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+# Brief 11 — Phase 2 Reader Closure and Capability Snapshot
+
+**Status:** Active handoff
+**Date:** 2026-05-27
+**Branch:** `docs/brief-11-handoff`
+**Scope:** Private repo planning and execution handoff only. No public-safe disclosure. No runtime claim is made by this document.
+
+---
+
+## Thesis
+
+Brief 11 should close the current comprehension-reader corridor before widening measurement or domain scope.
+
+The latest project state establishes three facts that must govern sequencing:
+
+1. `gsm8k_math` is not blocked by a lack of eval lanes. It is blocked by incomplete statement understanding.
+2. The ADR-0164 reader is the correct replacement path for the brittle ADR-0163 recognizer/injector surface.
+3. ADR-0166 now forbids authoring new canonical eval lanes ahead of the capability they measure.
+
+Therefore Brief 11 is not "make more benchmarks." Brief 11 is the bounded closure pass that turns the Phase 2 reader line into a reliable capability snapshot, then tells the next operator exactly what can safely happen after it.
+
+---
+
+## Current operating facts
+
+Recent PR descriptions and session logs show the corridor clearly:
+
+- Phase 1 reader coexistence is additive and flag-gated. With the flag off, behavior should remain byte-identical.
+- Phase 1 handles question sentences; statement sentences remained on the regex parser.
+- Phase 2 statement-frame work is the dominant path because most refused cases are caused by recognized-but-skipped statements / incomplete solver graphs.
+- Wrong-answer protection is currently more important than raising correct count by unsafe partial admission. The wrong=0 guard must remain non-negotiable.
+- Main has ADR-0166, which states that measurement follows capability, not the other way around.
+
+Brief 11 must preserve those facts instead of drifting back into lane proliferation or superficial UI/demo work.
+
+---
+
+## Goal
+
+Produce a mechanically useful handoff for the next engineering pass after Brief 10 / Phase 2 reader work:
+
+1. Define the closure gates for the Phase 2 statement reader.
+2. Define the capability snapshot that should be run immediately after closure.
+3. Define the no-go boundaries that prevent unsafe widening.
+4. Define the next branch/PR sequence so a lead engineer can continue without re-litigating the strategy.
+
+---
+
+## Non-goals
+
+Brief 11 does not:
+
+- add new OOD eval lanes;
+- claim expert-level GSM8K capability;
+- relax wrong=0;
+- bypass the reader with broader regex patches;
+- add public-facing disclosure material;
+- promote any audit/expert/demo tier;
+- mutate seed packs or teaching stores as a side effect of chat/runtime smoke tests.
+
+---
+
+## Acceptance gates
+
+### Gate 1 — Reader completeness delta
+
+Run the canonical GSM8K train-sample measurement with the reader path enabled and disabled.
+
+Required outputs:
+
+- baseline regex-only result;
+- reader-enabled result;
+- refused/correct/wrong counts;
+- per-case refusal reason taxonomy;
+- explicit list of cases fixed by Phase 2 statement frames;
+- explicit list of cases still refused and why.
+
+Hard invariant:
+
+- `wrong == 0` must hold.
+
+If `correct` rises while `wrong > 0`, the PR is not a success. It is a regression with useful diagnostics.
+
+### Gate 2 — Recognized-skipped statement audit
+
+For every still-refused case where the reader recognized tokens but did not inject a complete graph, emit a compact audit row:
+
+```text
+case_id | sentence_index | recognized_terms | skipped_frame | missing_operator | refusal_reason
+```
+
+This is the main Brief 11 artifact because it turns the remaining GSM8K bottleneck into queued capability work instead of guesswork.
+
+### Gate 3 — Graph completeness proof
+
+For every admitted case, prove the solver graph is complete before candidate projection:
+
+- all quantities have owners or intentionally anonymous scope;
+- all units are canonicalized;
+- operations are typed;
+- question target slot resolves to an entity/unit/kind;
+- no recognized-but-uncommitted frame is present.
+
+This gate is the successor to the wrong=0 guard. The guard catches unsafe admission; graph completeness prevents unsafe admission from being attempted.
+
+### Gate 4 — Determinism and trace stability
+
+Run the reader-enabled measurement twice with identical input and config.
+
+Required:
+
+- identical case outcomes;
+- identical trace hashes where applicable;
+- stable refusal taxonomy ordering;
+- no nondeterministic iteration over entity registries, frame sets, or lexicon categories.
+
+### Gate 5 — Feature-flag hygiene
+
+The reader path must remain explicitly controlled until the capability snapshot justifies default-on behavior.
+
+Required:
+
+- flag-off path remains byte-compatible with current main expectations;
+- flag-on path produces trace evidence that reader code actually executed;
+- fallback behavior is explicit: reader refusal may fall through only when doing so cannot hide a recognized-skipped statement.
+
+### Gate 6 — Capability snapshot, not promotion
+
+After the above gates pass, run the existing relevant lanes / tables to populate the current capability snapshot.
+
+Allowed:
+
+- rerun existing GSM8K / capability-axis lanes;
+- update current metric artifacts;
+- populate existing TBD rows only where the lane already exists and produces signal.
+
+Forbidden:
+
+- adding new canonical lanes just to make the table look complete;
+- treating a snapshot as expert promotion;
+- merging a measurement PR that conceals capability absence behind aggregate numbers.
+
+---
+
+## Recommended branch / PR sequence
+
+### PR 11A — Reader Phase 2 closure audit
+
+**Branch:** `feat/brief-11-reader-closure-audit`
+
+Deliverables:
+
+- audit artifact for recognized-skipped statement cases;
+- per-case refusal taxonomy;
+- graph-completeness assertion helpers;
+- tests around incomplete graph refusal.
+
+Exit condition:
+
+- measurement identifies the exact remaining missing operators without raising `wrong`.
+
+### PR 11B — Reader closure fixes
+
+**Branch:** `feat/brief-11-reader-closure-fixes`
+
+Deliverables:
+
+- minimal statement-frame fixes for the highest-leverage missing operators;
+- no broad regex expansion unless proven temporary and fenced;
+- deterministic tests for each newly admitted case;
+- updated measurement artifact.
+
+Exit condition:
+
+- correct count improves or refusal taxonomy shrinks, while `wrong == 0`.
+
+### PR 11C — Existing-lane capability snapshot
+
+**Branch:** `eval/brief-11-capability-snapshot`
+
+Deliverables:
+
+- rerun existing relevant lanes only;
+- update metric ledgers / result JSONs;
+- summarize what changed after the reader closure;
+- explicitly list deferred lanes that remain blocked by missing capability.
+
+Exit condition:
+
+- snapshot numbers are reproducible and do not claim promotion.
+
+### PR 11D — Next capability proposal
+
+**Branch:** `docs/brief-11-next-capability-proposal`
+
+Deliverables:
+
+- a concise proposal selecting the next capability after GSM8K reader closure;
+- must pass ADR-0166's three-question test before any new lane is authored;
+- should compare: continued GSM8K operator closure, cross-domain reader generalization, tool-use trace integration, and Workbench demo hardening.
+
+Exit condition:
+
+- lead engineer has a yes/no decision artifact, not another sprawling roadmap.
+
+---
+
+## Failure modes to avoid
+
+### 1. Correct-count greed
+
+Raising correct count by allowing incomplete graph admission violates the project. Any such result should be treated as a failed experiment, not progress.
+
+### 2. Regex relapse
+
+ADR-0165 exists because regex can be useful at boundaries but dangerous as a semantic substitute. Brief 11 should not broaden regex to impersonate reader comprehension.
+
+### 3. Eval surface inflation
+
+New lanes before capability will generate uniform refusals and strategic noise. ADR-0166 forbids this.
+
+### 4. Snapshot-as-promotion
+
+A capability snapshot is a diagnostic state report. It is not an expert promotion, investor claim, or public disclosure.
+
+### 5. Hidden side effects
+
+Reader measurement must not mutate teaching stores, seed packs, runtime state, or public-facing artifacts unless the PR explicitly declares and tests those mutations.
+
+---
+
+## Minimum evidence package for the final Brief 11 PR
+
+The final PR in this sequence should include:
+
+```text
+- command(s) run
+- environment/config flags
+- baseline result path
+- reader-enabled result path
+- before/after correct/refused/wrong table
+- still-refused taxonomy
+- fixed-case taxonomy
+- graph completeness assertion summary
+- determinism rerun summary
+- explicit deferred-work list
+```
+
+Suggested table:
+
+| Mode | Correct | Refused | Wrong | Notes |
+|---|---:|---:|---:|---|
+| regex-only baseline | TBD | TBD | TBD | current main behavior |
+| reader Phase 1 | TBD | TBD | TBD | question-frame reader only |
+| reader Phase 2 closure | TBD | TBD | TBD | statement-frame reader path |
+
+---
+
+## Definition of done
+
+Brief 11 is done when the repo has a reproducible, reviewed capability snapshot after Phase 2 reader closure and a precise backlog of remaining missing operators.
+
+It is not done merely because a document exists. This document is the operator handoff; the engineering sequence above is the work.
diff --git a/docs/handoffs/BRIEF-11-phase-2-reader-closure-and-capability-snapshot.md b/docs/handoffs/BRIEF-11-phase-2-reader-closure-and-capability-snapshot.md
new file mode 100644
index 00000000..dcc8eb0c
--- /dev/null
+++ b/docs/handoffs/BRIEF-11-phase-2-reader-closure-and-capability-snapshot.md
@@ -0,0 +1,292 @@
+# Brief 11 — Phase 2 Reader Closure and Capability Snapshot
+
+**Status:** Proposed handoff
+**Date:** 2026-05-27
+**Branch:** `docs/brief-11-handoff`
+**Scope:** Private repo planning and execution handoff only. No public-safe disclosure. No runtime claim is made by this document.
+
+---
+
+## Thesis
+
+Brief 11 should close the current comprehension-reader corridor before widening measurement or domain scope.
+
+The latest project state establishes three facts that must govern sequencing:
+
+1. `gsm8k_math` is not blocked by a lack of eval lanes. It is blocked by incomplete statement understanding.
+2. The ADR-0164 reader is the correct replacement path for the brittle ADR-0163 recognizer/injector surface.
+3. ADR-0166 now forbids authoring new canonical eval lanes ahead of the capability they measure.
+
+Therefore Brief 11 is not "make more benchmarks." Brief 11 is the bounded closure pass that turns the Phase 2 reader line into a reliable capability snapshot, then tells the next operator exactly what can safely happen after it.
+
+---
+
+## Current operating facts
+
+Recent PR descriptions and session logs show the corridor clearly:
+
+- Phase 1 reader coexistence is additive and flag-gated. With the flag off, behavior should remain byte-identical.
+- Phase 1 handles question sentences; statement sentences remained on the regex parser.
+- Phase 2 statement-frame work is the dominant path because most refused cases are caused by recognized-but-skipped statements / incomplete solver graphs.
+- Wrong-answer protection is currently more important than raising correct count by unsafe partial admission. The wrong=0 guard must remain non-negotiable.
+- Main has ADR-0166, which states that measurement follows capability, not the other way around.
+
+Brief 11 must preserve those facts instead of drifting back into lane proliferation or superficial UI/demo work.
+
+---
+
+## Goal
+
+Produce a mechanically useful handoff for the next engineering pass after Brief 10 / Phase 2 reader work:
+
+1. Define the closure gates for the Phase 2 statement reader.
+2. Define the capability snapshot that should be run immediately after closure.
+3. Define the no-go boundaries that prevent unsafe widening.
+4. Define the next branch/PR sequence so a lead engineer can continue without re-litigating the strategy.
+
+---
+
+## Non-goals
+
+Brief 11 does not:
+
+- add new OOD eval lanes;
+- claim expert-level GSM8K capability;
+- relax wrong=0;
+- bypass the reader with broader regex patches;
+- add public-facing disclosure material;
+- promote any audit/expert/demo tier;
+- mutate seed packs or teaching stores as a side effect of chat/runtime smoke tests.
+
+---
+
+## Acceptance gates
+
+### Gate 1 — Reader completeness delta
+
+Run the canonical GSM8K train-sample measurement with the reader path enabled and disabled.
+
+Required outputs:
+
+- baseline regex-only result;
+- reader-enabled result;
+- refused/correct/wrong counts;
+- per-case refusal reason taxonomy;
+- explicit list of cases fixed by Phase 2 statement frames;
+- explicit list of cases still refused and why.
+
+Hard invariant:
+
+- `wrong == 0` must hold.
+
+If `correct` rises while `wrong > 0`, the PR is not a success. It is a regression with useful diagnostics.
+
+### Gate 2 — Recognized-skipped statement audit
+
+For every still-refused case where the reader recognized tokens but did not inject a complete graph, emit a compact audit row:
+
+```text
+case_id | sentence_index | recognized_terms | skipped_frame | missing_operator | refusal_reason
+```
+
+This is the main Brief 11 artifact because it turns the remaining GSM8K bottleneck into queued capability work instead of guesswork.
+
+### Gate 3 — Graph completeness proof
+
+For every admitted case, prove the solver graph is complete before candidate projection:
+
+- all quantities have owners or intentionally anonymous scope;
+- all units are canonicalized;
+- operations are typed;
+- question target slot resolves to an entity/unit/kind;
+- no recognized-but-uncommitted frame is present.
+
+This gate is the successor to the wrong=0 guard. The guard catches unsafe admission; graph completeness prevents unsafe admission from being attempted.
+
+### Gate 4 — Determinism and trace stability
+
+Run the reader-enabled measurement twice with identical input and config.
+
+Required:
+
+- identical case outcomes;
+- identical trace hashes where applicable;
+- stable refusal taxonomy ordering;
+- no nondeterministic iteration over entity registries, frame sets, or lexicon categories.
+
+### Gate 5 — Feature-flag hygiene
+
+The reader path must remain explicitly controlled until the capability snapshot justifies default-on behavior.
+
+Required:
+
+- flag-off path remains byte-compatible with current main expectations;
+- flag-on path produces trace evidence that reader code actually executed;
+- fallback behavior is explicit: reader refusal may fall through only when doing so cannot hide a recognized-skipped statement.
+
+### Gate 6 — Capability snapshot, not promotion
+
+After the above gates pass, run the existing relevant lanes / tables to populate the current capability snapshot.
+
+Allowed:
+
+- rerun existing GSM8K / capability-axis lanes;
+- update current metric artifacts;
+- populate existing TBD rows only where the lane already exists and produces signal.
+
+Forbidden:
+
+- adding new canonical lanes just to make the table look complete;
+- treating a snapshot as expert promotion;
+- merging a measurement PR that conceals capability absence behind aggregate numbers.
+
+---
+
+## Recommended branch / PR sequence
+
+### PR 11A — Reader Phase 2 closure audit
+
+**Branch:** `feat/brief-11-reader-closure-audit`
+
+Deliverables:
+
+- audit artifact for recognized-skipped statement cases;
+- per-case refusal taxonomy;
+- graph-completeness assertion helpers;
+- tests around incomplete graph refusal.
+
+Exit condition:
+
+- measurement identifies the exact remaining missing operators without raising `wrong`.
+
+### PR 11B — Reader closure fixes
+
+**Branch:** `feat/brief-11-reader-closure-fixes`
+
+Deliverables:
+
+- minimal statement-frame fixes for the highest-leverage missing operators;
+- no broad regex expansion unless proven temporary and fenced;
+- deterministic tests for each newly admitted case;
+- updated measurement artifact.
+
+Exit condition:
+
+- correct count improves or refusal taxonomy shrinks, while `wrong == 0`.
+
+### PR 11C — Existing-lane capability snapshot
+
+**Branch:** `eval/brief-11-capability-snapshot`
+
+Deliverables:
+
+- rerun existing relevant lanes only;
+- update metric ledgers / result JSONs;
+- summarize what changed after the reader closure;
+- explicitly list deferred lanes that remain blocked by missing capability.
+
+Exit condition:
+
+- snapshot numbers are reproducible and do not claim promotion.
+
+### PR 11D — Next capability proposal
+
+**Branch:** `docs/brief-11-next-capability-proposal`
+
+Deliverables:
+
+- a concise proposal selecting the next capability after GSM8K reader closure;
+- must pass ADR-0166's three-question test before any new lane is authored;
+- should compare: continued GSM8K operator closure, cross-domain reader generalization, tool-use trace integration, and Workbench demo hardening.
+
+Exit condition:
+
+- lead engineer has a yes/no decision artifact, not another sprawling roadmap.
+
+---
+
+## Failure modes to avoid
+
+### 1. Correct-count greed
+
+Raising correct count by allowing incomplete graph admission violates the project. Any such result should be treated as a failed experiment, not progress.
+
+### 2. Regex relapse
+
+ADR-0165 exists because regex can be useful at boundaries but dangerous as a semantic substitute. Brief 11 should not broaden regex to impersonate reader comprehension.
+
+### 3. Eval surface inflation
+
+New lanes before capability will generate uniform refusals and strategic noise. ADR-0166 forbids this.
+
+### 4. Snapshot-as-promotion
+
+A capability snapshot is a diagnostic state report. It is not an expert promotion, investor claim, or public disclosure.
+
+### 5. Hidden side effects
+
+Reader measurement must not mutate teaching stores, seed packs, runtime state, or public-facing artifacts unless the PR explicitly declares and tests those mutations.
+
+---
+
+## Minimum evidence package for the final Brief 11 PR
+
+The final PR in this sequence should include:
+
+```text
+- command(s) run
+- environment/config flags
+- baseline result path
+- reader-enabled result path
+- before/after correct/refused/wrong table
+- still-refused taxonomy
+- fixed-case taxonomy
+- graph completeness assertion summary
+- determinism rerun summary
+- explicit deferred-work list
+```
+
+Suggested table:
+
+| Mode | Correct | Refused | Wrong | Notes |
+|---|---:|---:|---:|---|
+| regex-only baseline | TBD | TBD | TBD | current main behavior |
+| reader Phase 1 | TBD | TBD | TBD | question-frame reader only |
+| reader Phase 2 closure | TBD | TBD | TBD | statement-frame reader path |
+
+---
+
+## Definition of done
+
+Brief 11 is done when the repo has a reproducible, reviewed capability snapshot after Phase 2 reader closure and a precise backlog of remaining missing operators.
+
+It is not done merely because a document exists. This document is the operator handoff; the engineering sequence above is the work.
+
+---
+
+## Suggested PR body template
+
+```markdown
+## Summary
+
+Brief 11 handoff: closes the ADR-0164 Phase 2 reader corridor before widening measurement scope. Defines gates for reader completeness, recognized-skipped statement audit, graph completeness, determinism, feature-flag hygiene, and existing-lane snapshot.
+
+## Why
+
+Recent PRs show the GSM8K bottleneck is incomplete statement understanding, not missing eval lanes. ADR-0166 requires capability before measurement expansion.
+
+## Deliverables
+
+- docs/handoffs/BRIEF-11-phase-2-reader-closure-and-capability-snapshot.md
+
+## Test plan
+
+Docs-only. No runtime change.
+
+## Follow-up sequence
+
+- 11A: reader closure audit
+- 11B: closure fixes
+- 11C: existing-lane capability snapshot
+- 11D: next capability proposal
+```