diff --git a/extensions/line/src/bot-message-context.ts b/extensions/line/src/bot-message-context.ts
index 8a65d3daf34..cb2989b2506 100644
--- a/extensions/line/src/bot-message-context.ts
+++ b/extensions/line/src/bot-message-context.ts
@@ -24,7 +24,7 @@ import {
 import { logVerbose, shouldLogVerbose } from "openclaw/plugin-sdk/runtime-env";
 import { normalizeOptionalString } from "openclaw/plugin-sdk/text-runtime";
 import { normalizeAllowFrom } from "./bot-access.js";
-import { resolveLineGroupConfigEntry, resolveLineGroupHistoryKey } from "./group-keys.js";
+import { resolveLineGroupConfigEntry } from "./group-keys.js";
 import type { LineGroupConfig, ResolvedLineAccount } from "./types.js";
 
 type EventSource = webhook.Source | undefined;
@@ -77,10 +77,9 @@ function buildPeerId(source: EventSource): string {
   if (!source) {
     return "unknown";
   }
-  const groupKey = resolveLineGroupHistoryKey({
-    groupId: source.type === "group" ? source.groupId : undefined,
-    roomId: source.type === "room" ? source.roomId : undefined,
-  });
+  const groupKey =
+    normalizeOptionalString(source.type === "group" ? source.groupId : undefined) ??
+    normalizeOptionalString(source.type === "room" ? source.roomId : undefined);
   if (groupKey) {
     return groupKey;
   }
diff --git a/extensions/line/src/group-keys.test.ts b/extensions/line/src/group-keys.test.ts
index 673d0af1136..c079bc77455 100644
--- a/extensions/line/src/group-keys.test.ts
+++ b/extensions/line/src/group-keys.test.ts
@@ -2,7 +2,6 @@ import { describe, expect, it } from "vitest";
 import {
   resolveExactLineGroupConfigKey,
   resolveLineGroupConfigEntry,
-  resolveLineGroupHistoryKey,
   resolveLineGroupLookupIds,
   resolveLineGroupsConfig,
 } from "./group-keys.js";
@@ -39,14 +38,6 @@ describe("resolveLineGroupConfigEntry", () => {
   });
 });
 
-describe("resolveLineGroupHistoryKey", () => {
-  it("uses the raw group or room id as the shared LINE peer key", () => {
-    expect(resolveLineGroupHistoryKey({ groupId: "g1" })).toBe("g1");
-    expect(resolveLineGroupHistoryKey({ roomId: "r1" })).toBe("r1");
-    expect(resolveLineGroupHistoryKey({})).toBeUndefined();
-  });
-});
-
 describe("account-scoped LINE groups", () => {
   it("resolves the effective account-scoped groups map", () => {
     const cfg = {
diff --git a/extensions/line/src/group-keys.ts b/extensions/line/src/group-keys.ts
index 41a4f6ae57c..46aeb7fec92 100644
--- a/extensions/line/src/group-keys.ts
+++ b/extensions/line/src/group-keys.ts
@@ -1,7 +1,6 @@
 import { normalizeAccountId } from "openclaw/plugin-sdk/account-id";
 import type { OpenClawConfig } from "openclaw/plugin-sdk/account-resolution";
 import { resolveAccountEntry } from "openclaw/plugin-sdk/account-resolution";
-import { normalizeOptionalString } from "openclaw/plugin-sdk/text-runtime";
 import type { LineConfig, LineGroupConfig } from "./types.js";
 
 export function resolveLineGroupLookupIds(groupId?: string | null): string[] {
@@ -64,10 +63,3 @@ export function resolveExactLineGroupConfigKey(params: {
     Object.hasOwn(groups, candidate),
   );
 }
-
-export function resolveLineGroupHistoryKey(params: {
-  groupId?: string | null;
-  roomId?: string | null;
-}): string | undefined {
-  return normalizeOptionalString(params.groupId) ?? normalizeOptionalString(params.roomId);
-}
diff --git a/src/agents/identity.ts b/src/agents/identity.ts
index d6cd654ea76..8500a35775d 100644
--- a/src/agents/identity.ts
+++ b/src/agents/identity.ts
@@ -1,5 +1,4 @@
 import type { OpenClawConfig, HumanDelayConfig, IdentityConfig } from "../config/config.js";
-import { normalizeOptionalString } from "../shared/string-coerce.js";
 import { resolveAgentConfig } from "./agent-scope.js";
 
 const DEFAULT_ACK_REACTION = "👀";
@@ -57,11 +56,6 @@ export function resolveIdentityNamePrefix(
   return `[${name}]`;
 }
 
-/** Returns just the identity name (without brackets) for template context. */
-export function resolveIdentityName(cfg: OpenClawConfig, agentId: string): string | undefined {
-  return normalizeOptionalString(resolveAgentIdentity(cfg, agentId)?.name);
-}
-
 export function resolveMessagePrefix(
   cfg: OpenClawConfig,
   agentId: string,
diff --git a/src/auto-reply/reply/commands-acp/diagnostics.ts b/src/auto-reply/reply/commands-acp/diagnostics.ts
index b13cdca4199..e5168aa453f 100644
--- a/src/auto-reply/reply/commands-acp/diagnostics.ts
+++ b/src/auto-reply/reply/commands-acp/diagnostics.ts
@@ -15,7 +15,6 @@ import {
   ACP_SESSIONS_USAGE,
   formatAcpCapabilitiesText,
   resolveAcpInstallCommandHint,
-  resolveConfiguredAcpBackendId,
   stopWithText,
 } from "./shared.js";
 import { resolveBoundAcpThreadSessionKey } from "./targets.js";
@@ -28,7 +27,7 @@ export async function handleAcpDoctorAction(
     return stopWithText(`⚠️ ${ACP_DOCTOR_USAGE}`);
   }
 
-  const backendId = resolveConfiguredAcpBackendId(params.cfg);
+  const backendId = normalizeOptionalString(params.cfg.acp?.backend) ?? "acpx";
   const installHint = resolveAcpInstallCommandHint(params.cfg);
   const registeredBackend = getAcpRuntimeBackend(backendId);
   const managerSnapshot = getAcpSessionManager().getObservabilitySnapshot(params.cfg);
@@ -116,7 +115,7 @@ export function handleAcpInstallAction(
   if (restTokens.length > 0) {
     return stopWithText(`⚠️ ${ACP_INSTALL_USAGE}`);
   }
-  const backendId = resolveConfiguredAcpBackendId(params.cfg);
+  const backendId = normalizeOptionalString(params.cfg.acp?.backend) ?? "acpx";
   const installHint = resolveAcpInstallCommandHint(params.cfg);
   const lines = [
     "ACP install:",
diff --git a/src/auto-reply/reply/commands-acp/install-hints.test.ts b/src/auto-reply/reply/commands-acp/install-hints.test.ts
index 33708e7d0a2..ed64f6faeac 100644
--- a/src/auto-reply/reply/commands-acp/install-hints.test.ts
+++ b/src/auto-reply/reply/commands-acp/install-hints.test.ts
@@ -1,7 +1,7 @@
 import path from "node:path";
 import { afterEach, describe, expect, it, vi } from "vitest";
 import type { OpenClawConfig } from "../../../config/config.js";
-import { resolveAcpInstallCommandHint, resolveConfiguredAcpBackendId } from "./install-hints.js";
+import { resolveAcpInstallCommandHint } from "./install-hints.js";
 
 function withAcpConfig(acp: OpenClawConfig["acp"]): OpenClawConfig {
   return { acp } as OpenClawConfig;
@@ -35,7 +35,6 @@ describe("ACP install hints", () => {
 
   it("returns generic plugin hint for non-acpx backend", () => {
     const cfg = withAcpConfig({ backend: "custom-backend" });
-    expect(resolveConfiguredAcpBackendId(cfg)).toBe("custom-backend");
     expect(resolveAcpInstallCommandHint(cfg)).toContain('ACP backend "custom-backend"');
   });
 });
diff --git a/src/auto-reply/reply/commands-acp/install-hints.ts b/src/auto-reply/reply/commands-acp/install-hints.ts
index 9dff3c81454..ceee50f6f14 100644
--- a/src/auto-reply/reply/commands-acp/install-hints.ts
+++ b/src/auto-reply/reply/commands-acp/install-hints.ts
@@ -5,17 +5,13 @@ import { resolveBundledPluginWorkspaceSourcePath } from "../../../plugins/bundle
 import { resolveBundledPluginInstallCommandHint } from "../../../plugins/bundled-sources.js";
 import { normalizeOptionalString } from "../../../shared/string-coerce.js";
 
-export function resolveConfiguredAcpBackendId(cfg: OpenClawConfig): string {
-  return normalizeOptionalString(cfg.acp?.backend) || "acpx";
-}
-
 export function resolveAcpInstallCommandHint(cfg: OpenClawConfig): string {
   const configured = normalizeOptionalString(cfg.acp?.runtime?.installCommand);
   if (configured) {
     return configured;
   }
   const workspaceDir = process.cwd();
-  const backendId = resolveConfiguredAcpBackendId(cfg).toLowerCase();
+  const backendId = normalizeOptionalString(cfg.acp?.backend)?.toLowerCase() ?? "acpx";
   if (backendId === "acpx") {
     const workspaceLocalPath = resolveBundledPluginWorkspaceSourcePath({
       rootDir: workspaceDir,
diff --git a/src/auto-reply/reply/commands-acp/shared.ts b/src/auto-reply/reply/commands-acp/shared.ts
index e064c35f9be..c589a347126 100644
--- a/src/auto-reply/reply/commands-acp/shared.ts
+++ b/src/auto-reply/reply/commands-acp/shared.ts
@@ -8,7 +8,7 @@ import { normalizeAgentId } from "../../../routing/session-key.js";
 import { normalizeOptionalString } from "../../../shared/string-coerce.js";
 import type { CommandHandlerResult, HandleCommandsParams } from "../commands-types.js";
 import { resolveAcpCommandChannel, resolveAcpCommandThreadId } from "./context.js";
-export { resolveAcpInstallCommandHint, resolveConfiguredAcpBackendId } from "./install-hints.js";
+export { resolveAcpInstallCommandHint } from "./install-hints.js";
 
 export const COMMAND = "/acp";
 export const ACP_SPAWN_USAGE =
diff --git a/src/channels/reply-prefix.ts b/src/channels/reply-prefix.ts
index e3292ca80ea..857dd71ca52 100644
--- a/src/channels/reply-prefix.ts
+++ b/src/channels/reply-prefix.ts
@@ -1,10 +1,11 @@
-import { resolveEffectiveMessagesConfig, resolveIdentityName } from "../agents/identity.js";
+import { resolveAgentIdentity, resolveEffectiveMessagesConfig } from "../agents/identity.js";
 import {
   extractShortModelName,
   type ResponsePrefixContext,
 } from "../auto-reply/reply/response-prefix-template.js";
 import type { GetReplyOptions } from "../auto-reply/types.js";
 import type { OpenClawConfig } from "../config/config.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 
 type ModelSelectionContext = Parameters<NonNullable<GetReplyOptions["onModelSelected"]>>[0];
 
@@ -28,7 +29,7 @@ export function createReplyPrefixContext(params: {
 }): ReplyPrefixContextBundle {
   const { cfg, agentId } = params;
   const prefixContext: ResponsePrefixContext = {
-    identityName: resolveIdentityName(cfg, agentId),
+    identityName: normalizeOptionalString(resolveAgentIdentity(cfg, agentId)?.name),
   };
 
   const onModelSelected = (ctx: ModelSelectionContext) => {
diff --git a/src/plugins/provider-registry-shared.test.ts b/src/plugins/provider-registry-shared.test.ts
index 95c84c472ad..b756bfb0be8 100644
--- a/src/plugins/provider-registry-shared.test.ts
+++ b/src/plugins/provider-registry-shared.test.ts
@@ -1,13 +1,10 @@
 import { describe, expect, it } from "vitest";
-import {
-  buildCapabilityProviderMaps,
-  normalizeCapabilityProviderId,
-} from "./provider-registry-shared.js";
+import { buildCapabilityProviderMaps } from "./provider-registry-shared.js";
 
 describe("provider registry shared", () => {
   it("normalizes provider ids case-insensitively", () => {
-    expect(normalizeCapabilityProviderId("  OpenAI  ")).toBe("openai");
-    expect(normalizeCapabilityProviderId("   ")).toBeUndefined();
+    const { canonical } = buildCapabilityProviderMaps([{ id: "  OpenAI  " }, { id: "   " }]);
+    expect([...canonical.keys()]).toEqual(["openai"]);
   });
 
   it("indexes providers by id and alias", () => {
diff --git a/src/plugins/provider-registry-shared.ts b/src/plugins/provider-registry-shared.ts
index 48a38f3fe45..f23fe7b96fc 100644
--- a/src/plugins/provider-registry-shared.ts
+++ b/src/plugins/provider-registry-shared.ts
@@ -1,14 +1,9 @@
 import { normalizeOptionalString } from "../shared/string-coerce.js";
 
-export function normalizeCapabilityProviderId(providerId: string | undefined): string | undefined {
-  return normalizeOptionalString(providerId)?.toLowerCase();
-}
-
 export function buildCapabilityProviderMaps<T extends { id: string; aliases?: readonly string[] }>(
   providers: readonly T[],
-  normalizeId: (
-    providerId: string | undefined,
-  ) => string | undefined = normalizeCapabilityProviderId,
+  normalizeId: (providerId: string | undefined) => string | undefined = (providerId) =>
+    normalizeOptionalString(providerId)?.toLowerCase(),
 ): {
   canonical: Map<string, T>;
   aliases: Map<string, T>;
diff --git a/src/realtime-voice/provider-registry.ts b/src/realtime-voice/provider-registry.ts
index c7146580b79..ef5304e0665 100644
--- a/src/realtime-voice/provider-registry.ts
+++ b/src/realtime-voice/provider-registry.ts
@@ -1,16 +1,14 @@
 import type { OpenClawConfig } from "../config/config.js";
 import { resolvePluginCapabilityProviders } from "../plugins/capability-provider-runtime.js";
-import {
-  buildCapabilityProviderMaps,
-  normalizeCapabilityProviderId,
-} from "../plugins/provider-registry-shared.js";
+import { buildCapabilityProviderMaps } from "../plugins/provider-registry-shared.js";
 import type { RealtimeVoiceProviderPlugin } from "../plugins/types.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import type { RealtimeVoiceProviderId } from "./provider-types.js";
 
 export function normalizeRealtimeVoiceProviderId(
   providerId: string | undefined,
 ): RealtimeVoiceProviderId | undefined {
-  return normalizeCapabilityProviderId(providerId);
+  return normalizeOptionalString(providerId)?.toLowerCase();
 }
 
 function resolveRealtimeVoiceProviderEntries(cfg?: OpenClawConfig): RealtimeVoiceProviderPlugin[] {
diff --git a/src/tasks/task-registry.ts b/src/tasks/task-registry.ts
index 5014bb32447..93315424a40 100644
--- a/src/tasks/task-registry.ts
+++ b/src/tasks/task-registry.ts
@@ -523,8 +523,8 @@ function taskRunScopeKey(
   return [
     task.runtime,
     task.scopeKind,
-    normalizeComparableText(task.ownerKey),
-    normalizeComparableText(task.childSessionKey),
+    normalizeOptionalString(task.ownerKey) ?? "",
+    normalizeOptionalString(task.childSessionKey) ?? "",
   ].join("\u0000");
 }
 
@@ -562,9 +562,10 @@ function getPeerTasksForDelivery(task: TaskRecord): TaskRecord[] {
     (candidate) =>
       candidate.runtime === task.runtime &&
       candidate.scopeKind === task.scopeKind &&
-      normalizeComparableText(candidate.ownerKey) === normalizeComparableText(task.ownerKey) &&
-      normalizeComparableText(candidate.childSessionKey) ===
-        normalizeComparableText(task.childSessionKey),
+      (normalizeOptionalString(candidate.ownerKey) ?? "") ===
+        (normalizeOptionalString(task.ownerKey) ?? "") &&
+      (normalizeOptionalString(candidate.childSessionKey) ?? "") ===
+        (normalizeOptionalString(task.childSessionKey) ?? ""),
   );
 }
 
@@ -583,10 +584,6 @@ function pickPreferredRunIdTask(matches: TaskRecord[]): TaskRecord | undefined {
   })[0];
 }
 
-function normalizeComparableText(value: string | undefined): string {
-  return normalizeOptionalString(value) ?? "";
-}
-
 function compareTasksNewestFirst(
   left: Pick<TaskRecord, "createdAt"> & { insertionIndex?: number },
   right: Pick<TaskRecord, "createdAt"> & { insertionIndex?: number },
@@ -614,18 +611,21 @@ function findExistingTaskForCreate(params: {
         (task) =>
           task.runtime === params.runtime &&
           task.scopeKind === params.scopeKind &&
-          normalizeComparableText(task.ownerKey) === normalizeComparableText(params.ownerKey) &&
-          normalizeComparableText(task.childSessionKey) ===
-            normalizeComparableText(params.childSessionKey) &&
-          normalizeComparableText(task.parentFlowId) ===
-            normalizeComparableText(params.parentFlowId),
+          (normalizeOptionalString(task.ownerKey) ?? "") ===
+            (normalizeOptionalString(params.ownerKey) ?? "") &&
+          (normalizeOptionalString(task.childSessionKey) ?? "") ===
+            (normalizeOptionalString(params.childSessionKey) ?? "") &&
+          (normalizeOptionalString(task.parentFlowId) ?? "") ===
+            (normalizeOptionalString(params.parentFlowId) ?? ""),
       )
     : [];
   const exact = runId
     ? runScopeMatches.find(
         (task) =>
-          normalizeComparableText(task.label) === normalizeComparableText(params.label) &&
-          normalizeComparableText(task.task) === normalizeComparableText(params.task),
+          (normalizeOptionalString(task.label) ?? "") ===
+            (normalizeOptionalString(params.label) ?? "") &&
+          (normalizeOptionalString(task.task) ?? "") ===
+            (normalizeOptionalString(params.task) ?? ""),
       )
     : undefined;
   if (exact) {
@@ -688,11 +688,11 @@ function mergeExistingTaskForCreate(
   }
   const nextLabel = params.label?.trim();
   if (params.preferMetadata) {
-    if (nextLabel && normalizeComparableText(existing.label) !== nextLabel) {
+    if (nextLabel && (normalizeOptionalString(existing.label) ?? "") !== nextLabel) {
       patch.label = nextLabel;
     }
     const nextTask = params.task.trim();
-    if (nextTask && normalizeComparableText(existing.task) !== nextTask) {
+    if (nextTask && (normalizeOptionalString(existing.task) ?? "") !== nextTask) {
       patch.task = nextTask;
     }
   } else if (nextLabel && !existing.label?.trim()) {
diff --git a/src/tts/provider-registry.ts b/src/tts/provider-registry.ts
index 1b9f3041499..bd7d84b5103 100644
--- a/src/tts/provider-registry.ts
+++ b/src/tts/provider-registry.ts
@@ -1,16 +1,14 @@
 import type { OpenClawConfig } from "../config/config.js";
 import { resolvePluginCapabilityProviders } from "../plugins/capability-provider-runtime.js";
-import {
-  buildCapabilityProviderMaps,
-  normalizeCapabilityProviderId,
-} from "../plugins/provider-registry-shared.js";
+import { buildCapabilityProviderMaps } from "../plugins/provider-registry-shared.js";
 import type { SpeechProviderPlugin } from "../plugins/types.js";
+import { normalizeOptionalString } from "../shared/string-coerce.js";
 import type { SpeechProviderId } from "./provider-types.js";
 
 export function normalizeSpeechProviderId(
   providerId: string | undefined,
 ): SpeechProviderId | undefined {
-  return normalizeCapabilityProviderId(providerId);
+  return normalizeOptionalString(providerId)?.toLowerCase();
 }
 
 function resolveSpeechProviderPluginEntries(cfg?: OpenClawConfig): SpeechProviderPlugin[] {