Shay e6439bb70f feat(adr-0250): instrument routes Tier-2 + ADR-0250 (Proposed) — arc closure

Instrument: the arithmetic-chain domain now routes each real GSM8K dev case to
Tier-1 (single-accumulator) or Tier-2 (multi-register / summation) and compares
the corridor to a symbolic fold of the SAME compiled program. Recorded coverage
moves 26/50 -> 50/50, 0 refused, PARITY (wrong=0) — the measurement catching up
to the capability. Scope note corrected (full holdout closed; remaining frontier
= derived-operand transfers + non-affine kinds + >5-atom deduction, all 0 on this
holdout). Updated the ADR-0249 instrument test pins (26->50, refused 24->0).

ADR-0250 (Status Proposed, no self-Accept; §10 ruling awaits Shay) + acceptance
evidence: multi-register model, relative conservation, atomicity, certified
summation, chain-of-custody, and the full-holdout 50/50 wrong=0 result.

10/10 instrument pins green.

[Verification]: uv run python -m pytest tests/test_adr_0249_arithmetic_lift.py tests/test_generalized_lift_instrument.py -q

2026-07-18 14:43:40 -07:00

2.9 KiB

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ADR-0250 — Acceptance Evidence

Status: Evidence pack for Shay's ruling (no self-Accept) Date: 2026-07-18 ADR: docs/adr/ADR-0250-tier2-multi-entity-arithmetic.md Design record: docs/research/tier2-multi-entity-arithmetic-spike-2026-07-18.md

Tier-2 extends the reader→Hamiltonian compiler (ADR-0249) to multi-entity arithmetic. With it, the corridor solves the entire real GSM8K dev holdout. Built in smoke-gated phases, each merged under its own PR off forgejo/main.

Phases merged

Phase	PR	Merge commit	What landed
Design spike	#71	`97b2f8b7`	multi-register model, atomicity, chain-of-custody design; probe of the 24 refused cases
T2a executor	#72	`efd5335e`	`evals/multi_register_program.py` — multi-register + transfers + conservation; 18/18 single-entity
2b summation	#73	`3c3dcdbe`	certified summation turn + `operand_source_digest`; full holdout 50/50
Instrument + ADR	this PR	—	`arithmetic-chain` domain routes Tier-2; ADR-0250 + this evidence

Smoke (uv run core test --suite smoke -q) green at every phase (176 passed).

Load-bearing result

Real GSM8K dev holdout (sealed, 50 cases):

Tier	Cases	Corridor
Tier-1 single-accumulator (ADR-0249)	26	correct, wrong=0
T2a single-entity multi-register	18	correct, wrong=0
2b certified summation ("altogether")	6	correct, wrong=0
Total	50 / 50	wrong = 0

Corridor vs symbolic fold of the same compiled program: PARITY (delta 0) — the field matches arithmetic, it does not beat it. The instrument's arithmetic-chain domain now records 50/50 coverage, 0 refused.

Verified in-tree

Transfer conservation + per-register exactness: Ruth 36→31, Sara 19→24, sum conserved; 200 random transfers exact + conserving to ~6e-11.
Relative conservation pin: gma-050 (chains to 222) tripped an absolute 1e-6 tolerance; the relative check |Δ| ≤ rtol·max(1,|before|) fixes it and still catches real violations.
Chain of custody: summation records carry operand_source_digest; tamper on any non-terminal record breaks the successor link (verify_multi_register_chain).

Design decisions applied (honest register)

Atomicity via immutability: prepare→validate→commit; no partial-mutation window, no rollback.
Summation stays in the substrate (ruling #1): each addition is a certified turn, never a Python sum(); the total is grounded in RelaxationCertificates.
The summation signal is the typed unknown.entity is None, not an inferred op pattern.

What remains open (not claimed here)

Derived-operand transfers ("half of X") — designed + guarded, 0 on this holdout.
Non-affine kinds (rate/comparison/fraction/partition) — 0 on this holdout, refused.
5-atom deduction via ROBDD-partitioned turn programs — future arc.
ADR-0246 §3.7 admission-policy calibration — unchanged; no gate activated.

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