diff --git a/src/flows/model-picker.ts b/src/flows/model-picker.ts
index cd0ab1f85d..d6a66b770a 100644
--- a/src/flows/model-picker.ts
+++ b/src/flows/model-picker.ts
@@ -17,6 +17,7 @@ import { resolveOwningPluginIdsForProvider } from "../plugins/providers.js";
 import type { ProviderPlugin } from "../plugins/types.js";
 import type { RuntimeEnv } from "../runtime.js";
 import { createLazyRuntimeSurface } from "../shared/lazy-runtime.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import type { WizardPrompter, WizardSelectOption } from "../wizard/prompts.js";
 
 export { applyPrimaryModel } from "../plugins/provider-model-primary.js";
@@ -221,7 +222,9 @@ async function promptManualModel(params: {
     message: params.allowBlank ? "Default model (blank to keep)" : "Default model",
     initialValue: params.initialValue,
     placeholder: "provider/model",
-    validate: params.allowBlank ? undefined : (value) => (value?.trim() ? undefined : "Required"),
+    validate: params.allowBlank
+      ? undefined
+      : (value) => (normalizeOptionalString(value) ? undefined : "Required"),
   });
   const model = String(modelInput ?? "").trim();
   if (!model) {
@@ -410,7 +413,7 @@ export async function promptDefaultModel(
   const includeManual = params.includeManual ?? true;
   const includeProviderPluginSetups = params.includeProviderPluginSetups ?? false;
   const ignoreAllowlist = params.ignoreAllowlist ?? false;
-  const preferredProvider = params.preferredProvider?.trim()
+  const preferredProvider = normalizeOptionalString(params.preferredProvider)
     ? normalizeProviderId(params.preferredProvider)
     : undefined;
   const configuredRaw = resolveConfiguredModelRaw(cfg);
@@ -578,7 +581,7 @@ export async function promptModelAllowlist(params: {
   const existingKeys = resolveConfiguredModelKeys(cfg);
   const allowedKeys = normalizeModelKeys(params.allowedKeys ?? []);
   const allowedKeySet = allowedKeys.length > 0 ? new Set(allowedKeys) : null;
-  const preferredProvider = params.preferredProvider?.trim()
+  const preferredProvider = normalizeOptionalString(params.preferredProvider)
     ? normalizeProviderId(params.preferredProvider)
     : undefined;
   const resolved = resolveConfiguredModelRef({
diff --git a/src/flows/provider-flow.ts b/src/flows/provider-flow.ts
index 62612457b8..93c6924ee2 100644
--- a/src/flows/provider-flow.ts
+++ b/src/flows/provider-flow.ts
@@ -5,6 +5,7 @@ import {
 } from "../plugins/provider-wizard.js";
 import { resolvePluginProviders } from "../plugins/providers.runtime.js";
 import type { ProviderPlugin } from "../plugins/types.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import type { FlowContribution, FlowOption } from "./types.js";
 import { sortFlowContributionsByLabel } from "./types.js";
 
@@ -56,9 +57,9 @@ function resolveProviderDocsById(params?: {
       mode: "setup",
     })
       .filter((provider): provider is ProviderPlugin & { docsPath: string } =>
-        Boolean(provider.docsPath?.trim()),
+        Boolean(normalizeOptionalString(provider.docsPath)),
       )
-      .map((provider) => [provider.id, provider.docsPath.trim()]),
+      .map((provider) => [provider.id, normalizeOptionalString(provider.docsPath)!]),
   );
 }
 
diff --git a/src/flows/search-setup.ts b/src/flows/search-setup.ts
index c354ec6066..27f9378952 100644
--- a/src/flows/search-setup.ts
+++ b/src/flows/search-setup.ts
@@ -12,6 +12,7 @@ import type { PluginWebSearchProviderEntry } from "../plugins/types.js";
 import { resolvePluginWebSearchProviders } from "../plugins/web-search-providers.runtime.js";
 import { sortWebSearchProviders } from "../plugins/web-search-providers.shared.js";
 import type { RuntimeEnv } from "../runtime.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import type { WizardPrompter } from "../wizard/prompts.js";
 import type { FlowContribution, FlowOption } from "./types.js";
 import { sortFlowContributionsByLabel } from "./types.js";
@@ -40,7 +41,7 @@ function resolveSearchProviderCredentialLabel(
   if (entry.requiresCredential === false) {
     return `${entry.label} setup`;
   }
-  return entry.credentialLabel?.trim() || `${entry.label} API key`;
+  return normalizeOptionalString(entry.credentialLabel) || `${entry.label} API key`;
 }
 
 export function listSearchProviderOptions(
@@ -107,7 +108,7 @@ function resolveSearchProviderEntry(
 }
 
 export function hasKeyInEnv(entry: Pick<PluginWebSearchProviderEntry, "envVars">): boolean {
-  return entry.envVars.some((k) => Boolean(process.env[k]?.trim()));
+  return entry.envVars.some((k) => Boolean(normalizeOptionalString(process.env[k])));
 }
 
 function providerNeedsCredential(
@@ -154,13 +155,15 @@ function buildSearchEnvRef(config: OpenClawConfig, provider: SearchProvider): Se
     resolveSearchProviderEntry(config, provider) ??
     listSearchProviderOptions(config).find((candidate) => candidate.id === provider) ??
     listSearchProviderOptions().find((candidate) => candidate.id === provider);
-  const envVar = entry?.envVars.find((k) => Boolean(process.env[k]?.trim())) ?? entry?.envVars[0];
-  if (!envVar) {
+  const resolvedEnvVar =
+    entry?.envVars.find((k) => Boolean(normalizeOptionalString(process.env[k]))) ??
+    entry?.envVars[0];
+  if (!resolvedEnvVar) {
     throw new Error(
       `No env var mapping for search provider "${provider}" at ${entry?.credentialPath ?? "unknown path"} in secret-input-mode=ref.`,
     );
   }
-  return { source: "env", provider: DEFAULT_SECRET_PROVIDER_ALIAS, id: envVar };
+  return { source: "env", provider: DEFAULT_SECRET_PROVIDER_ALIAS, id: resolvedEnvVar };
 }
 
 function resolveSearchSecretInput(
@@ -478,7 +481,7 @@ export async function runSearchSetupFlow(
     placeholder: keyConfigured ? "Leave blank to keep current" : entry.placeholder,
   });
 
-  const key = keyInput?.trim() ?? "";
+  const key = normalizeOptionalString(keyInput) ?? "";
   if (key) {
     const secretInput = resolveSearchSecretInput(config, choice, key, opts?.secretInputMode);
     return await finalizeSearchProviderSetup({
diff --git a/src/plugins/provider-auth-ref.ts b/src/plugins/provider-auth-ref.ts
index 15ea0631c1..167b7d4a42 100644
--- a/src/plugins/provider-auth-ref.ts
+++ b/src/plugins/provider-auth-ref.ts
@@ -9,6 +9,7 @@ import {
   isValidFileSecretRefId,
   resolveDefaultSecretProviderAlias,
 } from "../secrets/ref-contract.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import type { WizardPrompter } from "../wizard/prompts.js";
 
 let secretResolvePromise: Promise<typeof import("../secrets/resolve.js")> | undefined;
@@ -40,7 +41,7 @@ export function extractEnvVarFromSourceLabel(source: string): string | undefined
 
 function resolveDefaultProviderEnvVar(provider: string): string | undefined {
   const envVars = getProviderEnvVars(provider);
-  return envVars?.find((candidate) => candidate.trim().length > 0);
+  return envVars?.find((candidate) => normalizeOptionalString(candidate) !== undefined);
 }
 
 function resolveDefaultFilePointerId(provider: string): string {
@@ -60,7 +61,7 @@ export function resolveRefFallbackInput(params: {
     );
   }
   const env = params.env ?? process.env;
-  const value = env[fallbackEnvVar]?.trim();
+  const value = normalizeOptionalString(env[fallbackEnvVar]);
   if (!value) {
     throw new Error(
       `Environment variable "${fallbackEnvVar}" is required for --secret-input-mode ref in non-interactive setup.`,
@@ -99,7 +100,7 @@ async function promptEnvSecretRefForSetup(params: {
           'Use an env var name like "OPENAI_API_KEY" (uppercase letters, numbers, underscores).'
         );
       }
-      if (!env[candidate]?.trim()) {
+      if (!normalizeOptionalString(env[candidate])) {
         return (
           params.copy?.envVarMissingError?.(candidate) ??
           `Environment variable "${candidate}" is missing or empty in this session.`
@@ -116,7 +117,7 @@ async function promptEnvSecretRefForSetup(params: {
       `No valid environment variable name provided for provider "${params.provider}".`,
     );
   }
-  const resolvedValue = env[envVar]?.trim();
+  const resolvedValue = normalizeOptionalString(env[envVar]);
   if (!resolvedValue) {
     throw new Error(`Environment variable "${envVar}" is missing or empty in this session.`);
   }
diff --git a/src/plugins/provider-wizard.ts b/src/plugins/provider-wizard.ts
index ffa608acb1..00cbd13d26 100644
--- a/src/plugins/provider-wizard.ts
+++ b/src/plugins/provider-wizard.ts
@@ -1,6 +1,7 @@
 import { DEFAULT_PROVIDER } from "../agents/defaults.js";
 import { normalizeProviderId } from "../agents/model-selection.js";
 import type { OpenClawConfig } from "../config/config.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import type { WizardPrompter } from "../wizard/prompts.js";
 import { resolvePluginProviders } from "./providers.runtime.js";
 import type {
@@ -31,18 +32,18 @@ export type ProviderModelPickerEntry = {
 };
 
 function normalizeChoiceId(choiceId: string): string {
-  return choiceId.trim();
+  return normalizeOptionalString(choiceId) ?? "";
 }
 
 function resolveWizardSetupChoiceId(
   provider: ProviderPlugin,
   wizard: ProviderPluginWizardSetup,
 ): string {
-  const explicit = wizard.choiceId?.trim();
+  const explicit = normalizeOptionalString(wizard.choiceId);
   if (explicit) {
     return explicit;
   }
-  const explicitMethodId = wizard.methodId?.trim();
+  const explicitMethodId = normalizeOptionalString(wizard.methodId);
   if (explicitMethodId) {
     return buildProviderPluginMethodChoice(provider.id, explicitMethodId);
   }
@@ -56,11 +57,13 @@ function resolveMethodById(
   provider: ProviderPlugin,
   methodId?: string,
 ): ProviderAuthMethod | undefined {
-  const normalizedMethodId = methodId?.trim().toLowerCase();
+  const normalizedMethodId = normalizeOptionalString(methodId)?.toLowerCase();
   if (!normalizedMethodId) {
     return provider.auth[0];
   }
-  return provider.auth.find((method) => method.id.trim().toLowerCase() === normalizedMethodId);
+  return provider.auth.find(
+    (method) => normalizeOptionalString(method.id)?.toLowerCase() === normalizedMethodId,
+  );
 }
 
 function listMethodWizardSetups(provider: ProviderPlugin): Array<{
@@ -80,16 +83,16 @@ function buildSetupOptionForMethod(params: {
   method: ProviderAuthMethod;
   value: string;
 }): ProviderWizardOption {
-  const normalizedGroupId = params.wizard.groupId?.trim() || params.provider.id;
+  const normalizedGroupId = normalizeOptionalString(params.wizard.groupId) || params.provider.id;
   return {
     value: normalizeChoiceId(params.value),
     label:
-      params.wizard.choiceLabel?.trim() ||
+      normalizeOptionalString(params.wizard.choiceLabel) ||
       (params.provider.auth.length === 1 ? params.provider.label : params.method.label),
-    hint: params.wizard.choiceHint?.trim() || params.method.hint,
+    hint: normalizeOptionalString(params.wizard.choiceHint) || params.method.hint,
     groupId: normalizedGroupId,
-    groupLabel: params.wizard.groupLabel?.trim() || params.provider.label,
-    groupHint: params.wizard.groupHint?.trim(),
+    groupLabel: normalizeOptionalString(params.wizard.groupLabel) || params.provider.label,
+    groupHint: normalizeOptionalString(params.wizard.groupHint),
     ...(params.wizard.onboardingScopes ? { onboardingScopes: params.wizard.onboardingScopes } : {}),
     ...(typeof params.wizard.assistantPriority === "number" &&
     Number.isFinite(params.wizard.assistantPriority)
@@ -102,7 +105,7 @@ function buildSetupOptionForMethod(params: {
 }
 
 export function buildProviderPluginMethodChoice(providerId: string, methodId: string): string {
-  return `${PROVIDER_PLUGIN_CHOICE_PREFIX}${providerId.trim()}:${methodId.trim()}`;
+  return `${PROVIDER_PLUGIN_CHOICE_PREFIX}${normalizeChoiceId(providerId)}:${normalizeChoiceId(methodId)}`;
 }
 
 function resolveProviderWizardProviders(params: {
@@ -134,7 +137,9 @@ export function resolveProviderWizardOptions(params: {
           provider,
           wizard,
           method,
-          value: wizard.choiceId?.trim() || buildProviderPluginMethodChoice(provider.id, method.id),
+          value:
+            normalizeOptionalString(wizard.choiceId) ||
+            buildProviderPluginMethodChoice(provider.id, method.id),
         }),
       );
     }
@@ -177,7 +182,7 @@ function resolveModelPickerChoiceValue(
   provider: ProviderPlugin,
   modelPicker: ProviderPluginWizardModelPicker,
 ): string {
-  const explicitMethodId = modelPicker.methodId?.trim();
+  const explicitMethodId = normalizeOptionalString(modelPicker.methodId);
   if (explicitMethodId) {
     return buildProviderPluginMethodChoice(provider.id, explicitMethodId);
   }
@@ -202,8 +207,8 @@ export function resolveProviderModelPickerEntries(params: {
     }
     entries.push({
       value: resolveModelPickerChoiceValue(provider, modelPicker),
-      label: modelPicker.label?.trim() || `${provider.label} (custom)`,
-      hint: modelPicker.hint?.trim(),
+      label: normalizeOptionalString(modelPicker.label) || `${provider.label} (custom)`,
+      hint: normalizeOptionalString(modelPicker.hint),
     });
   }
 
@@ -218,7 +223,7 @@ export function resolveProviderPluginChoice(params: {
   method: ProviderAuthMethod;
   wizard?: ProviderPluginWizardSetup;
 } | null {
-  const choice = params.choice.trim();
+  const choice = normalizeChoiceId(params.choice);
   if (!choice) {
     return null;
   }
@@ -241,7 +246,8 @@ export function resolveProviderPluginChoice(params: {
   for (const provider of params.providers) {
     for (const { method, wizard } of listMethodWizardSetups(provider)) {
       const choiceId =
-        wizard.choiceId?.trim() || buildProviderPluginMethodChoice(provider.id, method.id);
+        normalizeOptionalString(wizard.choiceId) ||
+        buildProviderPluginMethodChoice(provider.id, method.id);
       if (normalizeChoiceId(choiceId) === choice) {
         return { provider, method, wizard };
       }
diff --git a/src/utils/provider-utils.ts b/src/utils/provider-utils.ts
index 4860563915..b700059e55 100644
--- a/src/utils/provider-utils.ts
+++ b/src/utils/provider-utils.ts
@@ -1,6 +1,7 @@
 import type { OpenClawConfig } from "../config/config.js";
 import { resolveProviderReasoningOutputModeWithPlugin } from "../plugins/provider-runtime.js";
 import type { ProviderRuntimeModel } from "../plugins/types.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 
 const BUILTIN_REASONING_OUTPUT_MODES = {
   "google-generative-ai": "tagged",
@@ -19,7 +20,7 @@ export function resolveReasoningOutputMode(params: {
   modelApi?: string | null;
   model?: ProviderRuntimeModel;
 }): "native" | "tagged" {
-  const provider = params.provider?.trim();
+  const provider = normalizeOptionalString(params.provider);
   if (!provider) {
     return "native";
   }
diff --git a/src/utils/usage-format.ts b/src/utils/usage-format.ts
index b32717c37b..2c1c9de2bb 100644
--- a/src/utils/usage-format.ts
+++ b/src/utils/usage-format.ts
@@ -6,6 +6,7 @@ import type { NormalizedUsage } from "../agents/usage.js";
 import type { OpenClawConfig } from "../config/config.js";
 import type { ModelProviderConfig } from "../config/types.models.js";
 import { getCachedGatewayModelPricing } from "../gateway/model-pricing-cache.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 
 export type ModelCostConfig = {
   input: number;
@@ -69,8 +70,8 @@ function toResolvedModelKey(params: {
   model?: string;
   allowPluginNormalization?: boolean;
 }): string | null {
-  const provider = params.provider?.trim();
-  const model = params.model?.trim();
+  const provider = normalizeOptionalString(params.provider);
+  const model = normalizeOptionalString(params.model);
   if (!provider || !model) {
     return null;
   }
@@ -81,8 +82,8 @@ function toResolvedModelKey(params: {
 }
 
 function toDirectModelKey(params: { provider?: string; model?: string }): string | null {
-  const provider = normalizeProviderId(params.provider?.trim() ?? "");
-  const model = params.model?.trim();
+  const provider = normalizeProviderId(normalizeOptionalString(params.provider) ?? "");
+  const model = normalizeOptionalString(params.model);
   if (!provider || !model) {
     return null;
   }
@@ -90,8 +91,8 @@ function toDirectModelKey(params: { provider?: string; model?: string }): string
 }
 
 function shouldUseNormalizedCostLookup(params: { provider?: string; model?: string }): boolean {
-  const provider = normalizeProviderId(params.provider?.trim() ?? "");
-  const model = params.model?.trim() ?? "";
+  const provider = normalizeProviderId(normalizeOptionalString(params.provider) ?? "");
+  const model = normalizeOptionalString(params.model) ?? "";
   if (!provider || !model) {
     return false;
   }