refactor: dedupe command config lowercase helpers

src/commands/agents.commands.add.ts

@@ -12,6 +12,7 @@ import { logConfigUpdated } from "../config/logging.js";
 import { DEFAULT_AGENT_ID, normalizeAgentId } from "../routing/session-key.js";
 import { type RuntimeEnv, writeRuntimeJson } from "../runtime.js";
 import { defaultRuntime } from "../runtime.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { resolveUserPath, shortenHomePath } from "../utils.js";
 import { createClackPrompter } from "../wizard/clack-prompter.js";
 import { WizardCancelledError } from "../wizard/prompts.js";
@@ -241,7 +242,8 @@ export async function agentsAddCommand(
       const sourceAuthPath = resolveAuthStorePath(resolveAgentDir(cfg, defaultAgentId));
       const destAuthPath = resolveAuthStorePath(agentDir);
       const sameAuthPath =
-        path.resolve(sourceAuthPath).toLowerCase() === path.resolve(destAuthPath).toLowerCase();
+        normalizeLowercaseStringOrEmpty(path.resolve(sourceAuthPath)) ===
+        normalizeLowercaseStringOrEmpty(path.resolve(destAuthPath));
       if (
         !sameAuthPath &&
         (await fileExists(sourceAuthPath)) &&

src/commands/channels/logs.ts

@@ -108,7 +108,7 @@ export async function channelsLogsCommand(
   }
   for (const line of lines) {
     const ts = line.time ? `${line.time} ` : "";
-    const level = line.level ? `${line.level.toLowerCase()} ` : "";
+    const level = line.level ? `${normalizeLowercaseStringOrEmpty(line.level)} ` : "";
     runtime.log(`${ts}${level}${line.message}`.trim());
   }
 }

src/commands/doctor-gateway-services.ts

@@ -21,7 +21,10 @@ import {
 import { resolveGatewayService } from "../daemon/service.js";
 import { uninstallLegacySystemdUnits } from "../daemon/systemd.js";
 import type { RuntimeEnv } from "../runtime.js";
-import { normalizeOptionalString } from "../shared/string-coerce.js";
+import {
+  normalizeLowercaseStringOrEmpty,
+  normalizeOptionalString,
+} from "../shared/string-coerce.js";
 import { note } from "../terminal/note.js";
 import { buildGatewayInstallPlan } from "./daemon-install-helpers.js";
 import { DEFAULT_GATEWAY_DAEMON_RUNTIME, type GatewayDaemonRuntime } from "./daemon-runtime.js";
@@ -34,7 +37,7 @@ const execFileAsync = promisify(execFile);
 function detectGatewayRuntime(programArguments: string[] | undefined): GatewayDaemonRuntime {
   const first = programArguments?.[0];
   if (first) {
-    const base = path.basename(first).toLowerCase();
+    const base = normalizeLowercaseStringOrEmpty(path.basename(first));
     if (base === "bun" || base === "bun.exe") {
       return "bun";
     }

src/commands/doctor-update.ts

@@ -3,6 +3,7 @@ import { isTruthyEnvValue } from "../infra/env.js";
 import { runGatewayUpdate } from "../infra/update-runner.js";
 import { runCommandWithTimeout } from "../process/exec.js";
 import type { RuntimeEnv } from "../runtime.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { note } from "../terminal/note.js";
 import type { DoctorOptions } from "./doctor-prompter.js";
 
@@ -16,7 +17,7 @@ async function detectOpenClawGitCheckout(root: string): Promise<"git" | "not-git
   if (res.code !== 0) {
     // Avoid noisy "Update via package manager" notes when git is missing/broken,
     // but do show it when this is clearly not a git checkout.
-    if (res.stderr.toLowerCase().includes("not a git repository")) {
+    if (normalizeLowercaseStringOrEmpty(res.stderr).includes("not a git repository")) {
       return "not-git";
     }
     return "unknown";

src/commands/message.ts

@@ -12,6 +12,7 @@ import { loadConfig } from "../config/config.js";
 import type { OutboundSendDeps } from "../infra/outbound/deliver.js";
 import { runMessageAction } from "../infra/outbound/message-action-runner.js";
 import { type RuntimeEnv, writeRuntimeJson } from "../runtime.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { GATEWAY_CLIENT_MODES, GATEWAY_CLIENT_NAMES } from "../utils/message-channel.js";
 import { buildMessageCliJson, formatMessageCliText } from "./message-format.js";
 
@@ -42,8 +43,9 @@ export async function messageCommand(
   });
   const rawAction = typeof opts.action === "string" ? opts.action.trim() : "";
   const actionInput = rawAction || "send";
+  const normalizedActionInput = normalizeLowercaseStringOrEmpty(actionInput);
   const actionMatch = (CHANNEL_MESSAGE_ACTION_NAMES as readonly string[]).find(
-    (name) => name.toLowerCase() === actionInput.toLowerCase(),
+    (name) => normalizeLowercaseStringOrEmpty(name) === normalizedActionInput,
   );
   if (!actionMatch) {
     throw new Error(`Unknown message action: ${actionInput}`);

src/commands/models/list.auth-overview.ts

@@ -13,6 +13,7 @@ import {
   resolveUsableCustomProviderApiKey,
 } from "../../agents/model-auth.js";
 import type { OpenClawConfig } from "../../config/config.js";
+import { normalizeLowercaseStringOrEmpty } from "../../shared/string-coerce.js";
 import { shortenHomePath } from "../../utils.js";
 import { maskApiKey } from "./list.format.js";
 import type { ProviderAuthOverview } from "./list.types.js";
@@ -113,8 +114,9 @@ export function resolveProviderAuthOverview(params: {
       };
     }
     if (envKey) {
+      const normalizedSource = normalizeLowercaseStringOrEmpty(envKey.source);
       const isOAuthEnv =
-        envKey.source.includes("OAUTH_TOKEN") || envKey.source.toLowerCase().includes("oauth");
+        envKey.source.includes("OAUTH_TOKEN") || normalizedSource.includes("oauth");
       return {
         kind: "env",
         detail: isOAuthEnv ? "OAuth (env)" : maskApiKey(envKey.apiKey),
@@ -139,10 +141,12 @@ export function resolveProviderAuthOverview(params: {
     ...(envKey
       ? {
           env: {
-            value:
-              envKey.source.includes("OAUTH_TOKEN") || envKey.source.toLowerCase().includes("oauth")
+            value: (() => {
+              const normalizedSource = normalizeLowercaseStringOrEmpty(envKey.source);
+              return envKey.source.includes("OAUTH_TOKEN") || normalizedSource.includes("oauth")
                 ? "OAuth (env)"
-                : maskApiKey(envKey.apiKey),
+                : maskApiKey(envKey.apiKey);
+            })(),
             source: envKey.source,
           },
         }

src/commands/models/shared.ts

@@ -18,6 +18,7 @@ import { toAgentModelListLike } from "../../config/model-input.js";
 import type { AgentModelEntryConfig } from "../../config/types.agent-defaults.js";
 import type { AgentModelConfig } from "../../config/types.agents-shared.js";
 import { normalizeAgentId } from "../../routing/session-key.js";
+import { normalizeLowercaseStringOrEmpty } from "../../shared/string-coerce.js";
 
 export const ensureFlagCompatibility = (opts: { json?: boolean; plain?: boolean }) => {
   if (opts.json && opts.plain) {
@@ -51,7 +52,7 @@ export const formatMs = (value?: number | null) => {
 export const isLocalBaseUrl = (baseUrl: string) => {
   try {
     const url = new URL(baseUrl);
-    const host = url.hostname.toLowerCase();
+    const host = normalizeLowercaseStringOrEmpty(url.hostname);
     return (
       host === "localhost" ||
       host === "127.0.0.1" ||

src/commands/sandbox-explain.ts

@@ -109,13 +109,18 @@ function resolveActiveChannel(params: {
     entry?.lastProvider ??
     entry?.provider ??
     ""
-  )
-    .trim()
-    .toLowerCase();
-  if (candidate === INTERNAL_MESSAGE_CHANNEL) {
+  ).trim();
+  const normalizedCandidate = normalizeOptionalLowercaseString(candidate);
+  if (!normalizedCandidate) {
+    return inferProviderFromSessionKey({
+      cfg: params.cfg,
+      sessionKey: params.sessionKey,
+    });
+  }
+  if (normalizedCandidate === INTERNAL_MESSAGE_CHANNEL) {
     return INTERNAL_MESSAGE_CHANNEL;
   }
-  const normalized = normalizeAnyChannelId(candidate);
+  const normalized = normalizeAnyChannelId(normalizedCandidate);
   if (normalized) {
     return normalized;
   }

src/commands/status-all/gateway.ts

@@ -1,4 +1,5 @@
 import fs from "node:fs/promises";
+import { normalizeLowercaseStringOrEmpty } from "../../shared/string-coerce.js";
 
 export async function readFileTailLines(filePath: string, maxLines: number): Promise<string[]> {
   const raw = await fs.readFile(filePath, "utf8").catch(() => "");
@@ -117,7 +118,7 @@ export function summarizeLogTail(rawLines: string[], opts?: { maxLines?: number
         const code = parsed?.error?.code?.trim() || null;
         const msg = parsed?.error?.message?.trim() || null;
         const msgShort = msg
-          ? msg.toLowerCase().includes("signing in again")
+          ? normalizeLowercaseStringOrEmpty(msg).includes("signing in again")
             ? "re-auth required"
             : shorten(msg, 52)
           : null;

src/commands/status.command-sections.ts

@@ -1,5 +1,6 @@
 import type { HeartbeatEventPayload } from "../infra/heartbeat-events.js";
 import type { Tone } from "../memory-host-sdk/status.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import type { TableColumn } from "../terminal/table.js";
 import type { HealthSummary } from "./health.js";
 import type { AgentLocalStatus } from "./status.agent-local.js";
@@ -253,7 +254,7 @@ export function buildStatusHealthRows(params: {
     }
     const item = line.slice(0, colon).trim();
     const detail = line.slice(colon + 1).trim();
-    const normalized = detail.toLowerCase();
+    const normalized = normalizeLowercaseStringOrEmpty(detail);
     const status = normalized.startsWith("ok")
       ? params.ok("OK")
       : normalized.startsWith("failed")

src/commands/status.format.ts

@@ -1,5 +1,6 @@
 import { formatDurationPrecise } from "../infra/format-time/format-duration.ts";
 import { formatRuntimeStatusWithDetails } from "../infra/runtime-status.ts";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import type { SessionStatus } from "./status.types.js";
 export { shortenText } from "./text-format.js";
 
@@ -109,7 +110,8 @@ export const formatDaemonRuntimeShort = (runtime?: {
   const details: string[] = [];
   const detail = runtime.detail?.replace(/\s+/g, " ").trim() || "";
   const noisyLaunchctlDetail =
-    runtime.missingUnit === true && detail.toLowerCase().includes("could not find service");
+    runtime.missingUnit === true &&
+    normalizeLowercaseStringOrEmpty(detail).includes("could not find service");
   if (detail && !noisyLaunchctlDetail) {
     details.push(detail);
   }

src/config/agent-dirs.ts

@@ -2,6 +2,7 @@ import os from "node:os";
 import path from "node:path";
 import { resolveRequiredHomeDir } from "../infra/home-dir.js";
 import { DEFAULT_AGENT_ID, normalizeAgentId } from "../routing/session-key.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { resolveUserPath } from "../utils.js";
 import { resolveStateDir } from "./paths.js";
 import type { OpenClawConfig } from "./types.js";
@@ -24,7 +25,7 @@ export class DuplicateAgentDirError extends Error {
 function canonicalizeAgentDir(agentDir: string): string {
   const resolved = path.resolve(agentDir);
   if (process.platform === "darwin" || process.platform === "win32") {
-    return resolved.toLowerCase();
+    return normalizeLowercaseStringOrEmpty(resolved);
   }
   return resolved;
 }

src/config/allowed-values.ts

@@ -1,3 +1,5 @@
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
+
 const MAX_ALLOWED_VALUES_HINT = 12;
 const MAX_ALLOWED_VALUE_CHARS = 160;
 
@@ -86,7 +88,7 @@ export function summarizeAllowedValues(
 }
 
 function messageAlreadyIncludesAllowedValues(message: string): boolean {
-  const lower = message.toLowerCase();
+  const lower = normalizeLowercaseStringOrEmpty(message);
   return lower.includes("(allowed:") || lower.includes("expected one of");
 }
 

src/config/group-policy.ts

@@ -92,7 +92,7 @@ function normalizeSenderKey(
     return "";
   }
   const withoutAt = options.stripLeadingAt && trimmed.startsWith("@") ? trimmed.slice(1) : trimmed;
-  return withoutAt.toLowerCase();
+  return normalizeLowercaseStringOrEmpty(withoutAt);
 }
 
 function normalizeTypedSenderKey(value: string, type: SenderKeyType): string {

src/config/redact-snapshot.ts

@@ -4,6 +4,7 @@ import {
   isSensitiveUrlConfigPath,
   redactSensitiveUrlLikeString,
 } from "../shared/net/redact-sensitive-url.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import {
   replaceSensitiveValuesInRaw,
   shouldFallbackToStructuredRawRedaction,
@@ -28,7 +29,7 @@ function isEnvVarPlaceholder(value: string): boolean {
 }
 
 function isWholeObjectSensitivePath(path: string): boolean {
-  const lowered = path.toLowerCase();
+  const lowered = normalizeLowercaseStringOrEmpty(path);
   return lowered.endsWith("serviceaccount") || lowered.endsWith("serviceaccountref");
 }
 

src/config/schema.hints.ts

@@ -5,6 +5,7 @@ import {
   isSensitiveUrlConfigPath,
   SENSITIVE_URL_HINT_TAG,
 } from "../shared/net/redact-sensitive-url.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { FIELD_HELP } from "./schema.help.js";
 import { FIELD_LABELS } from "./schema.labels.js";
 import { applyDerivedTags } from "./schema.tags.js";
@@ -128,7 +129,7 @@ const SENSITIVE_KEY_WHITELIST_SUFFIXES = [
   "passwordFile",
 ] as const;
 const NORMALIZED_SENSITIVE_KEY_WHITELIST_SUFFIXES = SENSITIVE_KEY_WHITELIST_SUFFIXES.map((suffix) =>
-  suffix.toLowerCase(),
+  normalizeLowercaseStringOrEmpty(suffix),
 );
 
 const SENSITIVE_PATTERNS = [
@@ -142,7 +143,7 @@ const SENSITIVE_PATTERNS = [
 ];
 
 function isWhitelistedSensitivePath(path: string): boolean {
-  const lowerPath = path.toLowerCase();
+  const lowerPath = normalizeLowercaseStringOrEmpty(path);
   return NORMALIZED_SENSITIVE_KEY_WHITELIST_SUFFIXES.some((suffix) => lowerPath.endsWith(suffix));
 }
 

src/config/schema.tags.ts

@@ -142,7 +142,7 @@ function addTags(set: Set<ConfigTag>, tags: ReadonlyArray<ConfigTag>): void {
 }
 
 export function deriveTagsForPath(path: string, hint?: ConfigUiHint): ConfigTag[] {
-  const lowerPath = path.toLowerCase();
+  const lowerPath = normalizeLowercaseStringOrEmpty(path);
   const override = resolveOverride(path);
   if (override) {
     return normalizeTags(override);

src/config/sessions/paths.ts

@@ -3,6 +3,7 @@ import os from "node:os";
 import path from "node:path";
 import { expandHomePrefix, resolveRequiredHomeDir } from "../../infra/home-dir.js";
 import { DEFAULT_AGENT_ID, normalizeAgentId } from "../../routing/session-key.js";
+import { normalizeLowercaseStringOrEmpty } from "../../shared/string-coerce.js";
 import { resolveStateDir } from "../paths.js";
 
 function resolveAgentSessionsDir(
@@ -142,7 +143,7 @@ function resolveStructuralSessionFallbackPath(
     return undefined;
   }
   const normalizedAgentId = normalizeAgentId(agentIdPart);
-  if (normalizedAgentId !== agentIdPart.toLowerCase()) {
+  if (normalizedAgentId !== normalizeLowercaseStringOrEmpty(agentIdPart)) {
     return undefined;
   }
   if (normalizedAgentId !== normalizeAgentId(expectedAgentId)) {

src/config/sessions/reset.ts

@@ -133,7 +133,7 @@ export function resolveChannelResetConfig(params: {
   if (!key) {
     return undefined;
   }
-  return resetByChannel[key] ?? resetByChannel[key.toLowerCase()];
+  return resetByChannel[key];
 }
 
 export function evaluateSessionFreshness(params: {

src/config/types.tools.ts

@@ -1,5 +1,6 @@
 import type { ChatType } from "../channels/chat-type.js";
 import type { SafeBinProfileFixture } from "../infra/exec-safe-bin-policy.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import type { AgentElevatedAllowFromConfig, SessionSendPolicyAction } from "./types.base.js";
 import type { MemoryQmdIndexPath } from "./types.memory.js";
 import type { ConfiguredProviderRequest } from "./types.provider-request.js";
@@ -208,7 +209,7 @@ export function parseToolsBySenderTypedKey(
   if (!trimmed) {
     return undefined;
   }
-  const lowered = trimmed.toLowerCase();
+  const lowered = normalizeLowercaseStringOrEmpty(trimmed);
   for (const type of TOOLS_BY_SENDER_KEY_TYPES) {
     const prefix = `${type}:`;
     if (!lowered.startsWith(prefix)) {

src/config/validation.ts

@@ -26,6 +26,7 @@ import {
   isWindowsAbsolutePath,
 } from "../shared/avatar-policy.js";
 import { isCanonicalDottedDecimalIPv4, isLoopbackIpAddress } from "../shared/net/ip.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { isRecord } from "../utils.js";
 import { findDuplicateAgentDirs, formatDuplicateAgentDirError } from "./agent-dirs.js";
 import { appendAllowedValuesHint, summarizeAllowedValues } from "./allowed-values.js";
@@ -830,7 +831,7 @@ function validateConfigObjectWithPluginsBase(
 
   const heartbeatChannelIds = new Set<string>();
   for (const channelId of CHANNEL_IDS) {
-    heartbeatChannelIds.add(channelId.toLowerCase());
+    heartbeatChannelIds.add(normalizeLowercaseStringOrEmpty(channelId));
   }
 
   const validateHeartbeatTarget = (target: string | undefined, path: string) => {
@@ -842,7 +843,7 @@ function validateConfigObjectWithPluginsBase(
       issues.push({ path, message: "heartbeat target must not be empty" });
       return;
     }
-    const normalized = trimmed.toLowerCase();
+    const normalized = normalizeLowercaseStringOrEmpty(trimmed);
     if (normalized === "last" || normalized === "none") {
       return;
     }
@@ -855,7 +856,7 @@ function validateConfigObjectWithPluginsBase(
         for (const channelId of record.channels) {
           const pluginChannel = channelId.trim();
           if (pluginChannel) {
-            heartbeatChannelIds.add(pluginChannel.toLowerCase());
+            heartbeatChannelIds.add(normalizeLowercaseStringOrEmpty(pluginChannel));
           }
         }
       }

src/shared/avatar-policy.ts

@@ -1,4 +1,5 @@
 import path from "node:path";
+import { normalizeLowercaseStringOrEmpty } from "./string-coerce.js";
 
 export const AVATAR_MAX_BYTES = 2 * 1024 * 1024;
 
@@ -25,7 +26,7 @@ export const WINDOWS_ABS_RE = /^[a-zA-Z]:[\\/]/;
 const AVATAR_PATH_EXT_RE = /\.(png|jpe?g|gif|webp|svg|ico)$/i;
 
 export function resolveAvatarMime(filePath: string): string {
-  const ext = path.extname(filePath).toLowerCase();
+  const ext = normalizeLowercaseStringOrEmpty(path.extname(filePath));
   return AVATAR_MIME_BY_EXT[ext] ?? "application/octet-stream";
 }
 
@@ -78,6 +79,6 @@ export function looksLikeAvatarPath(value: string): boolean {
 }
 
 export function isSupportedLocalAvatarExtension(filePath: string): boolean {
-  const ext = path.extname(filePath).toLowerCase();
+  const ext = normalizeLowercaseStringOrEmpty(path.extname(filePath));
   return LOCAL_AVATAR_EXTENSIONS.has(ext);
 }

src/shared/model-param-b.ts

@@ -1,5 +1,7 @@
+import { normalizeLowercaseStringOrEmpty } from "./string-coerce.js";
+
 export function inferParamBFromIdOrName(text: string): number | null {
-  const raw = text.toLowerCase();
+  const raw = normalizeLowercaseStringOrEmpty(text);
   const matches = raw.matchAll(/(?:^|[^a-z0-9])[a-z]?(\d+(?:\.\d+)?)b(?:[^a-z0-9]|$)/g);
   let best: number | null = null;
   for (const match of matches) {

src/shared/net/ip.ts

@@ -1,5 +1,5 @@
 import ipaddr from "ipaddr.js";
-import { normalizeOptionalString } from "../string-coerce.js";
+import { normalizeLowercaseStringOrEmpty, normalizeOptionalString } from "../string-coerce.js";
 
 export type ParsedIpAddress = ipaddr.IPv4 | ipaddr.IPv6;
 type Ipv4Range = ReturnType<ipaddr.IPv4["range"]>;
@@ -176,7 +176,7 @@ export function normalizeIpAddress(raw: string | undefined): string | undefined
     return undefined;
   }
   const normalized = normalizeIpv4MappedAddress(parsed);
-  return normalized.toString().toLowerCase();
+  return normalizeLowercaseStringOrEmpty(normalized.toString());
 }
 
 export function isCanonicalDottedDecimalIPv4(raw: string | undefined): boolean {

src/shared/net/redact-sensitive-url.ts

@@ -1,4 +1,5 @@
 import type { ConfigUiHint } from "../config-ui-hints-types.js";
+import { normalizeLowercaseStringOrEmpty } from "../string-coerce.js";
 
 export const SENSITIVE_URL_HINT_TAG = "url-secret";
 
@@ -17,7 +18,7 @@ const SENSITIVE_URL_QUERY_PARAM_NAMES = new Set([
 ]);
 
 export function isSensitiveUrlQueryParamName(name: string): boolean {
-  return SENSITIVE_URL_QUERY_PARAM_NAMES.has(name.toLowerCase());
+  return SENSITIVE_URL_QUERY_PARAM_NAMES.has(normalizeLowercaseStringOrEmpty(name));
 }
 
 export function isSensitiveUrlConfigPath(path: string): boolean {

src/shared/node-match.ts

@@ -1,4 +1,8 @@
-import { normalizeOptionalLowercaseString, normalizeOptionalString } from "./string-coerce.js";
+import {
+  normalizeLowercaseStringOrEmpty,
+  normalizeOptionalLowercaseString,
+  normalizeOptionalString,
+} from "./string-coerce.js";
 
 export type NodeMatchCandidate = {
   nodeId: string;
@@ -15,8 +19,7 @@ type ScoredNodeMatch = {
 };
 
 export function normalizeNodeKey(value: string) {
-  return value
-    .toLowerCase()
+  return normalizeLowercaseStringOrEmpty(value)
     .replace(/[^a-z0-9]+/g, "-")
     .replace(/^-+/, "")
     .replace(/-+$/, "");

src/shared/string-normalization.ts

@@ -5,7 +5,7 @@ export function normalizeStringEntries(list?: ReadonlyArray<unknown>) {
 }
 
 export function normalizeStringEntriesLower(list?: ReadonlyArray<unknown>) {
-  return normalizeStringEntries(list).map((entry) => entry.toLowerCase());
+  return normalizeStringEntries(list).map((entry) => normalizeOptionalLowercaseString(entry) ?? "");
 }
 
 export function normalizeTrimmedStringList(value: unknown): string[] {

src/shared/text/assistant-visible-text.ts

@@ -1,3 +1,4 @@
+import { normalizeLowercaseStringOrEmpty } from "../string-coerce.js";
 import { findCodeRegions, isInsideCode } from "./code-regions.js";
 import { stripModelSpecialTokens } from "./model-special-tokens.js";
 import {
@@ -133,7 +134,7 @@ function parseToolCallTagAt(text: string, start: number): ParsedToolCallTag | nu
     cursor += 1;
   }
 
-  const tagName = text.slice(nameStart, cursor).toLowerCase();
+  const tagName = normalizeLowercaseStringOrEmpty(text.slice(nameStart, cursor));
   if (!TOOL_CALL_TAG_NAMES.has(tagName) || !isToolCallBoundary(text[cursor])) {
     return null;
   }
@@ -391,7 +392,7 @@ export function stripDowngradedToolCallText(text: string): string {
       while (index < input.length && (input[index] === " " || input[index] === "\t")) {
         index += 1;
       }
-      if (input.slice(index, index + 9).toLowerCase() === "arguments") {
+      if (normalizeLowercaseStringOrEmpty(input.slice(index, index + 9)) === "arguments") {
         index += 9;
         if (input[index] === ":") {
           index += 1;

src/shared/text/auto-linked-file-ref.ts

@@ -1,3 +1,5 @@
+import { normalizeLowercaseStringOrEmpty } from "../string-coerce.js";
+
 const FILE_REF_EXTENSIONS = ["md", "go", "py", "pl", "sh", "am", "at", "be", "cc"] as const;
 
 export const FILE_REF_EXTENSIONS_WITH_TLD = new Set<string>(FILE_REF_EXTENSIONS);
@@ -11,7 +13,7 @@ export function isAutoLinkedFileRef(href: string, label: string): boolean {
   if (dotIndex < 1) {
     return false;
   }
-  const ext = label.slice(dotIndex + 1).toLowerCase();
+  const ext = normalizeLowercaseStringOrEmpty(label.slice(dotIndex + 1));
   if (!FILE_REF_EXTENSIONS_WITH_TLD.has(ext)) {
     return false;
   }