SPECIFICATION · AXIA.SIGNALS.V0 · EXPERIMENTAL

Axia Signals

Experimental, probabilistic observations about content. Strictly separated from Axia Verify. Signals are never cryptographic evidence.

This profile is Experimental.

Signals are probabilistic observations, not definitive conclusions. They MUST NOT be presented as cryptographic verification, as moderation decisions, or as adjudication of authenticity. Verifiers MAY surface signals as informational context, with explicit "experimental" labelling.

1. Scope

Axia Signals (axia.signals.v0) is an analytical layer that produces observational signals about content. It is intentionally separated, at the architectural, semantic and commercial levels, from Axia Verify (axia.trust.v1).

Verify produces evidence. Signals produces observations. The two MUST NOT be combined into a single boolean or trust score by the protocol.

2. Separation rules

Implementations MUST respect the following invariants:

• Signal observations MUST be stored in a separate ledger from trust_events. The reference implementation uses signal_observations.
• A signal MUST NOT declare evidence_class = "cryptographic" or "attested".
• A signal MUST NOT declare evidence_strength = "strong".
• A signal MUST carry a confidence in [0, 1] and a detector_version.
• A signal MUST carry a signal_scope in { content, metadata, network, identity, behavioral }.
• A signal SHOULD declare a detector_family and a reproducible flag for auditability.
• confidence and severity are independent dimensions and MUST NOT be collapsed into a single score.
• Public verification surfaces MUST NOT render signals as authoritative. Default visibility is org-only.
• UI MUST NOT use language such as "AI-generated", "fake", "real" or "trusted" when rendering signals. Probabilistic wording is required.
• UI MUST NOT render confidence as a percentage. Use qualitative bands (low / medium / high) with explicit "observational" qualifiers.

3. Output schema

signal_observation (axia.signals.v0)

3a. Confidence vs severity

Confidence expresses how strongly the detector believes the observation. Severity expresses how critical the observation is for the consumer. They are independent.

• A signal MAY have high confidence and low severity (e.g. confirmed minor metadata anomaly).
• A signal MAY have low confidence and high severity (e.g. potential identity revocation match).
• Verifiers MUST NOT derive a single "trust score" from confidence × severity.

3b. Signal scopes

Every signal declares the surface it observed:

• content — the payload itself (pixels, bytes, audio).
• metadata — container, EXIF, encoder chain, declared disclosures.
• network — distribution, propagation, replay patterns.
• identity — signing identity lifecycle, revocations, rotations.
• behavioral — operational behaviour around the content over time.

4. Signal catalog

missing_provenance

No cryptographic provenance, signing identity or publisher disclosure was found.

metadata_inconsistency

Container metadata (EXIF, timestamps, encoder chain) shows inconsistencies that warrant review.

synthetic_artifact_indicator

Statistical artifacts compatible with synthetic generation pipelines were observed. Probabilistic only.

disclosure_inconsistency

Publisher-attested disclosure conflicts with observational signals (e.g. declared human_created with synthetic indicators).

continuity_anomaly

Lifecycle continuity exhibits anomalies (rapid mass propagation, repeated continuity breaks, replay patterns).

identity_recently_revoked

Content was attributed to an identity that has been recently revoked or rotated.

5. Lifecycle

Signals are ephemeral: they MAY expire and MAY be recomputed by improved detector versions. They are NOT append-only evidence.

Detectors SHOULD publish their detector_version with each observation so that historical signals can be reproduced or invalidated.

6. Non-goals

• Signals are not an "AI detector". The protocol does not adjudicate whether content was generated by AI.
• Signals do not produce moderation, ranking or takedown decisions.
• Signals do not modify, shadow or downgrade Axia Verify evidence.

7. Machine-readable registry

The current signal catalog is published at /protocol/registry/signals.json.