Add Corpus T signal-age decay axis v2_a12 for stale search items

filter rejected AXIS reversible: simple 4h proposed 30 May 2026

What is the proposed change?

Add v2_a12 (signal_freshness, 0-3) keyed off Corpus T evidence age. For each proposal, look up the youngest source_corpus='T' evidence row. Score: 3 = ≤14d old, 2 = 15-45d, 1 = 46-120d, 0 = >120d or no T evidence at all. Insert into filter_score.js composite. Persist the youngest-T timestamp per proposal in audit. Distinct from existing axes because none currently penalize stale external-signal grounding; the engine has no temporal awareness of when search results were collected.

Target files

hypothesis_engine/moves/filter_score.js hypothesis_engine/corpora/transcripts.js

Expected effect

Proposals grounded only in stale Corpus T (e.g. older SerpAPI sweeps from S91-S104) score ≥1 lower than proposals grounded in current week's digest entries. On a 30-day backtest, composite-score correlation with Commander 'still relevant' subjective tag should improve by ≥0.15 Pearson.

Falsifier — what would prove this wrong?

If Commander's keep/kill decisions over 30 days show no correlation (|r| < 0.1) with v2_a12 score, freshness isn't a load-bearing signal for this engine and the axis is decoration — remove it.

Evidence that triggered the proposal

T — digest entries span 2026-05-18 through 2026-05-29 (12-day rolling window already present)
D — brain/DESIGN_PRINCIPLES.md P85 (write-time vs query-time memory — freshness is a query-time concern)
E — kill_reason_distribution: 7× v2_backfill_orphan_S148 (S148 = stale session anchor still triggering kills)

Proposer self-score

The proposer scored its own draft on these axes (0-3 each) before submitting.

Axis	Score
specificity	3
falsifier	2
solo feasible	3
blast radius	1
composability	3
reversibility	3

Disposition

Rejected by filter_score. The proposal did not meet the bar for specificity, falsifiability, or solo-feasibility.

Evaluation history

When	Move
2026-05-30 04:06	meta_filter_score
2026-05-30 04:03	meta_genesis