feat(review): simplification specialist — advisory over-engineering lens with ponytail's tag vocabulary

New 8th Review Army specialist (DIFF_LINES > 100, --simplification force flag)
hunting unrequested STRUCTURE only: delete/stdlib/native/speculative/shrink
closed tags, one-line findings, lines_removable field. speculative: replaces
ponytail's yagni: tag — we import the lens, not the posture; coverage stays
sacred (Completeness Gaps owns it, suppressions inlined, shrink needs >=5 lines).

Advisory carve-out in the merge step: advisory findings are excluded from
quality_score and the findings-count header, render with an [ADVISORY] label,
and are ASK-only in Fix-First. Zero-findings case prints the lens-scoped
'Simplification: lean already — nothing to cut.' from the PARENT (the
specialist keeps the exact NO FINDINGS contract); with findings, the parent
prints 'net: -N lines possible' summed from lines_removable.

Tests: static pins for the carve-out + early-out contract (gen-skill-docs),
two periodic e2e cases with planted fixtures — activation (over-build traps:
hand-rolled Intl, one-impl abstract, dead config) and false-flag precision
(a lean ETHOS 'choose A' diff must yield NO FINDINGS).

Inspired by dietrichgebert/ponytail's /ponytail-review.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/fixtures/review-army-lean-complete.js

@@ -0,0 +1,28 @@
+// Lean-and-complete fixture: the false-flag precision case for the
+// simplification specialist. This is an ETHOS "choose A" diff — small,
+// covers the error path and edge cases, carries its own check. There is
+// nothing here to cut; a correct simplification pass returns NO FINDINGS.
+
+function parsePort(value) {
+  if (value === null || value === undefined || value === '') {
+    throw new Error(`parsePort: missing value`);
+  }
+  const port = Number(value);
+  if (!Number.isInteger(port) || port < 1 || port > 65535) {
+    throw new Error(`parsePort: expected integer in 1-65535, got ${JSON.stringify(value)}`);
+  }
+  return port;
+}
+
+// Self-check: the smallest thing that fails if the logic breaks.
+function testParsePort() {
+  const assert = require('node:assert');
+  assert.strictEqual(parsePort('8080'), 8080);
+  assert.strictEqual(parsePort(443), 443);
+  assert.throws(() => parsePort(''), /missing value/);
+  assert.throws(() => parsePort('0'), /1-65535/);
+  assert.throws(() => parsePort('65536'), /1-65535/);
+  assert.throws(() => parsePort('abc'), /1-65535/);
+}
+
+module.exports = { parsePort, testParsePort };

test/fixtures/review-army-overbuild.js

@@ -0,0 +1,68 @@
+// Planted over-engineering fixture for the simplification specialist.
+// Three deliberate invitations: a hand-rolled date formatter the platform
+// ships (native:), an abstract layer with exactly one implementation
+// (speculative:), and a config block nothing reads (delete:).
+
+// INVITATION 1 (native:): Intl.DateTimeFormat does all of this in one line.
+class DateFormatter {
+  constructor(locale) {
+    this.locale = locale || 'en-US';
+    this.monthNames = [
+      'January', 'February', 'March', 'April', 'May', 'June',
+      'July', 'August', 'September', 'October', 'November', 'December',
+    ];
+  }
+
+  pad(n) {
+    return n < 10 ? '0' + n : String(n);
+  }
+
+  formatLong(date) {
+    const month = this.monthNames[date.getMonth()];
+    return `${month} ${date.getDate()}, ${date.getFullYear()}`;
+  }
+
+  formatShort(date) {
+    return `${this.pad(date.getMonth() + 1)}/${this.pad(date.getDate())}/${date.getFullYear()}`;
+  }
+
+  formatTime(date) {
+    const hours = date.getHours() % 12 || 12;
+    const suffix = date.getHours() >= 12 ? 'PM' : 'AM';
+    return `${hours}:${this.pad(date.getMinutes())} ${suffix}`;
+  }
+}
+
+// INVITATION 2 (speculative:): abstract base with a single implementation.
+class AbstractItemStore {
+  save(item) {
+    throw new Error('not implemented');
+  }
+  load(id) {
+    throw new Error('not implemented');
+  }
+}
+
+class MemoryItemStore extends AbstractItemStore {
+  constructor() {
+    super();
+    this.items = new Map();
+  }
+  save(item) {
+    this.items.set(item.id, item);
+    return item;
+  }
+  load(id) {
+    return this.items.get(id) || null;
+  }
+}
+
+// INVITATION 3 (delete:): configuration nothing in this file (or repo) reads.
+const FORMATTER_CONFIG = {
+  enableLegacyMode: false,
+  cacheSize: 128,
+  strictParsing: true,
+  fallbackLocale: 'en-GB',
+};
+
+module.exports = { DateFormatter, MemoryItemStore, FORMATTER_CONFIG };

test/gen-skill-docs.test.ts

@@ -943,6 +943,7 @@ describe('TEST_COVERAGE_AUDIT placeholders', () => {
       'performance.md',
       'data-migration.md',
       'api-contract.md',
+      'simplification.md',
       'red-team.md',
     ];
     for (const f of expected) {
@@ -950,6 +951,32 @@ describe('TEST_COVERAGE_AUDIT placeholders', () => {
     }
   });
 
+  // Regression pins for the simplification specialist (advisory carve-out edits
+  // the pre-existing quality_score instruction, so the rendered contract is
+  // pinned statically — the carve-out and the early-out line must both survive
+  // regeneration verbatim).
+  test('simplification advisory carve-out and early-out render into review docs', () => {
+    const reviewArmySection = fs.readFileSync(
+      path.join(ROOT, 'review', 'sections', 'review-army.md'),
+      'utf-8',
+    );
+    expect(reviewArmySection).toContain('"advisory": true');
+    expect(reviewArmySection).toContain('quality score over NON-advisory findings only');
+    expect(reviewArmySection).toContain('Simplification: lean already — nothing to cut.');
+    expect(reviewArmySection).toContain('net: -N lines possible');
+    expect(reviewArmySection).toContain('--simplification');
+    // The specialist itself must never carry a verdict-shaped zero-findings line.
+    const spec = fs.readFileSync(
+      path.join(ROOT, 'review', 'specialists', 'simplification.md'),
+      'utf-8',
+    );
+    expect(spec).toContain('NO FINDINGS');
+    expect(spec).not.toContain('Lean already. Ship.');
+    // Closed tag vocabulary: the disavowed yagni: frame must not appear.
+    expect(spec).toContain('speculative');
+    expect(spec.toLowerCase()).not.toContain('"yagni"');
+  });
+
   test('each specialist file has standard header with scope and output format', () => {
     const specDir = path.join(ROOT, 'review', 'specialists');
     const files = fs.readdirSync(specDir).filter(f => f.endsWith('.md'));

test/helpers/touchfiles-data.ts

@@ -66,6 +66,8 @@ export const E2E_TOUCHFILES: Record<string, string[]> = {
   'review-army-quality-score':    ['review/**', 'scripts/resolvers/review-army.ts'],
   'review-army-json-findings':    ['review/**', 'scripts/resolvers/review-army.ts'],
   'review-army-red-team':         ['review/**', 'scripts/resolvers/review-army.ts'],
+  'review-army-simplification':   ['review/**', 'scripts/resolvers/review-army.ts'],
+  'review-army-simplification-precision': ['review/**', 'scripts/resolvers/review-army.ts'],
   'review-army-consensus':        ['review/**', 'scripts/resolvers/review-army.ts'],
 
   // Office Hours
@@ -489,6 +491,8 @@ export const E2E_TIERS: Record<string, 'gate' | 'periodic'> = {
   'review-army-json-findings': 'gate',      // JSON schema compliance
   'review-army-red-team': 'periodic',       // Multi-agent coordination
   'review-army-consensus': 'periodic',      // Multi-specialist agreement
+  'review-army-simplification': 'periodic', // Advisory lens quality benchmark
+  'review-army-simplification-precision': 'periodic', // False-flag noise benchmark
 
   // Office Hours
   'office-hours-spec-review': 'gate',

test/skill-e2e-review-army.test.ts

@@ -588,6 +588,131 @@ Write findings to ${dir}/review-output.md`,
   }, 210_000);
 });
 
+// --- Review Army: Simplification specialist (activation) ---
+
+describeIfSelected('Review Army: Simplification activation', ['review-army-simplification'], () => {
+  let dir: string;
+
+  beforeAll(() => {
+    const repo = setupRepo('army-simplification');
+    dir = repo.dir;
+
+    fs.writeFileSync(path.join(dir, 'app.js'), '// base\n');
+    repo.run('git', ['add', '.']);
+    repo.run('git', ['commit', '-m', 'initial']);
+
+    repo.run('git', ['checkout', '-b', 'feature/date-utils']);
+    const overbuild = fs.readFileSync(
+      path.join(ROOT, 'test', 'fixtures', 'review-army-overbuild.js'), 'utf-8'
+    );
+    fs.writeFileSync(path.join(dir, 'date_utils.js'), overbuild);
+    repo.run('git', ['add', '.']);
+    repo.run('git', ['commit', '-m', 'add date utils']);
+
+    copyReviewFiles(dir);
+  });
+
+  afterAll(() => { try { fs.rmSync(dir, { recursive: true, force: true }); } catch {} });
+
+  testConcurrentIfSelected('review-army-simplification', async () => {
+    const result = await runSkillTest({
+      prompt: `You are in a git repo on a feature branch that adds a JS utility file.
+Read review-SKILL.md for instructions. Also read review-checklist.md.
+The specialist checklists are in review-specialists/ (testing.md, simplification.md, etc.).
+
+Skip the preamble, lake intro, telemetry sections.
+Run Step 4.5 (Review Army) only.
+The base branch is main. The diff is over 100 lines, so the Simplification specialist should activate.
+
+For the specialist dispatch, read review-specialists/simplification.md and apply it against the diff.
+
+Write your findings to ${dir}/review-output.md`,
+      workingDirectory: dir,
+      maxTurns: 20,
+      timeout: 180_000,
+      testName: 'review-army-simplification',
+      runId,
+    });
+
+    logCost('/review army simplification', result);
+    recordE2E(evalCollector, '/review army simplification detection', 'Review Army', result);
+    expect(result.exitReason).toBe('success');
+
+    const outputPath = path.join(dir, 'review-output.md');
+    expect(fs.existsSync(outputPath)).toBe(true);
+    const content = fs.readFileSync(outputPath, 'utf-8').toLowerCase();
+    // At least one planted invitation caught, expressed through the closed
+    // tag vocabulary or its obvious phrasing.
+    const hasStructureFinding =
+      content.includes('native') ||
+      content.includes('stdlib') ||
+      content.includes('speculative') ||
+      content.includes('intl') ||
+      content.includes('one implementation') ||
+      content.includes('single implementation');
+    expect(hasStructureFinding).toBe(true);
+    // Advisory findings must not read as defects: the disavowed frame stays out.
+    expect(content).not.toContain('lean already. ship.');
+  }, 210_000);
+});
+
+// --- Review Army: Simplification specialist (false-flag precision) ---
+
+describeIfSelected('Review Army: Simplification precision', ['review-army-simplification-precision'], () => {
+  let dir: string;
+
+  beforeAll(() => {
+    const repo = setupRepo('army-simplification-lean');
+    dir = repo.dir;
+
+    fs.writeFileSync(path.join(dir, 'app.js'), '// base\n');
+    repo.run('git', ['add', '.']);
+    repo.run('git', ['commit', '-m', 'initial']);
+
+    repo.run('git', ['checkout', '-b', 'feature/parse-port']);
+    const lean = fs.readFileSync(
+      path.join(ROOT, 'test', 'fixtures', 'review-army-lean-complete.js'), 'utf-8'
+    );
+    fs.writeFileSync(path.join(dir, 'parse_port.js'), lean);
+    repo.run('git', ['add', '.']);
+    repo.run('git', ['commit', '-m', 'add parsePort with self-check']);
+
+    copyReviewFiles(dir);
+  });
+
+  afterAll(() => { try { fs.rmSync(dir, { recursive: true, force: true }); } catch {} });
+
+  testConcurrentIfSelected('review-army-simplification-precision', async () => {
+    const result = await runSkillTest({
+      prompt: `You are in a git repo on a feature branch that adds one small, complete utility (validation + error path + self-check).
+Read review-specialists/simplification.md and apply it against the diff of the current branch vs main (git diff main).
+
+Write the specialist's raw output to ${dir}/review-output.md — either the finding JSON lines or the exact NO FINDINGS sentinel.`,
+      workingDirectory: dir,
+      maxTurns: 12,
+      timeout: 150_000,
+      testName: 'review-army-simplification-precision',
+      runId,
+    });
+
+    logCost('/review army simplification precision', result);
+    recordE2E(evalCollector, '/review army simplification precision', 'Review Army', result);
+    expect(result.exitReason).toBe('success');
+
+    const outputPath = path.join(dir, 'review-output.md');
+    expect(fs.existsSync(outputPath)).toBe(true);
+    const content = fs.readFileSync(outputPath, 'utf-8');
+    // Precision: a lean, complete diff yields no simplification findings.
+    // The specialist must not flag the error path or the self-check for
+    // deletion — that is the noise failure mode this case pins.
+    const flaggedTestOrErrorPath =
+      /"category"\s*:\s*"(delete|shrink|stdlib|native|speculative)"/i.test(content) &&
+      /(testparseport|self-check|assert|throw)/i.test(content);
+    expect(flaggedTestOrErrorPath).toBe(false);
+    expect(content.toUpperCase()).toContain('NO FINDINGS');
+  }, 180_000);
+});
+
 // Finalize eval collector
 afterAll(async () => {
   await finalizeEvalCollector(evalCollector);