core/generate/derivation/verify.py
Shay 6212943c5a feat(adr-0175): strengthen self-verification with a completeness clause
Self-verification strengthening (microscope-driven). The Phase 3b measurement
showed self-verification was necessary-but-not-sufficient: 9/13 self-verified
attempts were wrong. Inspecting them deterministically revealed most were
correct FIRST STEPS of multi-step problems that ignored numbers stated elsewhere.

Adds clause 5 to self_verifies: a derivation must account for every quantity the
problem states (problem quantities subset of used). Refuse-preferring: unused
quantities -> not self-verified. This catches the multi-step-incomplete attempts
the grounding/cue/unit clauses cannot (their operands ARE grounded).

Practice measurement: wrongs 9 -> 2 (4 correct / 2 wrong / 44 refused). The 2
survivors (0015, 0025) are COMPLETE but wrong due to missed WORD-quantities
('twice', 'her friends') -> the microscope points the next change at extraction.

Updated the disagreement test to use two complete derivations; added an
incomplete-refusal test. 32 tests pass; smoke green; serving untouched (sealed).
2026-05-28 15:53:11 -07:00

119 lines
4.9 KiB
Python

"""ADR-0175 Phase 3a — the self-verification gate.
The wrong=0-critical gate. A derivation **self-verifies** only when all hold:
1. **operand grounding** — every operand's value token appears in the problem
text (no invented numbers);
2. **operation-cue grounding** — every step's licensing cue lexeme appears in the
text (the operation is licensed by present evidence, not assumed);
3. **unit consistency** — add/subtract require a shared unit; multiply/divide may
compose across units onto the primary;
4. **no divide-by-zero**.
Grounding reuses the canonical primitives from :mod:`generate.math_roundtrip`
(single source of truth — the same checks the round-trip filter uses), so this
gate cannot drift from the round-trip contract.
``select_self_verified`` adds the cross-derivation **uniqueness** rule: among the
self-verifying derivations, a single distinct answer resolves; zero or several
refuse (the disagreement rule — preserves wrong=0).
Invariant #2: a derivation that fails any clause does not self-verify *even if its
value coincides with the gold answer* (the ``20/5 == 4`` class).
"""
from __future__ import annotations
from dataclasses import dataclass
from typing import Final
# Canonical grounding primitives — reused so this gate stays identical to the
# round-trip filter's notion of "appears in the problem text".
from generate.math_roundtrip import _token_in, _tokens, _value_grounds
from generate.derivation.extract import extract_quantities
from generate.derivation.model import GroundedDerivation
_SAME_UNIT_REQUIRED: Final[frozenset[str]] = frozenset({"add", "subtract"})
@dataclass(frozen=True, slots=True)
class SelfVerification:
verified: bool
reasons: tuple[str, ...] # empty iff verified; named failures otherwise
@dataclass(frozen=True, slots=True)
class Resolution:
answer: float
answer_unit: str
derivation: GroundedDerivation
def self_verifies(derivation: GroundedDerivation, problem_text: str) -> SelfVerification:
"""Decide whether ``derivation`` self-verifies against ``problem_text``."""
tokens = _tokens(problem_text)
reasons: list[str] = []
# 1. operand grounding — every value must be sourced from the text.
operands = [derivation.start, *(s.operand for s in derivation.steps)]
for q in operands:
if not _value_grounds(q.source_token, tokens):
reasons.append(f"operand {q.source_token!r} not grounded in text")
# 2. operation-cue grounding — every op licensed by a present lexeme.
for step in derivation.steps:
if not _token_in(step.cue, tokens):
reasons.append(f"operation cue {step.cue!r} not grounded in text")
# 3. unit consistency.
primary_unit = derivation.start.unit
for step in derivation.steps:
if step.op in _SAME_UNIT_REQUIRED and step.operand.unit != primary_unit:
reasons.append(
f"unit mismatch: {step.op} of {step.operand.unit!r} into {primary_unit!r}"
)
# 4. divide-by-zero.
for step in derivation.steps:
if step.op == "divide" and step.operand.value == 0:
reasons.append("division by zero")
# 5. completeness — a trustworthy derivation must account for every quantity
# the problem states. A derivation that ignores given numbers is an
# incomplete reading (typically a correct *first step* of a multi-step
# problem, mistaken for the whole answer). Refuse-preferring: unused
# quantities -> not self-verified. This is the clause the practice-lane
# microscope identified (ADR-0175 self-verification strengthening): it
# catches the multi-step-incomplete attempts the cue/grounding clauses
# cannot, because their operands ARE grounded.
problem_quantities = {q.source_token for q in extract_quantities(problem_text)}
used = {derivation.start.source_token}
used.update(step.operand.source_token for step in derivation.steps)
unused = problem_quantities - used
if unused:
reasons.append(f"incomplete: unused problem quantities {sorted(unused)}")
return SelfVerification(verified=not reasons, reasons=tuple(reasons))
def select_self_verified(
derivations: list[GroundedDerivation],
problem_text: str,
) -> Resolution | None:
"""Among the self-verifying derivations, return the unique answer or refuse.
Refuse-preferring: ``None`` when zero self-verify (no grounded derivation) or
when the self-verifying ones disagree (the multi-branch disagreement rule).
"""
verified = [d for d in derivations if self_verifies(d, problem_text).verified]
if not verified:
return None
distinct = {round(d.answer, 9) for d in verified}
if len(distinct) != 1:
return None # disagreement -> refuse (wrong=0)
chosen = verified[0]
return Resolution(
answer=chosen.answer,
answer_unit=chosen.answer_unit,
derivation=chosen,
)