feat: add codex review failover and suppress output hardening

src/output-suppression.ts

@@ -0,0 +1,65 @@
+import { randomBytes } from 'crypto';
+
+import {
+  CLAUDE_SERVICE_ID,
+  CODEX_REVIEW_SERVICE_ID,
+  normalizeServiceId,
+} from './config.js';
+
+const ANY_SUPPRESS_TOKEN_PATTERN = /__EJ_SUPPRESS_[a-f0-9]{24,}(?:__)?/g;
+const EXACT_ANY_SUPPRESS_TOKEN_PATTERN = /^__EJ_SUPPRESS_[a-f0-9]{24,}(?:__)?$/;
+
+export function createSuppressToken(): string {
+  return `__EJ_SUPPRESS_${randomBytes(12).toString('hex')}__`;
+}
+
+export function shouldEnableSuppressOutputForService(
+  serviceId: string | undefined,
+): boolean {
+  if (!serviceId) return false;
+  const normalized = normalizeServiceId(serviceId);
+  return (
+    normalized === CLAUDE_SERVICE_ID ||
+    normalized === CODEX_REVIEW_SERVICE_ID
+  );
+}
+
+export function classifySuppressTokenOutput(
+  rawText: string,
+  suppressToken: string | undefined,
+): 'exact' | 'mixed' | 'none' {
+  const trimmed = rawText.trim();
+  if ((suppressToken && trimmed === suppressToken) || EXACT_ANY_SUPPRESS_TOKEN_PATTERN.test(trimmed)) {
+    return 'exact';
+  }
+  if (suppressToken && rawText.includes(suppressToken)) {
+    return 'mixed';
+  }
+  ANY_SUPPRESS_TOKEN_PATTERN.lastIndex = 0;
+  return ANY_SUPPRESS_TOKEN_PATTERN.test(rawText) ? 'mixed' : 'none';
+}
+
+export function buildSuppressTokenPrompt(
+  prompt: string,
+  suppressToken: string | undefined,
+  options?: {
+    reviewerMode?: boolean;
+  },
+): string {
+  if (!suppressToken) return prompt;
+
+  const lines = [
+    '[OUTPUT CONTROL]',
+    `If you have no user-visible content to send for this turn, output exactly this token and nothing else: ${suppressToken}`,
+    'Do not wrap the token in backticks or code fences.',
+    'Do not combine the token with any other text.',
+  ];
+
+  if (options?.reviewerMode) {
+    lines.push(
+      'If you are only agreeing, mirroring, or restating without adding a concrete correction, risk, missing prerequisite, test gap, or code change, output only the token.',
+    );
+  }
+
+  return `${lines.join('\n')}\n\n${prompt}`;
+}