L3 neutral drift emission and trust-layer independence#

Decision#

Lookout emits neutral, typed drift in its own vocabulary and depends on nothing in the trust layer — neither the @kontourai/surface foundation nor any product built on it (including @kontourai/survey). createDriftEmitter replaces the prior SurveyEmitter: its DriftResult carries events, facts, and a priorObservationId (null on the first-ever observation, set on every later genuine comparison), with no surveyInput field and no authored trust-bundle record of any kind.

Every ProposalEvidence still carries snapshotRef / locator / excerpt / extractor / fieldPath, so emitted events remain Hachure-evidence-shaped — they map one-to-one onto a Hachure evidence record — but that shape is a convenience for whoever consumes them, not a dependency Lookout takes on. Lifting DriftResult events into a Hachure TrustBundle is the consumer's or product's job, done with @kontourai/surface's TrustBundleBuilder. Lookout authors no claims, review outcomes, or provenance-resolution policy, and imports no type or value from @kontourai/survey or @kontourai/surface.

The rationale mirrors the L2 precedent set by Traverse's ExtractionProposal: a building block's output can be trust-format-aware in shape (so a consumer's mapping is cheap and mechanical) while remaining trust-format-independent in dependencies (so the building block itself never couples to, exact-pins, or breaks on a product's release cadence). Traverse's proposals already matched Survey's shape without importing survey; Lookout's drift events now do the same for Hachure/Surface.

The CLI command renamed from emit-survey to emit-drift accordingly, with matching option/error-message renames (emitSurvey → emitDrift), but its I/O contract — one compact JSON object per stdout line, exit codes, bounded --observation <path|-> / --observation-root reading, stderr diagnostics — is unchanged.

Boundary#

Lookout owns deterministic prior/current derivation, observation continuity, facts, and neutral event emission. Callers own proposal extraction and identity callbacks. A consumer or product owns lifting DriftResult events into a Hachure TrustBundle via @kontourai/surface's TrustBundleBuilder, and owns all review, supersession, precedence, and carry-forward policy.