diff --git a/src/agents/pi-embedded-runner/run/attempt.spawn-workspace.test-support.ts b/src/agents/pi-embedded-runner/run/attempt.spawn-workspace.test-support.ts
index 6b5175ea2b1..947bc05509d 100644
--- a/src/agents/pi-embedded-runner/run/attempt.spawn-workspace.test-support.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.spawn-workspace.test-support.ts
@@ -13,6 +13,7 @@ import type {
   IngestResult,
 } from "../../../context-engine/types.js";
 import { formatErrorMessage } from "../../../infra/errors.js";
+import { normalizeLowercaseStringOrEmpty } from "../../../shared/string-coerce.js";
 import type { EmbeddedContextFile } from "../../pi-embedded-helpers.js";
 import type { MessagingToolSend } from "../../pi-embedded-messaging.js";
 import type { WorkspaceBootstrapFile } from "../../workspace.js";
@@ -391,7 +392,7 @@ vi.mock("../../../image-generation/runtime.js", () => ({
 }));
 
 vi.mock("../../model-selection.js", () => ({
-  normalizeProviderId: (providerId?: string) => providerId?.trim().toLowerCase() ?? "",
+  normalizeProviderId: (providerId?: string) => normalizeLowercaseStringOrEmpty(providerId),
   resolveDefaultModelForAgent: () => ({ provider: "openai", model: "gpt-test" }),
 }));
 
diff --git a/src/agents/test-helpers/fast-openclaw-tools-sessions.ts b/src/agents/test-helpers/fast-openclaw-tools-sessions.ts
index 4d27b8fcb17..039b29bb524 100644
--- a/src/agents/test-helpers/fast-openclaw-tools-sessions.ts
+++ b/src/agents/test-helpers/fast-openclaw-tools-sessions.ts
@@ -1,4 +1,5 @@
 import { vi } from "vitest";
+import { normalizeOptionalLowercaseString } from "../../shared/string-coerce.js";
 import { stubTool } from "./fast-tool-stubs.js";
 
 // Sessions-tool tests only exercise sessions/subagent registrations.
@@ -45,7 +46,7 @@ vi.mock("../tools/update-plan-tool.js", () => ({
 
 vi.mock("../../channels/plugins/index.js", () => ({
   getChannelPlugin: () => null,
-  normalizeChannelId: (channel?: string) => channel?.trim().toLowerCase() || undefined,
+  normalizeChannelId: (channel?: string) => normalizeOptionalLowercaseString(channel),
   listChannelPlugins: () => [],
 }));
 
diff --git a/src/auto-reply/reply.directive.directive-behavior.e2e-harness.ts b/src/auto-reply/reply.directive.directive-behavior.e2e-harness.ts
index e3371c92d40..a1fc1161e54 100644
--- a/src/auto-reply/reply.directive.directive-behavior.e2e-harness.ts
+++ b/src/auto-reply/reply.directive.directive-behavior.e2e-harness.ts
@@ -9,6 +9,7 @@ import { createEmptyPluginRegistry } from "../plugins/registry-empty.js";
 import type { PluginProviderRegistration } from "../plugins/registry.js";
 import { resetPluginRuntimeStateForTest, setActivePluginRegistry } from "../plugins/runtime.js";
 import type { ProviderPlugin } from "../plugins/types.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import {
   loadModelCatalogMock,
   runEmbeddedPiAgentMock,
@@ -61,7 +62,8 @@ function createThinkingPolicyProvider(
     id: providerId,
     label: providerId,
     auth: [],
-    supportsXHighThinking: ({ modelId }) => xhighModelIds.includes(modelId.trim().toLowerCase()),
+    supportsXHighThinking: ({ modelId }) =>
+      xhighModelIds.includes(normalizeLowercaseStringOrEmpty(modelId)),
   };
 }
 
diff --git a/src/canvas-host/a2ui/index.html b/src/canvas-host/a2ui/index.html
index 57e767860d4..7e19e30a716 100644
--- a/src/canvas-host/a2ui/index.html
+++ b/src/canvas-host/a2ui/index.html
@@ -6,9 +6,13 @@
     <title>OpenClaw Canvas</title>
     <script>
       (() => {
+        const normalizeLower = (value) => {
+          const trimmed = String(value || "").trim();
+          return trimmed.toLowerCase();
+        };
         try {
           const params = new URLSearchParams(window.location.search);
-          const platform = (params.get("platform") || "").trim().toLowerCase();
+          const platform = normalizeLower(params.get("platform"));
           if (platform) {
             document.documentElement.dataset.platform = platform;
             return;
@@ -246,7 +250,7 @@
             const params = new URLSearchParams(window.location.search);
             const raw = params.get("debugStatus") ?? params.get("debug");
             if (!raw) return false;
-            const normalized = String(raw).trim().toLowerCase();
+            const normalized = normalizeLower(raw);
             return normalized === "1" || normalized === "true" || normalized === "yes";
           } catch (_) {
             return false;
diff --git a/src/commands/doctor.e2e-harness.ts b/src/commands/doctor.e2e-harness.ts
index a13b8f01ed1..378d690529d 100644
--- a/src/commands/doctor.e2e-harness.ts
+++ b/src/commands/doctor.e2e-harness.ts
@@ -3,6 +3,7 @@ import os from "node:os";
 import path from "node:path";
 import { afterEach, beforeEach, vi } from "vitest";
 import { createEmptyPluginRegistry } from "../plugins/registry-empty.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import type { MockFn } from "../test-utils/vitest-mock-fn.js";
 import {
   readEmbeddedGatewayTokenForTest,
@@ -307,7 +308,7 @@ vi.mock("openclaw/plugin-sdk/provider-auth", () => ({
 
 vi.mock("openclaw/plugin-sdk/provider-model-shared", () => ({
   DEFAULT_CONTEXT_TOKENS: 32768,
-  normalizeProviderId: (value: string) => value.trim().toLowerCase(),
+  normalizeProviderId: (value: string) => normalizeLowercaseStringOrEmpty(value),
 }));
 
 vi.mock("openclaw/plugin-sdk/provider-stream-shared", () => ({
diff --git a/src/infra/outbound/outbound-session.test-helpers.ts b/src/infra/outbound/outbound-session.test-helpers.ts
index 0db1ca6d0af..021317228f6 100644
--- a/src/infra/outbound/outbound-session.test-helpers.ts
+++ b/src/infra/outbound/outbound-session.test-helpers.ts
@@ -13,6 +13,10 @@ import {
   type RoutePeer,
 } from "../../plugin-sdk/routing.js";
 import { setActivePluginRegistry } from "../../plugins/runtime.js";
+import {
+  normalizeLowercaseStringOrEmpty,
+  normalizeOptionalLowercaseString,
+} from "../../shared/string-coerce.js";
 import {
   createChannelTestPluginBase,
   createTestRegistry,
@@ -180,7 +184,7 @@ function resolveSlackOutboundSessionRouteForTest(params: ChannelOutboundSessionR
   const isGroupChannel =
     /^g/i.test(rawId) &&
     params.cfg.channels?.slack?.dm?.groupChannels?.some(
-      (candidate) => String(candidate).trim().toLowerCase() === normalizedId,
+      (candidate) => normalizeLowercaseStringOrEmpty(String(candidate)) === normalizedId,
     ) === true;
   const peerKind: RoutePeer["kind"] = isDm ? "direct" : isGroupChannel ? "group" : "channel";
   return buildThreadedChannelRoute({
@@ -266,7 +270,9 @@ function resolveMattermostOutboundSessionRouteForTest(params: ChannelOutboundSes
 }
 
 function resolveWhatsAppOutboundSessionRouteForTest(params: ChannelOutboundSessionRouteParams) {
-  const normalized = stripChannelTargetPrefix(params.target, "whatsapp").trim().toLowerCase();
+  const normalized = normalizeOptionalLowercaseString(
+    stripChannelTargetPrefix(params.target, "whatsapp"),
+  );
   if (!normalized) {
     return null;
   }