feat: contributor mode, session awareness, recommendation format (#90)

* feat: contributor mode, session awareness, universal RECOMMENDATION format

- Rename {{UPDATE_CHECK}} → {{PREAMBLE}} across all 10 skill templates
- Add session tracking (touch ~/.gstack/sessions/$PPID, count active sessions)
- ELI16 mode when 3+ concurrent sessions detected (re-ground user on context)
- Contributor mode: auto-file field reports to ~/.gstack/contributor-logs/
- Universal AskUserQuestion format: context → question → RECOMMENDATION → options
- Update plan-ceo-review and plan-eng-review to reference preamble baseline
- Add vendored symlink awareness section to CLAUDE.md
- Rewrite CONTRIBUTING.md with contributor workflow and cross-project testing
- Add tests for contributor mode and session awareness in generated output
- Add E2E eval for contributor mode report filing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: add Enum & Value Completeness to /review critical checklist

New CRITICAL review category that traces new enum values, status strings,
and type constants through every consumer outside the diff. Catches the
class of bugs where a new value is added but not handled in all switch/case
chains, allowlists, or frontend-backend contracts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* chore: bump v0.4.1, user-facing changelog, update qa-only template and architecture docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: add CHANGELOG style guide — user-facing, sell the feature

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: rewrite v0.4.1 changelog to be user-facing and sell the features

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add evals for RECOMMENDATION format, session awareness, and enum completeness

Free tests (Tier 1): RECOMMENDATION format + session awareness in all
preamble SKILL.md files, enum completeness checklist structure and CRITICAL
classification.

E2E eval: /review catches missed enum handlers when a new status value
is added but not handled in case/switch and notify methods.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add E2E eval for session awareness ELI16 mode

Stubs _SESSIONS=4, gives agent a decision point on feature/add-payments
branch, verifies the output re-grounds the user with project, branch,
context, and RECOMMENDATION — the ELI16 mode behavior for 3+ sessions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: contributor mode eval marked FAIL due to expected browse error

The test intentionally runs a nonexistent binary to trigger contributor
mode. The session runner's browse error detection catches "no such file
or directory...browse" and sets browseErrors, causing recordE2E to mark
passed=false. Override passed to check only exitReason since the browse
error is the expected scenario.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

test/fixtures/review-eval-enum-diff.rb

@@ -0,0 +1,30 @@
+# Feature branch version: adds "returned" status but misses consumers
+class Order < ApplicationRecord
+  STATUSES = %w[pending processing shipped delivered returned].freeze
+
+  validates :status, inclusion: { in: STATUSES }
+
+  def display_status
+    case status
+    when 'pending'    then 'Awaiting processing'
+    when 'processing' then 'Being prepared'
+    when 'shipped'    then 'On the way'
+    when 'delivered'  then 'Delivered'
+    # BUG: 'returned' not handled — falls through to nil
+    end
+  end
+
+  def can_cancel?
+    # BUG: should 'returned' be cancellable? Not considered.
+    %w[pending processing].include?(status)
+  end
+
+  def notify_customer
+    case status
+    when 'pending'    then OrderMailer.confirmation(self).deliver_later
+    when 'shipped'    then OrderMailer.shipped(self).deliver_later
+    when 'delivered'  then OrderMailer.delivered(self).deliver_later
+    # BUG: 'returned' has no notification — customer won't know return was received
+    end
+  end
+end

test/fixtures/review-eval-enum.rb

@@ -0,0 +1,27 @@
+# Existing file on main: order model with status handling
+class Order < ApplicationRecord
+  STATUSES = %w[pending processing shipped delivered].freeze
+
+  validates :status, inclusion: { in: STATUSES }
+
+  def display_status
+    case status
+    when 'pending'    then 'Awaiting processing'
+    when 'processing' then 'Being prepared'
+    when 'shipped'    then 'On the way'
+    when 'delivered'  then 'Delivered'
+    end
+  end
+
+  def can_cancel?
+    %w[pending processing].include?(status)
+  end
+
+  def notify_customer
+    case status
+    when 'pending'    then OrderMailer.confirmation(self).deliver_later
+    when 'shipped'    then OrderMailer.shipped(self).deliver_later
+    when 'delivered'  then OrderMailer.delivered(self).deliver_later
+    end
+  end
+end

test/gen-skill-docs.test.ts

@@ -125,10 +125,26 @@ describe('gen-skill-docs', () => {
     const rootTmpl = fs.readFileSync(path.join(ROOT, 'SKILL.md.tmpl'), 'utf-8');
     expect(rootTmpl).toContain('{{COMMAND_REFERENCE}}');
     expect(rootTmpl).toContain('{{SNAPSHOT_FLAGS}}');
+    expect(rootTmpl).toContain('{{PREAMBLE}}');
 
     const browseTmpl = fs.readFileSync(path.join(ROOT, 'browse', 'SKILL.md.tmpl'), 'utf-8');
     expect(browseTmpl).toContain('{{COMMAND_REFERENCE}}');
     expect(browseTmpl).toContain('{{SNAPSHOT_FLAGS}}');
+    expect(browseTmpl).toContain('{{PREAMBLE}}');
+  });
+
+  test('generated SKILL.md contains contributor mode check', () => {
+    const content = fs.readFileSync(path.join(ROOT, 'SKILL.md'), 'utf-8');
+    expect(content).toContain('Contributor Mode');
+    expect(content).toContain('gstack_contributor');
+    expect(content).toContain('contributor-logs');
+  });
+
+  test('generated SKILL.md contains session awareness', () => {
+    const content = fs.readFileSync(path.join(ROOT, 'SKILL.md'), 'utf-8');
+    expect(content).toContain('_SESSIONS');
+    expect(content).toContain('RECOMMENDATION');
+    expect(content).toContain('ELI16');
   });
 
   test('qa and qa-only templates use QA_METHODOLOGY placeholder', () => {

test/skill-e2e.test.ts

@@ -280,6 +280,124 @@ Report the exact output — either "READY: <path>" or "NEEDS_SETUP".`,
     // Clean up
     try { fs.rmSync(nonGitDir, { recursive: true, force: true }); } catch {}
   }, 60_000);
+
+  test('contributor mode files a report on gstack error', async () => {
+    const contribDir = fs.mkdtempSync(path.join(os.tmpdir(), 'skill-e2e-contrib-'));
+    const logsDir = path.join(contribDir, 'contributor-logs');
+    fs.mkdirSync(logsDir, { recursive: true });
+
+    // Extract contributor mode instructions from generated SKILL.md
+    const skillMd = fs.readFileSync(path.join(ROOT, 'SKILL.md'), 'utf-8');
+    const contribStart = skillMd.indexOf('## Contributor Mode');
+    const contribEnd = skillMd.indexOf('\n## ', contribStart + 1);
+    const contribBlock = skillMd.slice(contribStart, contribEnd > 0 ? contribEnd : undefined);
+
+    const result = await runSkillTest({
+      prompt: `You are in contributor mode (_CONTRIB=true).
+
+${contribBlock}
+
+OVERRIDE: Write contributor logs to ${logsDir}/ instead of ~/.gstack/contributor-logs/
+
+Now try this browse command (it will fail — there is no binary at this path):
+/nonexistent/path/browse goto https://example.com
+
+This is a gstack issue (the browse binary is missing/misconfigured).
+File a contributor report about this issue. Then tell me what you filed.`,
+      workingDirectory: contribDir,
+      maxTurns: 8,
+      timeout: 60_000,
+      testName: 'contributor-mode',
+      runId,
+    });
+
+    logCost('contributor mode', result);
+    // Override passed: this test intentionally triggers a browse error (nonexistent binary)
+    // so browseErrors will be non-empty — that's expected, not a failure
+    recordE2E('contributor mode report', 'Skill E2E tests', result, {
+      passed: result.exitReason === 'success',
+    });
+
+    // Verify a contributor log was created with expected format
+    const logFiles = fs.readdirSync(logsDir).filter(f => f.endsWith('.md'));
+    expect(logFiles.length).toBeGreaterThan(0);
+
+    const logContent = fs.readFileSync(path.join(logsDir, logFiles[0]), 'utf-8');
+    expect(logContent).toContain('Hey gstack team');
+    expect(logContent).toContain('What I was trying to do');
+    expect(logContent).toContain('What happened instead');
+
+    // Clean up
+    try { fs.rmSync(contribDir, { recursive: true, force: true }); } catch {}
+  }, 90_000);
+
+  test('session awareness adds ELI16 context when _SESSIONS >= 3', async () => {
+    const sessionDir = fs.mkdtempSync(path.join(os.tmpdir(), 'skill-e2e-session-'));
+
+    // Set up a git repo so there's project/branch context to reference
+    const run = (cmd: string, args: string[]) =>
+      spawnSync(cmd, args, { cwd: sessionDir, stdio: 'pipe', timeout: 5000 });
+    run('git', ['init']);
+    run('git', ['config', 'user.email', 'test@test.com']);
+    run('git', ['config', 'user.name', 'Test']);
+    fs.writeFileSync(path.join(sessionDir, 'app.rb'), '# my app\n');
+    run('git', ['add', '.']);
+    run('git', ['commit', '-m', 'init']);
+    run('git', ['checkout', '-b', 'feature/add-payments']);
+    // Add a remote so the agent can derive a project name
+    run('git', ['remote', 'add', 'origin', 'https://github.com/acme/billing-app.git']);
+
+    // Extract AskUserQuestion format instructions from generated SKILL.md
+    const skillMd = fs.readFileSync(path.join(ROOT, 'SKILL.md'), 'utf-8');
+    const aqStart = skillMd.indexOf('## AskUserQuestion Format');
+    const aqEnd = skillMd.indexOf('\n## ', aqStart + 1);
+    const aqBlock = skillMd.slice(aqStart, aqEnd > 0 ? aqEnd : undefined);
+
+    const outputPath = path.join(sessionDir, 'question-output.md');
+
+    const result = await runSkillTest({
+      prompt: `You are running a gstack skill. The session preamble detected _SESSIONS=4 (the user has 4 gstack windows open).
+
+${aqBlock}
+
+You are on branch feature/add-payments in the billing-app project. You were reviewing a plan to add Stripe integration.
+
+You've hit a decision point: the plan doesn't specify whether to use Stripe Checkout (hosted) or Stripe Elements (embedded). You need to ask the user which approach to use.
+
+Since this is non-interactive, DO NOT actually call AskUserQuestion. Instead, write the EXACT text you would display to the user (the full AskUserQuestion content) to the file: ${outputPath}
+
+Remember: _SESSIONS=4, so ELI16 mode is active. The user is juggling multiple windows and may not remember what this conversation is about. Re-ground them.`,
+      workingDirectory: sessionDir,
+      maxTurns: 8,
+      timeout: 60_000,
+      testName: 'session-awareness',
+      runId,
+    });
+
+    logCost('session awareness', result);
+    recordE2E('session awareness ELI16', 'Skill E2E tests', result);
+
+    // Verify the output contains ELI16 re-grounding context
+    if (fs.existsSync(outputPath)) {
+      const output = fs.readFileSync(outputPath, 'utf-8');
+      const lower = output.toLowerCase();
+      // Must mention project name
+      expect(lower.includes('billing') || lower.includes('acme')).toBe(true);
+      // Must mention branch
+      expect(lower.includes('payment') || lower.includes('feature')).toBe(true);
+      // Must mention what we're working on
+      expect(lower.includes('stripe') || lower.includes('checkout') || lower.includes('payment')).toBe(true);
+      // Must have a RECOMMENDATION
+      expect(output).toContain('RECOMMENDATION');
+    } else {
+      // Check agent output as fallback
+      const output = result.output || '';
+      expect(output).toContain('RECOMMENDATION');
+    }
+
+    // Clean up
+    try { fs.rmSync(sessionDir, { recursive: true, force: true }); } catch {}
+  }, 90_000);
 });
 
 // --- B4: QA skill E2E ---
@@ -392,6 +510,78 @@ Write your review findings to ${reviewDir}/review-output.md`,
   }, 120_000);
 });
 
+// --- Review: Enum completeness E2E ---
+
+describeE2E('Review enum completeness E2E', () => {
+  let enumDir: string;
+
+  beforeAll(() => {
+    enumDir = fs.mkdtempSync(path.join(os.tmpdir(), 'skill-e2e-enum-'));
+
+    const run = (cmd: string, args: string[]) =>
+      spawnSync(cmd, args, { cwd: enumDir, stdio: 'pipe', timeout: 5000 });
+
+    run('git', ['init']);
+    run('git', ['config', 'user.email', 'test@test.com']);
+    run('git', ['config', 'user.name', 'Test']);
+
+    // Commit baseline on main — order model with 4 statuses
+    const baseContent = fs.readFileSync(path.join(ROOT, 'test', 'fixtures', 'review-eval-enum.rb'), 'utf-8');
+    fs.writeFileSync(path.join(enumDir, 'order.rb'), baseContent);
+    run('git', ['add', 'order.rb']);
+    run('git', ['commit', '-m', 'initial order model']);
+
+    // Feature branch adds "returned" status but misses handlers
+    run('git', ['checkout', '-b', 'feature/add-returned-status']);
+    const diffContent = fs.readFileSync(path.join(ROOT, 'test', 'fixtures', 'review-eval-enum-diff.rb'), 'utf-8');
+    fs.writeFileSync(path.join(enumDir, 'order.rb'), diffContent);
+    run('git', ['add', 'order.rb']);
+    run('git', ['commit', '-m', 'add returned status']);
+
+    // Copy review skill files
+    fs.copyFileSync(path.join(ROOT, 'review', 'SKILL.md'), path.join(enumDir, 'review-SKILL.md'));
+    fs.copyFileSync(path.join(ROOT, 'review', 'checklist.md'), path.join(enumDir, 'review-checklist.md'));
+    fs.copyFileSync(path.join(ROOT, 'review', 'greptile-triage.md'), path.join(enumDir, 'review-greptile-triage.md'));
+  });
+
+  afterAll(() => {
+    try { fs.rmSync(enumDir, { recursive: true, force: true }); } catch {}
+  });
+
+  test('/review catches missing enum handlers for new status value', async () => {
+    const result = await runSkillTest({
+      prompt: `You are in a git repo on branch feature/add-returned-status with changes against main.
+Read review-SKILL.md for the review workflow instructions.
+Also read review-checklist.md and apply it — pay special attention to the Enum & Value Completeness section.
+Run /review on the current diff (git diff main...HEAD).
+Write your review findings to ${enumDir}/review-output.md
+
+The diff adds a new "returned" status to the Order model. Your job is to check if all consumers handle it.`,
+      workingDirectory: enumDir,
+      maxTurns: 15,
+      timeout: 90_000,
+      testName: 'review-enum-completeness',
+      runId,
+    });
+
+    logCost('/review enum', result);
+    recordE2E('/review enum completeness', 'Review enum completeness E2E', result);
+    expect(result.exitReason).toBe('success');
+
+    // Verify the review caught the missing enum handlers
+    const reviewPath = path.join(enumDir, 'review-output.md');
+    if (fs.existsSync(reviewPath)) {
+      const review = fs.readFileSync(reviewPath, 'utf-8');
+      // Should mention the missing "returned" handling in at least one of the methods
+      const mentionsReturned = review.toLowerCase().includes('returned');
+      const mentionsEnum = review.toLowerCase().includes('enum') || review.toLowerCase().includes('status');
+      const mentionsCritical = review.toLowerCase().includes('critical');
+      expect(mentionsReturned).toBe(true);
+      expect(mentionsEnum || mentionsCritical).toBe(true);
+    }
+  }, 120_000);
+});
+
 // --- B6/B7/B8: Planted-bug outcome evals ---
 
 // Outcome evals also need ANTHROPIC_API_KEY for the LLM judge

test/skill-validation.test.ts

@@ -411,6 +411,66 @@ describe('TODOS-format.md reference consistency', () => {
   });
 });
 
+// --- v0.4.1 feature coverage: RECOMMENDATION format, session awareness, enum completeness ---
+
+describe('v0.4.1 preamble features', () => {
+  const skillsWithPreamble = [
+    'SKILL.md', 'browse/SKILL.md', 'qa/SKILL.md',
+    'qa-only/SKILL.md',
+    'setup-browser-cookies/SKILL.md',
+    'ship/SKILL.md', 'review/SKILL.md',
+    'plan-ceo-review/SKILL.md', 'plan-eng-review/SKILL.md',
+    'retro/SKILL.md',
+  ];
+
+  for (const skill of skillsWithPreamble) {
+    test(`${skill} contains RECOMMENDATION format`, () => {
+      const content = fs.readFileSync(path.join(ROOT, skill), 'utf-8');
+      expect(content).toContain('RECOMMENDATION: Choose');
+      expect(content).toContain('AskUserQuestion');
+    });
+
+    test(`${skill} contains session awareness`, () => {
+      const content = fs.readFileSync(path.join(ROOT, skill), 'utf-8');
+      expect(content).toContain('_SESSIONS');
+      expect(content).toContain('ELI16');
+    });
+  }
+});
+
+describe('Enum & Value Completeness in review checklist', () => {
+  const checklist = fs.readFileSync(path.join(ROOT, 'review', 'checklist.md'), 'utf-8');
+
+  test('checklist has Enum & Value Completeness section', () => {
+    expect(checklist).toContain('Enum & Value Completeness');
+  });
+
+  test('Enum & Value Completeness is classified as CRITICAL', () => {
+    // It should appear under Pass 1 — CRITICAL, not Pass 2
+    const pass1Start = checklist.indexOf('### Pass 1');
+    const pass2Start = checklist.indexOf('### Pass 2');
+    const enumStart = checklist.indexOf('Enum & Value Completeness');
+    expect(enumStart).toBeGreaterThan(pass1Start);
+    expect(enumStart).toBeLessThan(pass2Start);
+  });
+
+  test('Enum & Value Completeness mentions tracing through consumers', () => {
+    expect(checklist).toContain('Trace it through every consumer');
+    expect(checklist).toContain('case');
+    expect(checklist).toContain('allowlist');
+  });
+
+  test('Enum & Value Completeness is in the gate classification as CRITICAL', () => {
+    const gateSection = checklist.slice(checklist.indexOf('## Gate Classification'));
+    // The ASCII art has CRITICAL on the left and INFORMATIONAL on the right
+    // Enum & Value Completeness should appear on a line with the CRITICAL tree (├─ or └─)
+    const enumLine = gateSection.split('\n').find(l => l.includes('Enum & Value Completeness'));
+    expect(enumLine).toBeDefined();
+    // It's on the left (CRITICAL) side — starts with ├─ or └─
+    expect(enumLine!.trimStart().startsWith('├─') || enumLine!.trimStart().startsWith('└─')).toBe(true);
+  });
+});
+
 // --- Part 7: Planted-bug fixture validation (A4) ---
 
 describe('Planted-bug fixture validation', () => {