perf: cache compiled redact patterns

src/agents/tools/web-shared.ts

@@ -35,6 +35,9 @@ export function readCache<T>(
     cache.delete(key);
     return null;
   }
+  // Promote to most-recent position for LRU eviction.
+  cache.delete(key);
+  cache.set(key, entry);
   return { value: entry.value, cached: true };
 }
 
@@ -47,16 +50,33 @@ export function writeCache<T>(
   if (ttlMs <= 0) {
     return;
   }
+  // Remove existing entry so .set() moves it to the end (LRU order).
+  cache.delete(key);
   if (cache.size >= DEFAULT_CACHE_MAX_ENTRIES) {
-    const oldest = cache.keys().next();
-    if (!oldest.done) {
-      cache.delete(oldest.value);
+    // Evict expired entries first, then fall back to LRU (oldest insertion order).
+    const now = Date.now();
+    let evicted = false;
+    for (const [k, v] of cache) {
+      if (now > v.expiresAt) {
+        cache.delete(k);
+        evicted = true;
+        if (cache.size < DEFAULT_CACHE_MAX_ENTRIES) {
+          break;
+        }
+      }
+    }
+    if (!evicted || cache.size >= DEFAULT_CACHE_MAX_ENTRIES) {
+      const oldest = cache.keys().next();
+      if (!oldest.done) {
+        cache.delete(oldest.value);
+      }
     }
   }
+  const now = Date.now();
   cache.set(key, {
     value,
-    expiresAt: Date.now() + ttlMs,
-    insertedAt: Date.now(),
+    expiresAt: now + ttlMs,
+    insertedAt: now,
   });
 }
 

src/logging/redact.ts

@@ -121,23 +121,53 @@ function resolveConfigRedaction(): RedactOptions {
   };
 }
 
+/* ── Cached resolution ── */
+
+let _cachedConfig: RedactOptions | undefined;
+let _cachedCompiledPatterns: RegExp[] | undefined;
+let _cachedPatternSource: string[] | undefined;
+
+function getCachedConfig(): RedactOptions {
+  if (!_cachedConfig) {
+    _cachedConfig = resolveConfigRedaction();
+  }
+  return _cachedConfig;
+}
+
+function getCachedPatterns(source?: string[]): RegExp[] {
+  const key = source?.length ? source : DEFAULT_REDACT_PATTERNS;
+  if (_cachedCompiledPatterns && _cachedPatternSource === key) {
+    return _cachedCompiledPatterns;
+  }
+  _cachedPatternSource = key;
+  _cachedCompiledPatterns = resolvePatterns(key);
+  return _cachedCompiledPatterns;
+}
+
+/** Clear the cached config and patterns (useful for testing or config reload). */
+export function clearRedactCache(): void {
+  _cachedConfig = undefined;
+  _cachedCompiledPatterns = undefined;
+  _cachedPatternSource = undefined;
+}
+
 export function redactSensitiveText(text: string, options?: RedactOptions): string {
   if (!text) {
     return text;
   }
-  const resolved = options ?? resolveConfigRedaction();
+  const resolved = options ?? getCachedConfig();
   if (normalizeMode(resolved.mode) === "off") {
     return text;
   }
-  const patterns = resolvePatterns(resolved.patterns);
+  const patterns = getCachedPatterns(resolved.patterns);
   if (!patterns.length) {
     return text;
   }
   return redactText(text, patterns);
 }
 
 export function redactToolDetail(detail: string): string {
-  const resolved = resolveConfigRedaction();
+  const resolved = getCachedConfig();
   if (normalizeMode(resolved.mode) !== "tools") {
     return detail;
   }