diff --git a/docs/test-audit-2026-09.md b/docs/test-audit-2026-09.md
new file mode 100644
index 000000000..cbac82ef6
--- /dev/null
+++ b/docs/test-audit-2026-09.md
@@ -0,0 +1,23 @@
+# Test audit 2026-09: evidence
+
+Evidence for the test-reduction branch (plan approved via /autoplan). Sections are added by the commit they support.
+
+## B8 pre-spend estimate (recorded 2026-09-29, before any B8 paid run)
+
+Source: latest weekly periodic artifacts (runs 36385945043 = 09-28, 35567915613 = 09-21), per-shard eval JSON cost_usd.
+Price ratio from test/helpers/pricing.ts: claude-fable-5-1 (default capture, lib/eval-model.ts) $10/$50 per MTok in/out;
+claude-opus-4-7 $15/$75 (ratio 0.667 on both); claude-sonnet-4-6 $3/$15 (ratio 3.33 on both).
+
+| Files | Old pin | Weekly $ (09-28) | Est. weekly $ on default | Delta |
+|---|---|---:|---:|---:|
+| plan, design, plan-prosons, plan-format, qa-bugs, retro, office-hours-phase4 | opus-4-7 | 15.78 | 10.52 | −5.26 |
+| office-hours, office-hours-brain-writeback | sonnet-4-6 | 0.91 | 3.03 | +2.12 |
+| auq-matrix, workflow | opus-4-7 | no result in the retained artifacts | — | ≤ 0 (ratio 0.667) |
+| **B8 total** | | 16.69 | 13.55 | **−3.14** |
+
+Assumes the same token volume per case (a verbosity change moves this; the ratio applies to input and output alike).
+Wall clock: unchanged shard walls (budgets do not depend on model). Drop threshold, fixed now: B8 is dropped from this PR
+if its estimated net weekly dollars after C and B5 savings are above zero. Estimated net: −3.14 (B8) − C savings
+(five retired evals) − B5 savings (18 hollow shards, 23 census judges) < 0 → B8 proceeds to its one paid run.
+Fallback check: `git log -S claude-sonnet-4-6` on skill-e2e-office-hours and -brain-writeback shows only 636175d / #2264
+(infra hardening), no cost rationale → both re-pinned.
diff --git a/test/office-hours-attempt.test.ts b/test/office-hours-attempt.test.ts
index 6ddc3e9ff..94a25295f 100644
--- a/test/office-hours-attempt.test.ts
+++ b/test/office-hours-attempt.test.ts
@@ -1,5 +1,6 @@
 /** Free recording fixtures; every runner and judge below is synthetic. */
 import { describe, expect, spyOn, test } from 'bun:test';
+import { resolveEvalModel } from '../lib/eval-model';
 import * as fs from 'node:fs';
 import * as os from 'node:os';
 import * as path from 'node:path';
@@ -649,7 +650,8 @@ describe('Plan format actual capture and judge lifecycle', () => {
         expect(output).not.toContain('Unhandled error between tests');
         const starts = events.filter(event => event.kind === 'start');
         expect(starts.map(({ timeout, maxTurns, model }) => ({ timeout, maxTurns, model })))
-          .toEqual([1, 2].map(() => ({ timeout: 300, maxTurns: 10, model: 'claude-opus-4-7' })));
+          .toEqual([1, 2].map(() => ({ timeout: 300, maxTurns: 10,
+            model: file.includes('plan-prosons') ? 'claude-opus-4-7' : resolveEvalModel('capture') })));
         expect(events.filter(event => event.kind === 'ready').map(event => event.fixtureExists)).toEqual([true, true]);
         expect(entries).toHaveLength(2);
         expect(entries.map(entry => entry.attempt)).toEqual([1, 2]);
diff --git a/test/office-hours-writeback-env.test.ts b/test/office-hours-writeback-env.test.ts
index f1b6d8ef2..6c01aca10 100644
--- a/test/office-hours-writeback-env.test.ts
+++ b/test/office-hours-writeback-env.test.ts
@@ -61,7 +61,7 @@ console.log(JSON.stringify({ type: 'result', subtype: 'success', is_error: false
   // payload assertions. The negative case restores only the original typo.
   expect(suiteSource).toContain('env: childEnv,');
   let selectedSource = option === 'env' ? suiteSource : suiteSource.replace('env: childEnv,', 'extraEnv: childEnv,');
-  selectedSource = selectedSource.replace(/from '(\.\/helpers\/[^']+)'/g,
+  selectedSource = selectedSource.replace(/from '((?:\.\/helpers|\.\.\/lib)\/[^']+)'/g,
     (_match, spec: string) => `from ${JSON.stringify(path.resolve(ROOT, 'test', spec))}`);
   const suiteCopy = path.join(dir, 'writeback-suite.ts');
   fs.writeFileSync(suiteCopy, selectedSource);
diff --git a/test/office-posture-recording.test.ts b/test/office-posture-recording.test.ts
index 888387aa7..8527adece 100644
--- a/test/office-posture-recording.test.ts
+++ b/test/office-posture-recording.test.ts
@@ -1,4 +1,5 @@
 import { expect, test } from 'bun:test';
+import { resolveEvalModel } from '../lib/eval-model';
 import * as fs from 'node:fs';
 import * as path from 'node:path';
 import { CAPTURE_MS, CAPTURE_LONG_MS } from './helpers/eval-budgets';
@@ -26,7 +27,7 @@ async function exercise(owner: Owner, scenarios: Scenario[]) {
   } };
   const args: Record<string, any> = {
     expect, beforeAll: (fn: () => void) => setups.push(fn), afterAll: (fn: () => void) => finalizers.push(fn),
-    CAPTURE_MS, CAPTURE_LONG_MS, OFFICE_HOURS_BUN_GRACE_MS, runRecordedOfficeHoursAttempt,
+    CAPTURE_MS, CAPTURE_LONG_MS, OFFICE_HOURS_BUN_GRACE_MS, runRecordedOfficeHoursAttempt, resolveEvalModel,
     ROOT: '/source', runId: 'synthetic-posture-run', evalsEnabled: true,
     describeIfSelected: (_title: string, _names: string[], fn: () => void) => fn(),
     testConcurrentIfSelected: (name: string, fn: () => Promise<void>, timeout: number) => { expect(timeout).toBe(CAPTURE_LONG_MS + OFFICE_HOURS_BUN_GRACE_MS); callbacks.set(name, fn); },
@@ -44,7 +45,7 @@ async function exercise(owner: Owner, scenarios: Scenario[]) {
     runSkillTest: async (opts: any) => {
       index++; current = scenarios[index]!; expect(current).toBeDefined(); calls.push(opts);
       expect(opts.testName).toBe(owner); expect(opts.maxTurns).toBe(8); expect(opts.timeout).toBe(CAPTURE_MS);
-      expect(opts.model).toBe('claude-sonnet-4-6'); expect(opts.runId).toBe('synthetic-posture-run');
+      expect(opts.model).toBe(resolveEvalModel('capture')); expect(opts.runId).toBe('synthetic-posture-run');
       expect(opts.signal).toBeInstanceOf(AbortSignal);
       expect(opts.prompt).toContain('Skip any AskUserQuestion');
       const file = path.join(opts.workingDirectory, owner === owners[0] ? 'q3.md' : 'unlocks.md');
diff --git a/test/skill-e2e-auq-matrix.test.ts b/test/skill-e2e-auq-matrix.test.ts
index a6717c2ef..1fe3bcee7 100644
--- a/test/skill-e2e-auq-matrix.test.ts
+++ b/test/skill-e2e-auq-matrix.test.ts
@@ -27,6 +27,7 @@
  * Run a subset in the foreground with AUQ_MATRIX_ONLY="plan-eng-review,spec".
  */
 import { test } from 'bun:test';
+import { resolveEvalModel } from '../lib/eval-model';
 import { CAPTURE_MS } from './helpers/eval-budgets';
 import { describeE2ETier } from './helpers/e2e-gate';
 import * as fs from 'node:fs';
@@ -96,7 +97,7 @@ const MATRIX: MatrixSkill[] = [
     // controlled Opus re-run passed cleanly (7/7 format, substance 5, 160s).
     // The spec workflow's long pre-question phase needs the stronger model
     // to reach its first AskUserQuestion inside the turn budget.
-    model: 'claude-opus-4-7',
+    model: resolveEvalModel('capture'),
   },
   {
     skill: 'design-consultation',
diff --git a/test/skill-e2e-office-hours-brain-writeback.test.ts b/test/skill-e2e-office-hours-brain-writeback.test.ts
index fdeef14ee..12ec005f2 100644
--- a/test/skill-e2e-office-hours-brain-writeback.test.ts
+++ b/test/skill-e2e-office-hours-brain-writeback.test.ts
@@ -35,6 +35,7 @@
  */
 
 import { expect, beforeAll, afterAll } from 'bun:test';
+import { resolveEvalModel } from '../lib/eval-model';
 import { CAPTURE_LONG_MS } from './helpers/eval-budgets';
 import { execFileSync, spawnSync } from 'child_process';
 import {
@@ -228,7 +229,7 @@ exit 0
           collector: evalCollector,
           name: '/office-hours-brain-writeback',
           suite: 'Office Hours Brain Writeback E2E',
-          model: 'claude-sonnet-4-6',
+          model: resolveEvalModel('capture'),
           run: (signal) => runSkillTest({
             signal,
             prompt: `Read office-hours/SKILL.md for the workflow.
@@ -245,7 +246,7 @@ This is a test of the brain-writeback path. Do NOT skip the gbrain save step und
             timeout: CAPTURE_LONG_MS,
             testName: 'office-hours-brain-writeback',
             runId,
-            model: 'claude-sonnet-4-6',
+            model: resolveEvalModel('capture'),
             env: childEnv,
           }),
           validate: (result) => {
diff --git a/test/skill-e2e-office-hours.test.ts b/test/skill-e2e-office-hours.test.ts
index e98f6d5a4..b9572a5e7 100644
--- a/test/skill-e2e-office-hours.test.ts
+++ b/test/skill-e2e-office-hours.test.ts
@@ -10,6 +10,7 @@
  */
 
 import { expect, beforeAll, afterAll } from 'bun:test';
+import { resolveEvalModel } from '../lib/eval-model';
 import { CAPTURE_MS, CAPTURE_LONG_MS } from './helpers/eval-budgets';
 import { runSkillTest } from './helpers/session-runner';
 import {
@@ -70,7 +71,7 @@ describeIfSelected('Office Hours Forcing Energy E2E', ['office-hours-forcing-ene
       judgeMetadata,
       name: '/office-hours-forcing-energy',
       suite: 'Office Hours Forcing Energy E2E',
-      model: 'claude-sonnet-4-6',
+      model: resolveEvalModel('capture'),
       run: (signal) => runSkillTest({
         signal,
         prompt: `Read office-hours/SKILL.md for the workflow.
@@ -85,7 +86,7 @@ Write Q3 output — the forcing question you would ask this founder — to ${wor
         timeout: CAPTURE_MS,
         testName: 'office-hours-forcing-energy',
         runId,
-        model: 'claude-sonnet-4-6',
+        model: resolveEvalModel('capture'),
       }),
       validate: async (result, signal) => {
         logCost('/office-hours (FORCING)', result);
@@ -151,7 +152,7 @@ describeIfSelected('Office Hours Builder Wildness E2E', ['office-hours-builder-w
       judgeMetadata,
       name: '/office-hours-builder-wildness',
       suite: 'Office Hours Builder Wildness E2E',
-      model: 'claude-sonnet-4-6',
+      model: resolveEvalModel('capture'),
       run: (signal) => runSkillTest({
         signal,
         prompt: `Read office-hours/SKILL.md for the workflow.
@@ -166,7 +167,7 @@ Write your response — the three adjacent unlocks — to ${workDir}/unlocks.md.
         timeout: CAPTURE_MS,
         testName: 'office-hours-builder-wildness',
         runId,
-        model: 'claude-sonnet-4-6',
+        model: resolveEvalModel('capture'),
       }),
       validate: async (result, signal) => {
         logCost('/office-hours (BUILDER)', result);
diff --git a/test/skill-e2e-plan-format.test.ts b/test/skill-e2e-plan-format.test.ts
index 30981cf71..371365d66 100644
--- a/test/skill-e2e-plan-format.test.ts
+++ b/test/skill-e2e-plan-format.test.ts
@@ -18,6 +18,7 @@
  * accordingly.
  */
 import { describe, test, expect, beforeAll, afterAll } from 'bun:test';
+import { resolveEvalModel } from '../lib/eval-model';
 import { CAPTURE_MS } from './helpers/eval-budgets';
 import { runSkillTest } from './helpers/session-runner';
 import { runRecordedOfficeHoursAttempt, OFFICE_HOURS_BUN_GRACE_MS } from './helpers/office-hours-attempt';
@@ -128,7 +129,7 @@ describeIfSelected('Plan Format — CEO Mode Selection', ['plan-ceo-review-forma
     const judgeMetadata: Pick<EvalTestEntry, 'judge_scores' | 'judge_reasoning'> = {};
     await runRecordedOfficeHoursAttempt({
       collector: evalCollector, name: '/plan-ceo-review-format-mode', suite: 'Plan Format — CEO Mode Selection',
-      model: 'claude-opus-4-7', budgetMs: CAPTURE_MS,
+      model: resolveEvalModel('capture'), budgetMs: CAPTURE_MS,
       judgeMetadata,
       run: signal => runSkillTest({
         signal,
@@ -146,7 +147,7 @@ After writing the file, stop. Do not continue the review.`,
         timeout: CAPTURE_MS,
         testName: 'plan-ceo-review-format-mode',
         runId,
-        model: 'claude-opus-4-7',
+        model: resolveEvalModel('capture'),
       }),
       validate: async (result, signal) => {
         logCost('/plan-ceo-review format (mode)', result);
@@ -195,7 +196,7 @@ describeIfSelected('Plan Format — CEO Approach Menu', ['plan-ceo-review-format
     const judgeMetadata: Pick<EvalTestEntry, 'judge_scores' | 'judge_reasoning'> = {};
     await runRecordedOfficeHoursAttempt({
       collector: evalCollector, name: '/plan-ceo-review-format-approach', suite: 'Plan Format — CEO Approach Menu',
-      model: 'claude-opus-4-7', budgetMs: CAPTURE_MS,
+      model: resolveEvalModel('capture'), budgetMs: CAPTURE_MS,
       judgeMetadata,
       run: signal => runSkillTest({
         signal,
@@ -213,7 +214,7 @@ After writing the file, stop. Do not continue the review.`,
         timeout: CAPTURE_MS,
         testName: 'plan-ceo-review-format-approach',
         runId,
-        model: 'claude-opus-4-7',
+        model: resolveEvalModel('capture'),
       }),
       validate: async (result, signal) => {
         logCost('/plan-ceo-review format (approach)', result);
@@ -261,7 +262,7 @@ describeIfSelected('Plan Format — Eng Coverage Issue', ['plan-eng-review-forma
     const judgeMetadata: Pick<EvalTestEntry, 'judge_scores' | 'judge_reasoning'> = {};
     await runRecordedOfficeHoursAttempt({
       collector: evalCollector, name: '/plan-eng-review-format-coverage', suite: 'Plan Format — Eng Coverage Issue',
-      model: 'claude-opus-4-7', budgetMs: CAPTURE_MS,
+      model: resolveEvalModel('capture'), budgetMs: CAPTURE_MS,
       judgeMetadata,
       run: signal => runSkillTest({
         signal,
@@ -282,7 +283,7 @@ After writing the file with that ONE question, stop. Do not continue the review.
         timeout: CAPTURE_MS,
         testName: 'plan-eng-review-format-coverage',
         runId,
-        model: 'claude-opus-4-7',
+        model: resolveEvalModel('capture'),
       }),
       validate: async (result, signal) => {
         logCost('/plan-eng-review format (coverage)', result);
@@ -330,7 +331,7 @@ describeIfSelected('Plan Format — Eng Kind Issue', ['plan-eng-review-format-ki
     const judgeMetadata: Pick<EvalTestEntry, 'judge_scores' | 'judge_reasoning'> = {};
     await runRecordedOfficeHoursAttempt({
       collector: evalCollector, name: '/plan-eng-review-format-kind', suite: 'Plan Format — Eng Kind Issue',
-      model: 'claude-opus-4-7', budgetMs: CAPTURE_MS,
+      model: resolveEvalModel('capture'), budgetMs: CAPTURE_MS,
       judgeMetadata,
       run: signal => runSkillTest({
         signal,
@@ -348,7 +349,7 @@ After writing the file with that ONE question, stop. Do not continue the review.
         timeout: CAPTURE_MS,
         testName: 'plan-eng-review-format-kind',
         runId,
-        model: 'claude-opus-4-7',
+        model: resolveEvalModel('capture'),
       }),
       validate: async (result, signal) => {
         logCost('/plan-eng-review format (kind)', result);
diff --git a/test/skill-e2e-qa-bugs.test.ts b/test/skill-e2e-qa-bugs.test.ts
index 7858173d7..60024bff1 100644
--- a/test/skill-e2e-qa-bugs.test.ts
+++ b/test/skill-e2e-qa-bugs.test.ts
@@ -1,4 +1,5 @@
 import { describe, test, expect, beforeAll, afterAll } from 'bun:test';
+import { resolveEvalModel } from '../lib/eval-model';
 import { CAPTURE_MS, CAPTURE_LONG_MS } from './helpers/eval-budgets';
 import { runSkillTest } from './helpers/session-runner';
 import { outcomeJudge } from './helpers/llm-judge';
@@ -120,7 +121,7 @@ CRITICAL RULES:
       timeout: CAPTURE_MS,
       testName: `qa-${label}`,
       runId,
-      model: 'claude-opus-4-7',
+      model: resolveEvalModel('capture'),
     });
 
     logCost(`/qa ${label}`, result);
diff --git a/test/skill-e2e-retro.test.ts b/test/skill-e2e-retro.test.ts
index e13a22d16..e4109e77d 100644
--- a/test/skill-e2e-retro.test.ts
+++ b/test/skill-e2e-retro.test.ts
@@ -1,4 +1,5 @@
 import { expect, beforeAll, afterAll } from 'bun:test';
+import { resolveEvalModel } from '../lib/eval-model';
 import { CAPTURE_MS, CAPTURE_LONG_MS } from './helpers/eval-budgets';
 import { runSkillTest } from './helpers/session-runner';
 import {
@@ -202,7 +203,7 @@ Analyze the git history and produce the narrative report as described in the SKI
       timeout: CAPTURE_MS,
       testName: 'retro',
       runId,
-      model: 'claude-opus-4-7',
+      model: resolveEvalModel('capture'),
     });
 
     logCost('/retro', result);
diff --git a/test/skill-e2e-workflow.test.ts b/test/skill-e2e-workflow.test.ts
index ca9d60624..9ffc14b76 100644
--- a/test/skill-e2e-workflow.test.ts
+++ b/test/skill-e2e-workflow.test.ts
@@ -1,4 +1,5 @@
 import { describe, test, expect, beforeAll, afterAll } from 'bun:test';
+import { resolveEvalModel } from '../lib/eval-model';
 import { JUDGE_MS, CAPTURE_MS, CAPTURE_LONG_MS } from './helpers/eval-budgets';
 import { runSkillTest } from './helpers/session-runner';
 import {
@@ -16,7 +17,6 @@ import { extractSkillBody } from './helpers/skill-fixture';
 import { createCoverageAuditFixture } from './fixtures/coverage-audit-fixture';
 import { validateCoverageAudit, type CoverageFile } from './helpers/coverage-audit';
 import { runRecordedOfficeHoursAttempt, OFFICE_HOURS_BUN_GRACE_MS } from './helpers/office-hours-attempt';
-import { resolveEvalModel } from '../lib/eval-model';
 
 const evalCollector = createEvalCollector('e2e');
 
@@ -468,7 +468,7 @@ Write the full output (including the GATE verdict) to ${codexDir}/codex-output.m
       timeout: CAPTURE_MS,
       testName: 'codex-review',
       runId,
-      model: 'claude-opus-4-7',
+      model: resolveEvalModel('capture'),
     });
 
     logCost('/codex review', result);