diff --git a/src/agents/tools/web-fetch.ts b/src/agents/tools/web-fetch.ts
index cbdbabfc766..1b98b9928fc 100644
--- a/src/agents/tools/web-fetch.ts
+++ b/src/agents/tools/web-fetch.ts
@@ -4,6 +4,7 @@ import { SsrFBlockedError, type LookupFn } from "../../infra/net/ssrf.js";
 import { logDebug } from "../../logger.js";
 import type { RuntimeWebFetchMetadata } from "../../secrets/runtime-web-tools.types.js";
 import { wrapExternalContent, wrapWebContent } from "../../security/external-content.js";
+import { normalizeOptionalString } from "../../shared/string-coerce.js";
 import { isRecord } from "../../utils.js";
 import { resolveWebFetchDefinition } from "../../web-fetch/runtime.js";
 import { resolveWebProviderConfig } from "../../web/provider-runtime-shared.js";
@@ -247,10 +248,7 @@ type WebFetchRuntimeParams = {
 };
 
 function normalizeProviderFinalUrl(value: unknown): string | undefined {
-  if (typeof value !== "string") {
-    return undefined;
-  }
-  const trimmed = value.trim();
+  const trimmed = normalizeOptionalString(value);
   if (!trimmed) {
     return undefined;
   }
diff --git a/src/cli/message-secret-scope.ts b/src/cli/message-secret-scope.ts
index 5dd72655ec6..a60afb550ef 100644
--- a/src/cli/message-secret-scope.ts
+++ b/src/cli/message-secret-scope.ts
@@ -1,4 +1,5 @@
 import { normalizeAccountId } from "../routing/session-key.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import { isDeliverableMessageChannel, normalizeMessageChannel } from "../utils/message-channel.js";
 
 function resolveScopedChannelCandidate(value: unknown): string | undefined {
@@ -13,10 +14,7 @@ function resolveScopedChannelCandidate(value: unknown): string | undefined {
 }
 
 function resolveChannelFromTargetValue(target: unknown): string | undefined {
-  if (typeof target !== "string") {
-    return undefined;
-  }
-  const trimmed = target.trim();
+  const trimmed = normalizeOptionalString(target);
   if (!trimmed) {
     return undefined;
   }
@@ -45,10 +43,7 @@ function resolveChannelFromTargets(targets: unknown): string | undefined {
 }
 
 function resolveScopedAccountId(value: unknown): string | undefined {
-  if (typeof value !== "string") {
-    return undefined;
-  }
-  const trimmed = value.trim();
+  const trimmed = normalizeOptionalString(value);
   if (!trimmed) {
     return undefined;
   }
diff --git a/src/gateway/server-methods/nodes.helpers.ts b/src/gateway/server-methods/nodes.helpers.ts
index 62703ee3c43..30ab7f02062 100644
--- a/src/gateway/server-methods/nodes.helpers.ts
+++ b/src/gateway/server-methods/nodes.helpers.ts
@@ -1,4 +1,5 @@
 import type { ErrorObject } from "ajv";
+import { normalizeOptionalString } from "../../shared/string-coerce.js";
 import { ErrorCodes, errorShape, formatValidationErrors } from "../protocol/index.js";
 import { formatForLog } from "../ws-log.js";
 import type { RespondFn } from "./types.js";
@@ -38,10 +39,7 @@ export function uniqueSortedStrings(values: unknown[]) {
 }
 
 export function safeParseJson(value: string | null | undefined): unknown {
-  if (typeof value !== "string") {
-    return undefined;
-  }
-  const trimmed = value.trim();
+  const trimmed = normalizeOptionalString(value);
   if (!trimmed) {
     return undefined;
   }
diff --git a/src/infra/scp-host.ts b/src/infra/scp-host.ts
index 8b09163c202..527c2cb3765 100644
--- a/src/infra/scp-host.ts
+++ b/src/infra/scp-host.ts
@@ -1,3 +1,5 @@
+import { normalizeOptionalString } from "../shared/string-coerce.js";
+
 const SSH_TOKEN = /^[A-Za-z0-9._-]+$/;
 const BRACKETED_IPV6 = /^\[[0-9A-Fa-f:.%]+\]$/;
 const WHITESPACE = /\s/;
@@ -14,10 +16,7 @@ function hasControlOrWhitespace(value: string): boolean {
 }
 
 export function normalizeScpRemoteHost(value: string | null | undefined): string | undefined {
-  if (typeof value !== "string") {
-    return undefined;
-  }
-  const trimmed = value.trim();
+  const trimmed = normalizeOptionalString(value);
   if (!trimmed) {
     return undefined;
   }
@@ -63,10 +62,7 @@ export function isSafeScpRemoteHost(value: string | null | undefined): boolean {
 }
 
 export function normalizeScpRemotePath(value: string | null | undefined): string | undefined {
-  if (typeof value !== "string") {
-    return undefined;
-  }
-  const trimmed = value.trim();
+  const trimmed = normalizeOptionalString(value);
   if (!trimmed || !trimmed.startsWith("/")) {
     return undefined;
   }
diff --git a/src/plugins/config-normalization-shared.ts b/src/plugins/config-normalization-shared.ts
index b9708378013..b2f8ac26056 100644
--- a/src/plugins/config-normalization-shared.ts
+++ b/src/plugins/config-normalization-shared.ts
@@ -1,5 +1,6 @@
 import { normalizeChatChannelId } from "../channels/ids.js";
 import type { OpenClawConfig } from "../config/config.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import { defaultSlotIdForKey } from "./slots.js";
 
 export type NormalizedPluginsConfig = {
@@ -41,10 +42,7 @@ function normalizeList(value: unknown, normalizePluginId: NormalizePluginId): st
 }
 
 function normalizeSlotValue(value: unknown): string | null | undefined {
-  if (typeof value !== "string") {
-    return undefined;
-  }
-  const trimmed = value.trim();
+  const trimmed = normalizeOptionalString(value);
   if (!trimmed) {
     return undefined;
   }
@@ -97,8 +95,8 @@ function normalizePluginEntries(
             ),
             allowedModels: Array.isArray((subagentRaw as { allowedModels?: unknown }).allowedModels)
               ? ((subagentRaw as { allowedModels?: unknown }).allowedModels as unknown[])
-                  .map((model) => (typeof model === "string" ? model.trim() : ""))
-                  .filter(Boolean)
+                  .map((model) => normalizeOptionalString(model))
+                  .filter((model): model is string => Boolean(model))
               : undefined,
           }
         : undefined;
diff --git a/src/shared/assistant-identity-values.ts b/src/shared/assistant-identity-values.ts
index 8894ee129d3..f21e507c902 100644
--- a/src/shared/assistant-identity-values.ts
+++ b/src/shared/assistant-identity-values.ts
@@ -1,11 +1,10 @@
+import { normalizeOptionalString } from "./string-coerce.js";
+
 export function coerceIdentityValue(
   value: string | undefined,
   maxLength: number,
 ): string | undefined {
-  if (typeof value !== "string") {
-    return undefined;
-  }
-  const trimmed = value.trim();
+  const trimmed = normalizeOptionalString(value);
   if (!trimmed) {
     return undefined;
   }