fix: surface warn-only PreToolUse hooks (#2084)

scripts/hooks/pretooluse-visible-output.js

@@ -0,0 +1,41 @@
+#!/usr/bin/env node
+'use strict';
+
+function normalizeAdditionalContext(value) {
+  if (Array.isArray(value)) {
+    return value
+      .map(item => String(item || '').trim())
+      .filter(Boolean)
+      .join('\n');
+  }
+
+  return String(value || '').trim();
+}
+
+function combineAdditionalContext(current, next) {
+  const currentText = normalizeAdditionalContext(current);
+  const nextText = normalizeAdditionalContext(next);
+
+  if (!currentText) return nextText;
+  if (!nextText) return currentText;
+
+  return `${currentText}\n${nextText}`;
+}
+
+function buildPreToolUseAdditionalContext(value) {
+  const additionalContext = normalizeAdditionalContext(value);
+  if (!additionalContext) return '';
+
+  return JSON.stringify({
+    hookSpecificOutput: {
+      hookEventName: 'PreToolUse',
+      additionalContext,
+    },
+  });
+}
+
+module.exports = {
+  buildPreToolUseAdditionalContext,
+  combineAdditionalContext,
+  normalizeAdditionalContext,
+};