Methodology change notice — minimum-observation rule for GAP-H100 spot (decision)

Notice date: 2026-08-16 (UTC; all dates in this notice are UTC) Class: methodology change (publication rule). Not a correction — no published value is restated. Instrument: gap_h100_spot (GAP-H100 spot; Class 3 indicator since notice 2026-08-14 §2) Decision: the rule proposed in 2026-08-14-gap-minimum-observation-proposal.md is adopted unmodified (founder ruling 2026-08-16). Notice period: five business days, 2026-08-17 → 2026-08-21. Effective: the rule binds from the 2026-08-22 print — the same date the GAP-H100-R1Y and GTS-1Y suspensions bind (notice 2026-08-14 §1). Prints through 2026-08-21 continue under the current method with the provenance stamp and indicator class disclosing the condition. Build: follows the notice period. Nothing in the print path changes with this notice; the disclosure of the pending change rides with the series from publication (§4).

1. The rule, as adopted

The daily GAP-H100 spot print is withheld — not published — when either condition holds at print time:

1. Panel floor — fewer than two contributing providers on the day (the Baltic Asia-variant publication floor adopted in spec Part C4); or
2. All-static panel — every contributing provider is static by the unchanged-days measure computed daily in gap_h100_panel_health(): each contributor's price unchanged for ≥ STALE_PROVIDER_DAYS (7) consecutive days.

Wording, thresholds and measures are the proposal's; no modification.

2. Withheld-day representation (the proposal's deferred choice — decided)

A withheld day is a disclosed WITHHELD entry, never a silent gap. Every calendar day in the series' record from 2026-08-22 carries either a value or a dated, reasoned withholding. The entry carries the same provenance stamp a published print would carry — panel size, contributing providers with each provider's unchanged-days, transaction count, data tier, judgment applied — plus withheld: true and the reason (panel-below-two / all-static). Surfaces (the briefing, /instruments §Ⅰ, /api/print, MCP) render it as "WITHHELD — <reason>" with the stamp, in the position the value would occupy; no surface carries forward the previous value, and no chart interpolates across it.

Storage — founder ruling 2026-08-16 (settled for the 08-22 build): a SIBLING RECORD, not a constraint drop. derived_series.value stays NOT NULL — a row in the series table always carries a printed number; weakening that invariant to represent absence is the wrong direction. Withheld days live in an additive withheld_prints table (migration via the runner): series_id, date, reason, provenance (the full stamp), notice_ref — one row per withheld (series, day). It is surfaced everywhere a value would appear: the briefing, /instruments, and /api/print's continuity block, which already renders a gap with an explanation. Series continuity is then read across the two tables: every calendar day from 2026-08-22 has either a derived_series value or a withheld_prints row.

3. Notice period, and the deviation it represents

Five business days against the specification's three-month negligible-impact guidance (Part D3 §5), on the same reasoning as notice 2026-08-14 §4: no contract, derivative or forward-claims ledger entry references the series (re-verified 2026-08-16: zero forward_claims rows score against gap_h100_spot) and The Grid has zero external subscribers. The rule only withholds prints that would otherwise carry disclosed-defective information (a one-contributor level, or a panel of frozen anchors); holding those in print for three months would prioritise procedure over honesty. Publish-before-effect (ADR-003 §2) is preserved: this notice precedes the first withheld print by a full notice period.

4. Disclosure from publication

From this notice the gap_h100_spot series disclosure (both runtimes' derived-series registries, /instruments, /api/print, MCP) names the adopted rule and its effective date. Values are unchanged; the disclosure adds information.

5. What this would have done on the record (from the proposal, restated)

Applied to the 20 v3 prints to 2026-08-13: the four single-provider days (2026-08-02, 08-03, 08-05, 08-12) would have been WITHHELD — panel below two contributors — instead of printing $2.69 levels; those days account for three of the six composition-driven transitions in the variance decomposition. The all-static condition has not triggered on a two-provider day. Published history is not revised: those prints stand as published on their day's method.

6. Build scope (after 2026-08-21)

• scripts/compute_gap_print.py: withholding path — evaluate the two conditions from gap_h100_panel_health(), write the withheld_prints row with the stamp and the notice reference; derived_series receives no row for that day (its NOT NULL invariant stands); the generation-level gate refuses to write a value on a day a withholding was recorded.
• Migration: additive withheld_prints (series_id, date, reason, provenance JSONB, notice_ref; UNIQUE (series_id, date); grants per the migrations pattern) via the runner. No change to derived_series.
• Surfaces: briefing index strip, /instruments §Ⅰ chart + table, /api/print (status: "withheld" with withheld: {reason, provenance, notice_ref} beside the existing printed / not_printed / suspended; the continuity block lists the withheld day with its reason), MCP tool response, editorial prompt input.
• Tests: rule fires on the four historical single-provider fixtures; all-static fixture; two-moving-contributor day prints; no surface renders a carried-forward value.
• Downstream: Grid Basis and GCCX divergence read gap_h100_spot — on a withheld day they carry the withholding, not a stale GAP leg (build-stage decision recorded then).

7. Record

• Proposal: 2026-08-14-gap-minimum-observation-proposal.md (status → DECIDED, this notice).
• Ruling (representation): founder, 2026-08-16 — "the WITHHELD representation is a SIBLING RECORD, not a constraint drop. derived_series.value stays NOT NULL … an additive withheld_prints table via the runner — series_id, date, reason, provenance (the full stamp), notice_ref — surfaced everywhere a value would appear … Do not build tonight."
• Ruling: founder, 2026-08-16 — "adopt the minimum-observation rule as proposed … unmodified. Publish the decision notice with a five-business-day implementation period … Withheld-day representation … a disclosed WITHHELD entry carrying the provenance stamp, never a silent gap. Build follows the notice period."
• Companion: 2026-08-14-instrument-actions.md (§2 reclassification, §3 provenance stamp, §7 reinstatement path — the rule is the second half of GAP's path back to assessment class).