are claims by identified emitters (SCOPE.md in the standard). Core deliberately answers only the first of its five conformance questions - syntactic validity. This profile takes up the next three: cryptographic validity, trust-policy acceptance, and factual truth and completeness. Entitlement as a legal conclusion belongs to governing terms and is out of scope here as it is in core.
Version 1.0 of the standard carries the hooks this profile uses, and nothing more:
- Events are claims; no field raises its own evidentiary status (standard, sections 5.2.3 and 6.8, SCOPE.md)
content_fingerprinton grounding events:scheme,detected,value, detection only (section 6.4)- The generic evidence slot on content events:
scheme, detachedref,digest(section 6.8) - Manifest signing keys (section 8.4) and the
Content-Telemetry-IDretrieval correlation (section 7.2)
The profile pins the core version it targets and cannot redefine core event semantics.
One profile, four modules. Each module states the bounded proposition its evidence supports. The boundary rule binds all of them: access evidence never becomes proof of grounding, and cryptographic validity never becomes factual truth, completeness, or entitlement.
| Module | Proposition supported | Origin | Editors |
|---|---|---|---|
| Fingerprint schemes | A declared scheme's signal was checked in an identified representation | Standard issues #5, #16, #17; PR #21 | [TBC] |
| VPTS seeded observations | A publisher-seeded marker was observed in reported or sampled output | Standard issue #18 | [TBC] |
| Recomputable attribution | A disclosed attribution result recomputes from disclosed inputs | Standard issues #19, #20 | [TBC] |
| Entitlement credentials | A signed, unrevoked grant from an identified issuer covered the reported access | Standard issue #22; PR #34 | [TBC] |
Module maturity is described as workflow levels V0-V3 within the profile; the levels describe how far a module's tooling and fixtures have progressed, not a ladder of assertion strength.
The recomputable-attribution module also specifies the attribution report shape its recomputation check runs over. That carrier travels as a namespaced extension in the standard's data container, which profiles may define (SCOPE.md in the standard); listing it as a known extension in the core repository is a separate step, taken once two independent estimators exchange the same shape (standard issue #19).
The working group is chartered in CHARTER.md. Contribution does not require SPUR membership: file issues here, and propose new capabilities as short human-written notes per CONTRIBUTING.md. Decisions are recorded publicly on this tracker.
Apache License 2.0. See LICENSE.