# BRIEF-11D — Next-Capability Proposal (post GSM8K reader closure) **Status:** Proposed (decision artifact) **Date:** 2026-05-27 **Author:** Shay **Anchor:** [[thesis-decoding-not-generating]] **Parent brief:** [BRIEF-11](../handoff/BRIEF-11-phase-2-reader-closure-and-capability-snapshot.md) **Gating rule:** [ADR-0166 — Measurement-Capability Sequencing Discipline](./ADR-0166-measurement-capability-sequencing.md) --- ## Purpose Pick the single next capability to land after the Phase 2 reader closure pass (Brief 11B-step-2 + 11C snapshot). One choice. Defended. Three rejected with reasons. Per Brief 11 §"lead engineer has a yes/no decision artifact, not another sprawling roadmap." ADR-0166's three-question test gates every candidate: - **Q1** What capability does this build before measurement? - **Q2** What existing lane validates it? (No new lanes.) - **Q3** What invariant proves `wrong=0` / closure / determinism? --- ## Candidates ### Candidate A — Continued GSM8K operator closure Extend the comprehension reader (ADR-0164) for the remaining bottleneck classes from `audit_brief_11.md`: `multi_quantity_composition` (8), `quantity_extraction` (9), `fraction_percentage_literal` (3), `comparatives`, rate parsing. Mechanical, per-frame work in `generate/comprehension/`. - **Q1 — Capability**: Each frame is a new composition rule on the existing `ComprehensionState` machine. The reader, state shape, and lexicon pack already exist on main; this is operator-level extension. - **Q2 — Lane**: `evals/gsm8k_math/train_sample/v1` (canonical, in place). Capability-axis G1–G5, S1 lanes act as the regression net. - **Q3 — Invariant**: `wrong == 0` by construction (admissibility + unit-proof + multi-branch-disagreement refusal stay in force). Determinism: frozen-dataclass state + canonical-bytes serialization → byte-equal trace hash on rerun. Closure: bottleneck audit row count strictly decreases. ### Candidate B — Cross-domain reader generalization Port the incremental comprehension reader pattern to a non-math domain (e.g. `en_core_relations_v1` kinship statements or `en_core_cognition_v1` belief statements) to prove the architecture isn't math-overfit. Authors a sibling lexicon pack and a parallel state machine. - **Q1 — Capability**: A second reader instance, sharing the `ComprehensionState` abstraction but with a domain lexicon + frame rules. Reader machinery is generic; domain coupling is the test. - **Q2 — Lane**: Existing `evals/identity_divergence/` and the cognition-axis lanes consume relations/cognition packs today. No new lane required. - **Q3 — Invariant**: Same admissibility + refusal contract as the math reader; pack-level mastery report + manifest checksum + byte-equal trace hash. **But:** the math reader has not yet cleared its first capability gate (GSM8K Round-2 exit `correct ≥ 25`). ADR-0166 §"Forbidden work" — measurement of a generalization before the original capability is anchored produces noise, not signal. ### Candidate C — Tool-use trace integration Let the engine invoke deterministic tools (calculator, unit canonicalizer, ratified-pack lookup) within a turn and record the invocation in the trace. Hardens the teaching corridor by giving contemplation a deterministic compute primitive. - **Q1 — Capability**: A typed `ToolCall` record on the turn trace, whitelisted to deterministic pure-function tools (no network, no filesystem, no LLM), with replay-equivalence guarantees. - **Q2 — Lane**: None of the existing canonical lanes exercise tool-use. `evals/long_context_cost/` and capability-axis lanes measure end-to-end accuracy, not intermediate compute. Adding a lane would violate ADR-0166. Existing teaching-corridor tests (`evals/identity_divergence/`, `evals/cognition/`) do not branch on tool presence — so they cannot distinguish capability-present from capability-absent. - **Q3 — Invariant**: `wrong == 0` extends only if every tool is pure and deterministic. Determinism: tool output canonicalized into trace hash. Closure: undefined — the set of useful tools is open-ended. ### Candidate D — Workbench demo hardening Make the read-only operator UI (ADR-0160/0162) load-bearing for HITL ratification (ADR-0161), replay theater (W-031), and proposal queue (W-029). Moves the workbench from demo-tier to operator-tier infrastructure. - **Q1 — Capability**: Surface-level integration of already-shipped backend mechanisms (ratification queue, contemplation candidates, replay). No new operator, no new recognizer, no new composition rule. - **Q2 — Lane**: Workbench has no canonical capability lane in Tier 3 or capability-axis tables; it is operator-facing infra, not a measured capability. ADR-0166 §"Boundaries" — the rule governs eval lanes; UI work is out of scope for this ADR but also out of scope for Brief 11's "next capability" question. - **Q3 — Invariant**: Determinism inherited from the underlying ratification + replay paths. `wrong == 0` not directly applicable — workbench is an inspector, not an admitter. Closure: W-029/W-031 acceptance criteria, not capability closure. --- ## Recommendation **Recommended next: Candidate A — Continued GSM8K operator closure.** ### Why it beats the others on lift-per-risk 1. **Three-question test passes cleanly.** Capability exists (reader scaffolding on main); lane exists (`gsm8k_math/train_sample/v1` with a real baseline at 3/47/0 today, the Phase 2 closure baseline after 11B-step-2); the invariant is mechanical (`wrong == 0` by construction + determinism by frozen state). 2. **The bottleneck audit names the work.** `audit_brief_11.md` has already ranked the highest-leverage missing operators (`lexicon_entry: 9`, `multi_quantity_composition: 8`, `quantity_extraction: 9`). The backlog is queued, sized, and risk-categorized. 3. **It is the only candidate that converges.** Phase 2 reader closure has an explicit exit criterion (ADR-0163 Round-3 `correct ≥ 35`, `wrong = 0`). The work has a finish line. Candidates B, C, D do not — each opens new surface area. 4. **It unblocks every other candidate.** ADR-0166 §"Forbidden work" rejects authoring lanes/generalizations ahead of the capability that produces signal. Math reader closure is the gate every other candidate inherits. ### Rejection rationale - **B (cross-domain reader)** — Generalizing the reader before the math reader clears Round-2 (`correct ≥ 25`) measures a generalization of an unanchored capability. The cross-domain result would be uninterpretable: a refusal could mean either the pattern doesn't generalize *or* the underlying reader is still under-built. Defer until math reader clears Round-3. - **C (tool-use trace integration)** — Fails Q2 (no existing lane distinguishes tool-present from tool-absent) and Q3 (closure is undefined). The mechanism is conceptually clean but ADR-0166 forbids building a capability whose signal would require a new lane to register. Revisit once a math problem class demonstrably refuses for reasons a calculator would resolve — that grounds the tool surface in real data. - **D (workbench demo hardening)** — UI work is not a capability in the ADR-0166 sense. It does not advance `listen → comprehend → recall → think → articulate → learn`. It hardens a viewing surface for mechanisms that already work. Worth doing when the operator workflow demands it; not the next *capability* commit. ### First sub-PR scope **Branch:** `feat/brief-12a-lexicon-entry-closure` **Target:** `audit_brief_11.md` row `lexicon_entry: 9` (lowest-risk, highest-count, cannot create wrong admissions without also passing graph-completeness — per audit §"Highest-leverage backlog"). Deliverables (single PR): - 9 lexicon entries added to `en_core_math_v1` with a manifest checksum bump and deterministic ordering. - Pack test pinning the 9 new lemmas + their semantic categories. - Reader rerun on `train_sample/v1` showing the 9 cases move from `unknown_word` either to admitted (preferred) or to a different refusal class (acceptable — surfaces the next gap). - `wrong == 0` preserved. Exit: `correct` rises by some amount ≥ 0, and the `unknown_word` row in the audit taxonomy strictly decreases. Refusal taxonomy may grow at other rows — that is real new work becoming visible, not regression. ### Dependencies - **Blocked on:** Brief 11B-step-2 (the two in-flight closure-fix branches) merging to main. The audit artifact and reader scaffolding must be the version 11D operates against. - **Blocked on:** Brief 11C (capability snapshot) producing the post-closure baseline. The first 11D sub-PR's delta is measured against that baseline, not the pre-closure 3/47/0. - **Independent of:** Workbench work (Candidate D), tool-use scoping (Candidate C), and any cross-domain reader prototype (Candidate B). Those remain backlog. --- ## Definition of "decided" This document is a decision artifact, not a roadmap. The decision recorded here: > The next capability after GSM8K reader Phase 2 closure is > continued GSM8K operator closure, starting with the > `lexicon_entry` row of the Brief 11B audit. No new lanes. No > cross-domain prototype. No tool-use scoping. No workbench > promotion. Revisit candidates B/C/D after the math reader > clears ADR-0163 Round-3 (`correct ≥ 35`, `wrong = 0`). Reopening this decision requires either: 1. The first 11D sub-PR fails to register signal (audit `unknown_word` row does not shrink), indicating the lexicon-entry path is not the right next step, or 2. The math reader clears Round-3 ahead of expectation, retiring Candidate A and bringing B/C/D back into scope. --- ## Cross-references - [ADR-0166](./ADR-0166-measurement-capability-sequencing.md) — the three-question test this document answers four times. - [ADR-0164](./ADR-0164-incremental-comprehension-reader.md) — the architecture this recommendation extends. - [BRIEF-11](../handoff/BRIEF-11-phase-2-reader-closure-and-capability-snapshot.md) §"Failure modes to avoid §3" — eval surface inflation; this document declines to inflate it. - `evals/gsm8k_math/train_sample/v1/audit_brief_11.md` — the bottleneck table the first sub-PR attacks. - [SESSION-2026-05-27-tier3-sequencing](./SESSION-2026-05-27-tier3-sequencing.md) — the narrative grounding for "capability before measurement, measurement before expansion."