diff --git a/src/plugins/provider-registry-shared.ts b/src/plugins/provider-registry-shared.ts
index f23fe7b96fc..48a38f3fe45 100644
--- a/src/plugins/provider-registry-shared.ts
+++ b/src/plugins/provider-registry-shared.ts
@@ -1,9 +1,14 @@
 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 = (providerId) =>
-    normalizeOptionalString(providerId)?.toLowerCase(),
+  normalizeId: (
+    providerId: string | undefined,
+  ) => string | undefined = normalizeCapabilityProviderId,
 ): {
   canonical: Map<string, T>;
   aliases: Map<string, T>;
diff --git a/src/realtime-transcription/provider-registry.ts b/src/realtime-transcription/provider-registry.ts
index 0f66570b40b..ed8b6785370 100644
--- a/src/realtime-transcription/provider-registry.ts
+++ b/src/realtime-transcription/provider-registry.ts
@@ -1,13 +1,16 @@
 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 type { RealtimeTranscriptionProviderPlugin } from "../plugins/types.js";
-import { normalizeOptionalString } from "../shared/string-coerce.js";
 import type { RealtimeTranscriptionProviderId } from "./provider-types.js";
 
 export function normalizeRealtimeTranscriptionProviderId(
   providerId: string | undefined,
 ): RealtimeTranscriptionProviderId | undefined {
-  return normalizeOptionalString(providerId)?.toLowerCase();
+  return normalizeCapabilityProviderId(providerId);
 }
 
 function resolveRealtimeTranscriptionProviderEntries(
@@ -23,28 +26,7 @@ function buildProviderMaps(cfg?: OpenClawConfig): {
   canonical: Map<string, RealtimeTranscriptionProviderPlugin>;
   aliases: Map<string, RealtimeTranscriptionProviderPlugin>;
 } {
-  const canonical = new Map<string, RealtimeTranscriptionProviderPlugin>();
-  const aliases = new Map<string, RealtimeTranscriptionProviderPlugin>();
-  const register = (provider: RealtimeTranscriptionProviderPlugin) => {
-    const id = normalizeRealtimeTranscriptionProviderId(provider.id);
-    if (!id) {
-      return;
-    }
-    canonical.set(id, provider);
-    aliases.set(id, provider);
-    for (const alias of provider.aliases ?? []) {
-      const normalizedAlias = normalizeRealtimeTranscriptionProviderId(alias);
-      if (normalizedAlias) {
-        aliases.set(normalizedAlias, provider);
-      }
-    }
-  };
-
-  for (const provider of resolveRealtimeTranscriptionProviderEntries(cfg)) {
-    register(provider);
-  }
-
-  return { canonical, aliases };
+  return buildCapabilityProviderMaps(resolveRealtimeTranscriptionProviderEntries(cfg));
 }
 
 export function listRealtimeTranscriptionProviders(
diff --git a/src/realtime-voice/provider-registry.ts b/src/realtime-voice/provider-registry.ts
index ef5304e0665..c7146580b79 100644
--- a/src/realtime-voice/provider-registry.ts
+++ b/src/realtime-voice/provider-registry.ts
@@ -1,14 +1,16 @@
 import type { OpenClawConfig } from "../config/config.js";
 import { resolvePluginCapabilityProviders } from "../plugins/capability-provider-runtime.js";
-import { buildCapabilityProviderMaps } from "../plugins/provider-registry-shared.js";
+import {
+  buildCapabilityProviderMaps,
+  normalizeCapabilityProviderId,
+} 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 normalizeOptionalString(providerId)?.toLowerCase();
+  return normalizeCapabilityProviderId(providerId);
 }
 
 function resolveRealtimeVoiceProviderEntries(cfg?: OpenClawConfig): RealtimeVoiceProviderPlugin[] {
diff --git a/src/tts/provider-registry.ts b/src/tts/provider-registry.ts
index bd7d84b5103..1b9f3041499 100644
--- a/src/tts/provider-registry.ts
+++ b/src/tts/provider-registry.ts
@@ -1,14 +1,16 @@
 import type { OpenClawConfig } from "../config/config.js";
 import { resolvePluginCapabilityProviders } from "../plugins/capability-provider-runtime.js";
-import { buildCapabilityProviderMaps } from "../plugins/provider-registry-shared.js";
+import {
+  buildCapabilityProviderMaps,
+  normalizeCapabilityProviderId,
+} 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 normalizeOptionalString(providerId)?.toLowerCase();
+  return normalizeCapabilityProviderId(providerId);
 }
 
 function resolveSpeechProviderPluginEntries(cfg?: OpenClawConfig): SpeechProviderPlugin[] {