diff --git a/src/agents/context.ts b/src/agents/context.ts
index 3404c90093..176e0ef20b 100644
--- a/src/agents/context.ts
+++ b/src/agents/context.ts
@@ -6,6 +6,7 @@ import { loadConfig } from "../config/config.js";
 import type { OpenClawConfig } from "../config/config.js";
 import { computeBackoff, type BackoffPolicy } from "../infra/backoff.js";
 import { consumeRootOptionToken, FLAG_TERMINATOR } from "../infra/cli-root-options.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { resolveOpenClawAgentDir } from "./agent-paths.js";
 import { lookupCachedContextTokens, MODEL_CONTEXT_TOKEN_CACHE } from "./context-cache.js";
 import { CONTEXT_WINDOW_RUNTIME_STATE } from "./context-runtime-state.js";
@@ -92,10 +93,7 @@ function loadModelsConfigRuntime() {
 }
 
 function isLikelyOpenClawCliProcess(argv: string[] = process.argv): boolean {
-  const entryBasename = path
-    .basename(argv[1] ?? "")
-    .trim()
-    .toLowerCase();
+  const entryBasename = normalizeLowercaseStringOrEmpty(path.basename(argv[1] ?? ""));
   return (
     entryBasename === "openclaw" ||
     entryBasename === "openclaw.mjs" ||
@@ -275,9 +273,9 @@ function resolveConfiguredModelParams(
   if (!models) {
     return undefined;
   }
-  const key = `${provider}/${model}`.trim().toLowerCase();
+  const key = normalizeLowercaseStringOrEmpty(`${provider}/${model}`);
   for (const [rawKey, entry] of Object.entries(models)) {
-    if (rawKey.trim().toLowerCase() === key) {
+    if (normalizeLowercaseStringOrEmpty(rawKey) === key) {
       const params = (entry as AgentModelEntry | undefined)?.params;
       return params && typeof params === "object" ? params : undefined;
     }
@@ -360,7 +358,9 @@ function resolveConfiguredProviderContextTokens(
   }
 
   // 1. Exact match (case-insensitive, no alias expansion).
-  const exactResult = findContextTokens((id) => id.trim().toLowerCase() === provider.toLowerCase());
+  const exactResult = findContextTokens(
+    (id) => normalizeLowercaseStringOrEmpty(id) === normalizeLowercaseStringOrEmpty(provider),
+  );
   if (exactResult !== undefined) {
     return exactResult;
   }
@@ -374,7 +374,7 @@ function isAnthropic1MModel(provider: string, model: string): boolean {
   if (provider !== "anthropic") {
     return false;
   }
-  const normalized = model.trim().toLowerCase();
+  const normalized = normalizeLowercaseStringOrEmpty(model);
   const modelId = normalized.includes("/")
     ? (normalized.split("/").at(-1) ?? normalized)
     : normalized;
diff --git a/src/agents/model-catalog.ts b/src/agents/model-catalog.ts
index 92e8f2e7db..0161596190 100644
--- a/src/agents/model-catalog.ts
+++ b/src/agents/model-catalog.ts
@@ -1,6 +1,7 @@
 import { type OpenClawConfig, loadConfig } from "../config/config.js";
 import { createSubsystemLogger } from "../logging/subsystem.js";
 import { augmentModelCatalogWithProviderPlugins } from "../plugins/provider-runtime.runtime.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { resolveOpenClawAgentDir } from "./agent-paths.js";
 import { ensureOpenClawModelsJson } from "./models-config.js";
 import { normalizeProviderId } from "./provider-id.js";
@@ -164,11 +165,12 @@ export async function loadModelCatalog(params?: {
       if (supplemental.length > 0) {
         const seen = new Set(
           models.map(
-            (entry) => `${entry.provider.toLowerCase().trim()}::${entry.id.toLowerCase().trim()}`,
+            (entry) =>
+              `${normalizeLowercaseStringOrEmpty(entry.provider)}::${normalizeLowercaseStringOrEmpty(entry.id)}`,
           ),
         );
         for (const entry of supplemental) {
-          const key = `${entry.provider.toLowerCase().trim()}::${entry.id.toLowerCase().trim()}`;
+          const key = `${normalizeLowercaseStringOrEmpty(entry.provider)}::${normalizeLowercaseStringOrEmpty(entry.id)}`;
           if (seen.has(key)) {
             continue;
           }
@@ -226,10 +228,10 @@ export function findModelInCatalog(
   modelId: string,
 ): ModelCatalogEntry | undefined {
   const normalizedProvider = normalizeProviderId(provider);
-  const normalizedModelId = modelId.toLowerCase().trim();
+  const normalizedModelId = normalizeLowercaseStringOrEmpty(modelId);
   return catalog.find(
     (entry) =>
       normalizeProviderId(entry.provider) === normalizedProvider &&
-      entry.id.toLowerCase() === normalizedModelId,
+      normalizeLowercaseStringOrEmpty(entry.id) === normalizedModelId,
   );
 }
diff --git a/src/agents/pi-embedded-runner/anthropic-family-cache-semantics.ts b/src/agents/pi-embedded-runner/anthropic-family-cache-semantics.ts
index 2e5d38d242..686babfef0 100644
--- a/src/agents/pi-embedded-runner/anthropic-family-cache-semantics.ts
+++ b/src/agents/pi-embedded-runner/anthropic-family-cache-semantics.ts
@@ -1,17 +1,22 @@
+import {
+  normalizeLowercaseStringOrEmpty,
+  normalizeOptionalLowercaseString,
+} from "../../shared/string-coerce.js";
+
 type AnthropicCacheRetentionFamily =
   | "anthropic-direct"
   | "anthropic-bedrock"
   | "custom-anthropic-api";
 
 export function isAnthropicModelRef(modelId: string): boolean {
-  return modelId.trim().toLowerCase().startsWith("anthropic/");
+  return normalizeLowercaseStringOrEmpty(modelId).startsWith("anthropic/");
 }
 
 /** Matches Application Inference Profile ARNs across all AWS partitions with Bedrock. */
 const BEDROCK_APP_INFERENCE_PROFILE_ARN_RE = /^arn:aws(-cn|-us-gov)?:bedrock:/;
 
 export function isAnthropicBedrockModel(modelId: string): boolean {
-  const normalized = modelId.trim().toLowerCase();
+  const normalized = normalizeLowercaseStringOrEmpty(modelId);
 
   // Direct Anthropic Claude model IDs and regional inference profiles
   // e.g. "anthropic.claude-sonnet-4-6", "us.anthropic.claude-sonnet-4-6", "global.anthropic.claude-opus-4-6-v1"
@@ -41,7 +46,9 @@ export function isAnthropicBedrockModel(modelId: string): boolean {
 }
 
 export function isOpenRouterAnthropicModelRef(provider: string, modelId: string): boolean {
-  return provider.trim().toLowerCase() === "openrouter" && isAnthropicModelRef(modelId);
+  return (
+    normalizeOptionalLowercaseString(provider) === "openrouter" && isAnthropicModelRef(modelId)
+  );
 }
 
 export function isAnthropicFamilyCacheTtlEligible(params: {
@@ -49,7 +56,7 @@ export function isAnthropicFamilyCacheTtlEligible(params: {
   modelApi?: string;
   modelId: string;
 }): boolean {
-  const normalizedProvider = params.provider.trim().toLowerCase();
+  const normalizedProvider = normalizeOptionalLowercaseString(params.provider);
   if (normalizedProvider === "anthropic" || normalizedProvider === "anthropic-vertex") {
     return true;
   }
@@ -65,7 +72,7 @@ export function resolveAnthropicCacheRetentionFamily(params: {
   modelId?: string;
   hasExplicitCacheConfig: boolean;
 }): AnthropicCacheRetentionFamily | undefined {
-  const normalizedProvider = params.provider.trim().toLowerCase();
+  const normalizedProvider = normalizeOptionalLowercaseString(params.provider);
   if (normalizedProvider === "anthropic" || normalizedProvider === "anthropic-vertex") {
     return "anthropic-direct";
   }
diff --git a/src/agents/pi-embedded-runner/model.inline-provider.ts b/src/agents/pi-embedded-runner/model.inline-provider.ts
index 1f30f423a6..db698c525b 100644
--- a/src/agents/pi-embedded-runner/model.inline-provider.ts
+++ b/src/agents/pi-embedded-runner/model.inline-provider.ts
@@ -1,6 +1,7 @@
 import type { Api } from "@mariozechner/pi-ai";
 import type { ModelDefinitionConfig, ModelProviderConfig } from "../../config/types.js";
 import { normalizeGoogleApiBaseUrl } from "../../infra/google-api-base-url.js";
+import { normalizeOptionalLowercaseString } from "../../shared/string-coerce.js";
 import { isSecretRefHeaderValueMarker } from "../model-auth-markers.js";
 import {
   attachModelProviderRequestTransport,
@@ -68,12 +69,12 @@ function isLegacyFoundryVisionModelCandidate(params: {
   modelId?: string;
   modelName?: string;
 }): boolean {
-  if (params.provider?.trim().toLowerCase() !== "microsoft-foundry") {
+  if (normalizeOptionalLowercaseString(params.provider) !== "microsoft-foundry") {
     return false;
   }
   const normalizedCandidates = [params.modelId, params.modelName]
     .filter((value): value is string => typeof value === "string")
-    .map((value) => value.trim().toLowerCase())
+    .map((value) => normalizeOptionalLowercaseString(value))
     .filter(Boolean);
   return normalizedCandidates.some(
     (candidate) =>
diff --git a/src/agents/pi-embedded-runner/prompt-cache-retention.ts b/src/agents/pi-embedded-runner/prompt-cache-retention.ts
index f967bcfd58..5b5c0d5357 100644
--- a/src/agents/pi-embedded-runner/prompt-cache-retention.ts
+++ b/src/agents/pi-embedded-runner/prompt-cache-retention.ts
@@ -1,3 +1,4 @@
+import { normalizeLowercaseStringOrEmpty } from "../../shared/string-coerce.js";
 import { resolveAnthropicCacheRetentionFamily } from "./anthropic-family-cache-semantics.js";
 
 type CacheRetention = "none" | "short" | "long";
@@ -9,7 +10,7 @@ export function isGooglePromptCacheEligible(params: {
   if (params.modelApi !== "google-generative-ai") {
     return false;
   }
-  const normalizedModelId = params.modelId?.trim().toLowerCase() ?? "";
+  const normalizedModelId = normalizeLowercaseStringOrEmpty(params.modelId);
   return normalizedModelId.startsWith("gemini-2.5") || normalizedModelId.startsWith("gemini-3");
 }
 
diff --git a/src/agents/provider-attribution.ts b/src/agents/provider-attribution.ts
index e17d81e7d8..892bbf6e3b 100644
--- a/src/agents/provider-attribution.ts
+++ b/src/agents/provider-attribution.ts
@@ -1,3 +1,7 @@
+import {
+  normalizeOptionalLowercaseString,
+  normalizeOptionalString,
+} from "../shared/string-coerce.js";
 import type { RuntimeVersionEnv } from "../version.js";
 import { resolveRuntimeServiceVersion } from "../version.js";
 import { normalizeProviderId } from "./provider-id.js";
@@ -129,7 +133,7 @@ function formatOpenClawUserAgent(version: string): string {
 
 function tryParseHostname(value: string): string | undefined {
   try {
-    return new URL(value).hostname.toLowerCase();
+    return normalizeOptionalLowercaseString(new URL(value).hostname);
   } catch {
     return undefined;
   }
@@ -140,11 +144,10 @@ function isSchemelessHostnameCandidate(value: string): boolean {
 }
 
 function resolveUrlHostname(value: unknown): string | undefined {
-  if (typeof value !== "string" || !value.trim()) {
+  const trimmed = normalizeOptionalString(value);
+  if (!trimmed) {
     return undefined;
   }
-
-  const trimmed = value.trim();
   const parsedHostname = tryParseHostname(trimmed);
   if (parsedHostname) {
     return parsedHostname;
@@ -156,7 +159,7 @@ function resolveUrlHostname(value: unknown): string | undefined {
 }
 
 function normalizeComparableBaseUrl(value: string): string | undefined {
-  const trimmed = value.trim();
+  const trimmed = normalizeOptionalString(value);
   if (!trimmed) {
     return undefined;
   }
@@ -172,7 +175,7 @@ function normalizeComparableBaseUrl(value: string): string | undefined {
     }
     url.hash = "";
     url.search = "";
-    return url.toString().replace(/\/+$/, "").toLowerCase();
+    return normalizeOptionalLowercaseString(url.toString().replace(/\/+$/, ""));
   } catch {
     return undefined;
   }
@@ -465,7 +468,7 @@ export function resolveProviderRequestPolicy(
   const policy = resolveProviderAttributionPolicy(provider, env);
   const endpointResolution = resolveProviderEndpoint(input.baseUrl);
   const endpointClass = endpointResolution.endpointClass;
-  const api = input.api?.trim().toLowerCase();
+  const api = normalizeOptionalLowercaseString(input.api);
   const usesConfiguredBaseUrl = endpointClass !== "default";
   const usesKnownNativeOpenAIEndpoint =
     endpointClass === "openai-public" ||
@@ -535,8 +538,8 @@ export function resolveProviderRequestCapabilities(
 ): ProviderRequestCapabilities {
   const policy = resolveProviderRequestPolicy(input, env);
   const provider = policy.provider;
-  const api = input.api?.trim().toLowerCase();
-  const normalizedModelId = input.modelId?.trim().toLowerCase();
+  const api = normalizeOptionalLowercaseString(input.api);
+  const normalizedModelId = normalizeOptionalLowercaseString(input.modelId);
   const endpointClass = policy.endpointClass;
   const isKnownNativeEndpoint =
     endpointClass === "anthropic-public" ||
diff --git a/src/agents/system-prompt.ts b/src/agents/system-prompt.ts
index 13f3cd67aa..cf41a70bce 100644
--- a/src/agents/system-prompt.ts
+++ b/src/agents/system-prompt.ts
@@ -5,6 +5,10 @@ import { resolveChannelApprovalCapability } from "../channels/plugins/approvals.
 import { getChannelPlugin } from "../channels/plugins/index.js";
 import type { MemoryCitationsMode } from "../config/types.memory.js";
 import { buildMemoryPromptSection } from "../plugins/memory-state.js";
+import {
+  normalizeLowercaseStringOrEmpty,
+  normalizeOptionalLowercaseString,
+} from "../shared/string-coerce.js";
 import { listDeliverableMessageChannels } from "../utils/message-channel.js";
 import type { ResolvedTimeFormat } from "./date-time.js";
 import type { EmbeddedContextFile } from "./pi-embedded-helpers.js";
@@ -47,7 +51,7 @@ function normalizeContextFilePath(pathValue: string): string {
 
 function getContextFileBasename(pathValue: string): string {
   const normalizedPath = normalizeContextFilePath(pathValue);
-  return (normalizedPath.split("/").pop() ?? normalizedPath).toLowerCase();
+  return normalizeLowercaseStringOrEmpty(normalizedPath.split("/").pop() ?? normalizedPath);
 }
 
 function isDynamicContextFile(pathValue: string): boolean {
@@ -297,7 +301,7 @@ function buildExecApprovalPromptGuidance(params: {
   runtimeChannel?: string;
   inlineButtonsEnabled?: boolean;
 }) {
-  const runtimeChannel = params.runtimeChannel?.trim().toLowerCase();
+  const runtimeChannel = normalizeOptionalLowercaseString(params.runtimeChannel);
   const usesNativeApprovalUi =
     runtimeChannel === "webchat" ||
     params.inlineButtonsEnabled === true ||
@@ -368,7 +372,7 @@ export function buildAgentSystemPrompt(params: {
   // Preserve caller casing while deduping tool names by lowercase.
   const canonicalByNormalized = new Map<string, string>();
   for (const name of canonicalToolNames) {
-    const normalized = name.toLowerCase();
+    const normalized = normalizeLowercaseStringOrEmpty(name);
     if (!canonicalByNormalized.has(normalized)) {
       canonicalByNormalized.set(normalized, name);
     }
@@ -376,7 +380,7 @@ export function buildAgentSystemPrompt(params: {
   const resolveToolName = (normalized: string) =>
     canonicalByNormalized.get(normalized) ?? normalized;
 
-  const normalizedTools = canonicalToolNames.map((tool) => tool.toLowerCase());
+  const normalizedTools = canonicalToolNames.map((tool) => normalizeLowercaseStringOrEmpty(tool));
   const availableTools = new Set(normalizedTools);
   const hasSessionsSpawn = availableTools.has("sessions_spawn");
   const hasUpdatePlanTool = availableTools.has("update_plan");
@@ -430,10 +434,10 @@ export function buildAgentSystemPrompt(params: {
       ? normalizeStructuredPromptSection(params.heartbeatPrompt)
       : undefined;
   const runtimeInfo = params.runtimeInfo;
-  const runtimeChannel = runtimeInfo?.channel?.trim().toLowerCase();
+  const runtimeChannel = normalizeOptionalLowercaseString(runtimeInfo?.channel);
   const runtimeCapabilities = runtimeInfo?.capabilities ?? [];
   const runtimeCapabilitiesLower = new Set(
-    runtimeCapabilities.map((cap) => String(cap).trim().toLowerCase()).filter(Boolean),
+    runtimeCapabilities.map((cap) => normalizeLowercaseStringOrEmpty(String(cap))).filter(Boolean),
   );
   const inlineButtonsEnabled = runtimeCapabilitiesLower.has("inlinebuttons");
   const messageChannelOptions = listDeliverableMessageChannels().join("|");
diff --git a/src/agents/tool-policy-shared.ts b/src/agents/tool-policy-shared.ts
index e28c623de4..cb811a32c3 100644
--- a/src/agents/tool-policy-shared.ts
+++ b/src/agents/tool-policy-shared.ts
@@ -1,3 +1,4 @@
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import {
   CORE_TOOL_GROUPS,
   resolveCoreToolProfilePolicy,
@@ -17,7 +18,7 @@ const TOOL_NAME_ALIASES: Record<string, string> = {
 export const TOOL_GROUPS: Record<string, string[]> = { ...CORE_TOOL_GROUPS };
 
 export function normalizeToolName(name: string) {
-  const normalized = name.trim().toLowerCase();
+  const normalized = normalizeLowercaseStringOrEmpty(name);
   return TOOL_NAME_ALIASES[normalized] ?? normalized;
 }