Bottom-Mask Provenance Q2 Decision

Review date: 2026-04-08.

Current Status

This Q2 gate is superseded for the v0.6.x fault/semantic mask set and the schema-v2 ONNX bundle contract. fault_mask, semantic_bottom_mask, and bottom_provenance are now stable strict-inference result attributes and schema-v2 ONNX outputs. This memo remains the historical record of the Q2 keep-experimental decision; its criteria are not retroactively re-applied to that promotion.

Historical Q2 Decision

At the 2026-04-08 Q2 review, the decision was to keep the provenance path experimental for the contract that existed at that time. The review left provenance-bearing outputs and schema sidecars outside the stable public contract, while retaining the opt-in diagnostics for further evidence gathering.

That historical decision does not describe the current schema-v2 contract for the v0.6.x fault/semantic mask set. The stable Python unpacking prefix remains (decoded, bottom_mask, gap_mask), while schema-v2 ONNX bundles expose fault_mask, semantic_bottom_mask, and bottom_provenance through the stable stable_provenance_outputs schema.

Review Against The Published Gate

  • Stable-contract non-regression: satisfied for the historical review. The default eager and bundle contract at that time was still (decoded, bottom_mask, gap_mask), and the experimental path remained opt-in.
  • Downstream value threshold: not demonstrated. The repository now computes a per-run robotics provenance_routing_materiality summary, but it still does not contain the recorded Q2 review artifact plus rerun required by the promotion gate, and the roadmap benchmark-evidence item is still marked long-experiment.
  • Operational cost: acceptable for the historical experiment. That path kept ONNX outputs stable and limited the richer provenance contract to eager diagnostics plus metadata sidecars.
  • Repeatability: not demonstrated. Without the required review artifact plus rerun, promotion would be based on incomplete evidence rather than the documented gate.

Historical Rationale

At the time of the Q2 review, the diagnostics were behind explicit opt-in config, stable consumers did not depend on them, and monitoring/routing/reporting helpers consumed the signal opportunistically when present. That made the experimental path cheap to retain while the project gathered stronger benchmark evidence.

Disposition

  • Treat the 2026-04-08 keep-experimental decision as historical context, not as the current contract for fault/semantic provenance.
  • Use schema-v2 stable_provenance_outputs for current fault/semantic provenance bundle outputs.
  • Keep structural validity-factor provenance separate from the promoted fault/semantic mask set until it clears its own gate.
  • Continue to let monitoring, calibration, routing, and validation-report helpers consume provenance only when it is present.
  • Keep deprecated experimental_inference_output_schema metadata only as a compatibility alias for already-recorded experimental bundles.