diff --git a/src/plugins/bundled-plugin-scan.ts b/src/plugins/bundled-plugin-scan.ts
index 40d00f1f3c3..43538284be4 100644
--- a/src/plugins/bundled-plugin-scan.ts
+++ b/src/plugins/bundled-plugin-scan.ts
@@ -1,5 +1,7 @@
 import fs from "node:fs";
 import path from "node:path";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
+import { normalizeTrimmedStringList } from "../shared/string-normalization.js";
 
 const PUBLIC_SURFACE_SOURCE_EXTENSIONS = [".ts", ".mts", ".js", ".mjs", ".cts", ".cjs"] as const;
 const RUNTIME_SIDECAR_ARTIFACTS = new Set([
@@ -10,17 +12,11 @@ const RUNTIME_SIDECAR_ARTIFACTS = new Set([
 ]);
 
 export function trimBundledPluginString(value: unknown): string | undefined {
-  return typeof value === "string" && value.trim().length > 0 ? value.trim() : undefined;
+  return normalizeOptionalString(value);
 }
 
 export function normalizeBundledPluginStringList(value: unknown): string[] {
-  if (!Array.isArray(value)) {
-    return [];
-  }
-  return value.flatMap((entry) => {
-    const normalized = trimBundledPluginString(entry);
-    return normalized ? [normalized] : [];
-  });
+  return normalizeTrimmedStringList(value);
 }
 
 export function rewriteBundledPluginEntryToBuiltPath(
@@ -79,9 +75,9 @@ export function collectBundledPluginPublicSurfaceArtifacts(params: {
   setupEntry?: string;
 }): readonly string[] | undefined {
   const excluded = new Set(
-    [params.sourceEntry, params.setupEntry]
-      .filter((entry): entry is string => typeof entry === "string" && entry.trim().length > 0)
-      .map((entry) => path.basename(entry)),
+    normalizeTrimmedStringList([params.sourceEntry, params.setupEntry]).map((entry) =>
+      path.basename(entry),
+    ),
   );
   const artifacts = fs
     .readdirSync(params.pluginDir, { withFileTypes: true })
diff --git a/src/plugins/cache-controls.ts b/src/plugins/cache-controls.ts
index 8b613516d80..6ece26892e0 100644
--- a/src/plugins/cache-controls.ts
+++ b/src/plugins/cache-controls.ts
@@ -1,18 +1,20 @@
+import { normalizeOptionalString } from "../shared/string-coerce.js";
+
 export const DEFAULT_PLUGIN_DISCOVERY_CACHE_MS = 1000;
 export const DEFAULT_PLUGIN_MANIFEST_CACHE_MS = 1000;
 
 export function shouldUsePluginSnapshotCache(env: NodeJS.ProcessEnv): boolean {
-  if (env.OPENCLAW_DISABLE_PLUGIN_DISCOVERY_CACHE?.trim()) {
+  if (normalizeOptionalString(env.OPENCLAW_DISABLE_PLUGIN_DISCOVERY_CACHE)) {
     return false;
   }
-  if (env.OPENCLAW_DISABLE_PLUGIN_MANIFEST_CACHE?.trim()) {
+  if (normalizeOptionalString(env.OPENCLAW_DISABLE_PLUGIN_MANIFEST_CACHE)) {
     return false;
   }
-  const discoveryCacheMs = env.OPENCLAW_PLUGIN_DISCOVERY_CACHE_MS?.trim();
+  const discoveryCacheMs = normalizeOptionalString(env.OPENCLAW_PLUGIN_DISCOVERY_CACHE_MS);
   if (discoveryCacheMs === "0") {
     return false;
   }
-  const manifestCacheMs = env.OPENCLAW_PLUGIN_MANIFEST_CACHE_MS?.trim();
+  const manifestCacheMs = normalizeOptionalString(env.OPENCLAW_PLUGIN_MANIFEST_CACHE_MS);
   if (manifestCacheMs === "0") {
     return false;
   }
@@ -20,7 +22,7 @@ export function shouldUsePluginSnapshotCache(env: NodeJS.ProcessEnv): boolean {
 }
 
 export function resolvePluginCacheMs(rawValue: string | undefined, defaultMs: number): number {
-  const raw = rawValue?.trim();
+  const raw = normalizeOptionalString(rawValue);
   if (raw === "" || raw === "0") {
     return 0;
   }
diff --git a/src/plugins/http-path.ts b/src/plugins/http-path.ts
index 069b5ff8d92..d4afb692fed 100644
--- a/src/plugins/http-path.ts
+++ b/src/plugins/http-path.ts
@@ -1,10 +1,12 @@
+import { normalizeOptionalString } from "../shared/string-coerce.js";
+
 export function normalizePluginHttpPath(
   path?: string | null,
   fallback?: string | null,
 ): string | null {
-  const trimmed = path?.trim();
+  const trimmed = normalizeOptionalString(path);
   if (!trimmed) {
-    const fallbackTrimmed = fallback?.trim();
+    const fallbackTrimmed = normalizeOptionalString(fallback);
     if (!fallbackTrimmed) {
       return null;
     }
diff --git a/src/plugins/provider-auth-choice-helpers.ts b/src/plugins/provider-auth-choice-helpers.ts
index c47fe9bb84d..c450f401f21 100644
--- a/src/plugins/provider-auth-choice-helpers.ts
+++ b/src/plugins/provider-auth-choice-helpers.ts
@@ -1,12 +1,13 @@
 import { normalizeProviderId } from "../agents/model-selection.js";
 import type { OpenClawConfig } from "../config/config.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import type { ProviderAuthMethod, ProviderPlugin } from "./types.js";
 
 export function resolveProviderMatch(
   providers: ProviderPlugin[],
   rawProvider?: string,
 ): ProviderPlugin | null {
-  const raw = rawProvider?.trim();
+  const raw = normalizeOptionalString(rawProvider);
   if (!raw) {
     return null;
   }
@@ -25,7 +26,7 @@ export function pickAuthMethod(
   provider: ProviderPlugin,
   rawMethod?: string,
 ): ProviderAuthMethod | null {
-  const raw = rawMethod?.trim();
+  const raw = normalizeOptionalString(rawMethod);
   if (!raw) {
     return null;
   }
diff --git a/src/plugins/provider-registry-shared.ts b/src/plugins/provider-registry-shared.ts
index e840ae9e658..ac8cbc9cd52 100644
--- a/src/plugins/provider-registry-shared.ts
+++ b/src/plugins/provider-registry-shared.ts
@@ -1,5 +1,7 @@
+import { normalizeOptionalString } from "../shared/string-coerce.js";
+
 export function normalizeCapabilityProviderId(providerId: string | undefined): string | undefined {
-  const trimmed = providerId?.trim().toLowerCase();
+  const trimmed = normalizeOptionalString(providerId)?.toLowerCase();
   return trimmed ? trimmed : undefined;
 }
 
diff --git a/src/plugins/provider-validation.ts b/src/plugins/provider-validation.ts
index 32db406f8df..6f3c8c42560 100644
--- a/src/plugins/provider-validation.ts
+++ b/src/plugins/provider-validation.ts
@@ -1,3 +1,5 @@
+import { normalizeOptionalString } from "../shared/string-coerce.js";
+import { normalizeTrimmedStringList } from "../shared/string-normalization.js";
 import type { PluginDiagnostic, ProviderAuthMethod, ProviderPlugin } from "./types.js";
 
 type ProviderWizardSetup = NonNullable<NonNullable<ProviderPlugin["wizard"]>["setup"]>;
@@ -20,14 +22,11 @@ function pushProviderDiagnostic(params: {
 }
 
 function normalizeText(value: string | undefined): string | undefined {
-  const trimmed = value?.trim();
-  return trimmed ? trimmed : undefined;
+  return normalizeOptionalString(value);
 }
 
 function normalizeTextList(values: string[] | undefined): string[] | undefined {
-  const normalized = Array.from(
-    new Set((values ?? []).map((value) => value.trim()).filter(Boolean)),
-  );
+  const normalized = Array.from(new Set(normalizeTrimmedStringList(values)));
   return normalized.length > 0 ? normalized : undefined;
 }