diff --git a/extensions/anthropic/cli-shared.ts b/extensions/anthropic/cli-shared.ts
index d56cc1979e1..a62948e8bb2 100644
--- a/extensions/anthropic/cli-shared.ts
+++ b/extensions/anthropic/cli-shared.ts
@@ -1,4 +1,5 @@
 import type { CliBackendConfig } from "openclaw/plugin-sdk/cli-backend";
+import { normalizeOptionalLowercaseString } from "openclaw/plugin-sdk/text-runtime";
 
 export const CLAUDE_CLI_BACKEND_ID = "claude-cli";
 export const CLAUDE_CLI_DEFAULT_MODEL_REF = `${CLAUDE_CLI_BACKEND_ID}/claude-sonnet-4-6`;
@@ -92,7 +93,7 @@ const CLAUDE_SETTING_SOURCES_ARG = "--setting-sources";
 const CLAUDE_SAFE_SETTING_SOURCES = "user";
 
 export function isClaudeCliProvider(providerId: string): boolean {
-  return providerId.trim().toLowerCase() === CLAUDE_CLI_BACKEND_ID;
+  return normalizeOptionalLowercaseString(providerId) === CLAUDE_CLI_BACKEND_ID;
 }
 
 export function normalizeClaudePermissionArgs(args?: string[]): string[] | undefined {
diff --git a/extensions/browser/src/browser/session-tab-registry.ts b/extensions/browser/src/browser/session-tab-registry.ts
index b81ceac3060..8ecf4ae7a9a 100644
--- a/extensions/browser/src/browser/session-tab-registry.ts
+++ b/extensions/browser/src/browser/session-tab-registry.ts
@@ -1,3 +1,4 @@
+import { normalizeOptionalLowercaseString } from "openclaw/plugin-sdk/text-runtime";
 import { browserCloseTab } from "./client.js";
 
 export type TrackedSessionBrowserTab = {
@@ -11,7 +12,7 @@ export type TrackedSessionBrowserTab = {
 const trackedTabsBySession = new Map<string, Map<string, TrackedSessionBrowserTab>>();
 
 function normalizeSessionKey(raw: string): string {
-  return raw.trim().toLowerCase();
+  return normalizeOptionalLowercaseString(raw) ?? "";
 }
 
 function normalizeTargetId(raw: string): string {
@@ -19,11 +20,7 @@ function normalizeTargetId(raw: string): string {
 }
 
 function normalizeProfile(raw?: string): string | undefined {
-  if (!raw) {
-    return undefined;
-  }
-  const trimmed = raw.trim();
-  return trimmed ? trimmed.toLowerCase() : undefined;
+  return normalizeOptionalLowercaseString(raw);
 }
 
 function normalizeBaseUrl(raw?: string): string | undefined {
diff --git a/extensions/discord/src/directory-live.ts b/extensions/discord/src/directory-live.ts
index 9e1bd221612..071a613ca97 100644
--- a/extensions/discord/src/directory-live.ts
+++ b/extensions/discord/src/directory-live.ts
@@ -2,6 +2,7 @@ import type {
   ChannelDirectoryEntry,
   DirectoryConfigParams,
 } from "openclaw/plugin-sdk/directory-runtime";
+import { normalizeOptionalLowercaseString } from "openclaw/plugin-sdk/text-runtime";
 import { resolveDiscordAccount } from "./accounts.js";
 import { fetchDiscord } from "./api.js";
 import { rememberDiscordDirectoryUser } from "./directory-cache.js";
@@ -15,7 +16,7 @@ type DiscordChannel = { id: string; name?: string | null };
 type DiscordDirectoryAccess = { token: string; query: string; accountId: string };
 
 function normalizeQuery(value?: string | null): string {
-  return value?.trim().toLowerCase() ?? "";
+  return normalizeOptionalLowercaseString(value) ?? "";
 }
 
 function buildUserRank(user: DiscordUser): number {
diff --git a/extensions/feishu/src/card-ux-launcher.ts b/extensions/feishu/src/card-ux-launcher.ts
index e72cea82c05..015572cd6b6 100644
--- a/extensions/feishu/src/card-ux-launcher.ts
+++ b/extensions/feishu/src/card-ux-launcher.ts
@@ -1,3 +1,4 @@
+import { normalizeOptionalLowercaseString } from "openclaw/plugin-sdk/text-runtime";
 import type { ClawdbotConfig, RuntimeEnv } from "../runtime-api.js";
 import { createFeishuCardInteractionEnvelope } from "./card-interaction.js";
 import { FEISHU_APPROVAL_REQUEST_ACTION } from "./card-ux-approval.js";
@@ -9,7 +10,7 @@ export const FEISHU_QUICK_ACTION_CARD_TTL_MS = 10 * 60_000;
 const QUICK_ACTION_MENU_KEYS = new Set(["quick-actions", "quick_actions", "launcher"]);
 
 export function isFeishuQuickActionMenuEventKey(eventKey: string): boolean {
-  return QUICK_ACTION_MENU_KEYS.has(eventKey.trim().toLowerCase());
+  return QUICK_ACTION_MENU_KEYS.has(normalizeOptionalLowercaseString(eventKey) ?? "");
 }
 
 export function createQuickActionLauncherCard(params: {
diff --git a/extensions/google/provider-models.ts b/extensions/google/provider-models.ts
index e90f0178f35..8e380da773a 100644
--- a/extensions/google/provider-models.ts
+++ b/extensions/google/provider-models.ts
@@ -3,6 +3,7 @@ import type {
   ProviderRuntimeModel,
 } from "openclaw/plugin-sdk/plugin-entry";
 import { cloneFirstTemplateModel } from "openclaw/plugin-sdk/provider-model-shared";
+import { normalizeOptionalLowercaseString } from "openclaw/plugin-sdk/text-runtime";
 
 const GOOGLE_GEMINI_CLI_PROVIDER_ID = "google-gemini-cli";
 const GEMINI_2_5_PRO_PREFIX = "gemini-2.5-pro";
@@ -54,7 +55,7 @@ function cloneGoogleTemplateModel(params: {
 }
 
 function isGoogleGeminiCliProvider(providerId: string): boolean {
-  return providerId.trim().toLowerCase() === GOOGLE_GEMINI_CLI_PROVIDER_ID;
+  return normalizeOptionalLowercaseString(providerId) === GOOGLE_GEMINI_CLI_PROVIDER_ID;
 }
 
 function templateIdsForProvider(
diff --git a/extensions/matrix/src/resolve-targets.ts b/extensions/matrix/src/resolve-targets.ts
index 4d2f7843006..4343646915c 100644
--- a/extensions/matrix/src/resolve-targets.ts
+++ b/extensions/matrix/src/resolve-targets.ts
@@ -1,3 +1,4 @@
+import { normalizeOptionalLowercaseString } from "openclaw/plugin-sdk/text-runtime";
 import { listMatrixDirectoryGroupsLive, listMatrixDirectoryPeersLive } from "./directory-live.js";
 import { isMatrixQualifiedUserId, normalizeMatrixMessagingTarget } from "./matrix/target-ids.js";
 import type {
@@ -8,7 +9,7 @@ import type {
 } from "./runtime-api.js";
 
 function normalizeLookupQuery(query: string): string {
-  return query.trim().toLowerCase();
+  return normalizeOptionalLowercaseString(query) ?? "";
 }
 
 function findExactDirectoryMatches(
@@ -20,9 +21,9 @@ function findExactDirectoryMatches(
     return [];
   }
   return matches.filter((match) => {
-    const id = match.id.trim().toLowerCase();
-    const name = match.name?.trim().toLowerCase();
-    const handle = match.handle?.trim().toLowerCase();
+    const id = normalizeOptionalLowercaseString(match.id);
+    const name = normalizeOptionalLowercaseString(match.name);
+    const handle = normalizeOptionalLowercaseString(match.handle);
     return normalized === id || normalized === name || normalized === handle;
   });
 }
diff --git a/extensions/telegram/src/command-config.ts b/extensions/telegram/src/command-config.ts
index e7c316791d7..7ee06001c8d 100644
--- a/extensions/telegram/src/command-config.ts
+++ b/extensions/telegram/src/command-config.ts
@@ -1,3 +1,5 @@
+import { normalizeOptionalLowercaseString } from "openclaw/plugin-sdk/text-runtime";
+
 export const TELEGRAM_COMMAND_NAME_PATTERN = /^[a-z0-9_]{1,32}$/;
 
 export type TelegramCustomCommandInput = {
@@ -17,7 +19,7 @@ export function normalizeTelegramCommandName(value: string): string {
     return "";
   }
   const withoutSlash = trimmed.startsWith("/") ? trimmed.slice(1) : trimmed;
-  return withoutSlash.trim().toLowerCase().replace(/-/g, "_");
+  return (normalizeOptionalLowercaseString(withoutSlash) ?? "").replace(/-/g, "_");
 }
 
 export function normalizeTelegramCommandDescription(value: string): string {
diff --git a/extensions/whatsapp/src/auto-reply/heartbeat-runner.ts b/extensions/whatsapp/src/auto-reply/heartbeat-runner.ts
index 46287758c8b..83c27548c78 100644
--- a/extensions/whatsapp/src/auto-reply/heartbeat-runner.ts
+++ b/extensions/whatsapp/src/auto-reply/heartbeat-runner.ts
@@ -1,3 +1,4 @@
+import { normalizeOptionalLowercaseString } from "openclaw/plugin-sdk/text-runtime";
 import { newConnectionId } from "../reconnect.js";
 import {
   DEFAULT_HEARTBEAT_ACK_MAX_CHARS,
@@ -31,7 +32,7 @@ import { getSessionSnapshot } from "./session-snapshot.js";
 function resolveDefaultAgentIdFromConfig(cfg: ReturnType<typeof loadConfig>): string {
   const agents = cfg.agents?.list ?? [];
   const chosen = agents.find((agent) => agent?.default)?.id ?? agents[0]?.id ?? "main";
-  return chosen.trim().toLowerCase() || "main";
+  return normalizeOptionalLowercaseString(chosen) ?? "main";
 }
 
 export async function runWebHeartbeatOnce(opts: {