diff --git a/api/models/Agent.js b/api/models/Agent.js
index b624f1430d..fd71ef282c 100644
--- a/api/models/Agent.js
+++ b/api/models/Agent.js
@@ -8,7 +8,6 @@ const {
   ResourceType,
   actionDelimiter,
   isAgentsEndpoint,
-  getResponseSender,
   isEphemeralAgentId,
   encodeEphemeralAgentId,
 } = require('librechat-data-provider');
@@ -150,7 +149,7 @@ const loadEphemeralAgent = async ({ req, spec, endpoint, model_parameters: _m })
 
   const instructions = req.body.promptPrefix;
 
-  // Compute display name using getResponseSender (same logic used for addedConvo agents)
+  // Get endpoint config for modelDisplayLabel fallback
   const appConfig = req.config;
   let endpointConfig = appConfig?.endpoints?.[endpoint];
   if (!isAgentsEndpoint(endpoint) && !endpointConfig) {
@@ -161,10 +160,10 @@ const loadEphemeralAgent = async ({ req, spec, endpoint, model_parameters: _m })
     }
   }
 
-  const sender = getResponseSender({
-    modelLabel: model_parameters?.modelLabel,
-    modelDisplayLabel: endpointConfig?.modelDisplayLabel,
-  });
+  // For ephemeral agents, use modelLabel if provided, then model spec's label,
+  // then modelDisplayLabel from endpoint config, otherwise empty string to show model name
+  const sender =
+    model_parameters?.modelLabel ?? modelSpec?.label ?? endpointConfig?.modelDisplayLabel ?? '';
 
   // Encode ephemeral agent ID with endpoint, model, and computed sender for display
   const ephemeralId = encodeEphemeralAgentId({ endpoint, model, sender });
diff --git a/api/models/loadAddedAgent.js b/api/models/loadAddedAgent.js
index 1678b2a558..aa83375eae 100644
--- a/api/models/loadAddedAgent.js
+++ b/api/models/loadAddedAgent.js
@@ -4,7 +4,6 @@ const {
   Tools,
   Constants,
   isAgentsEndpoint,
-  getResponseSender,
   isEphemeralAgentId,
   appendAgentIdSuffix,
   encodeEphemeralAgentId,
@@ -81,7 +80,7 @@ const loadAddedAgent = async ({ req, conversation, primaryAgent }) => {
   // If both primary and added agents are ephemeral, duplicate tools from primary agent
   const primaryIsEphemeral = primaryAgent && isEphemeralAgentId(primaryAgent.id);
   if (primaryIsEphemeral && Array.isArray(primaryAgent.tools)) {
-    // Get display name using getResponseSender
+    // Get endpoint config and model spec for display name fallbacks
     const appConfig = req.config;
     let endpointConfig = appConfig?.endpoints?.[endpoint];
     if (!isAgentsEndpoint(endpoint) && !endpointConfig) {
@@ -92,10 +91,13 @@ const loadAddedAgent = async ({ req, conversation, primaryAgent }) => {
       }
     }
 
-    const sender = getResponseSender({
-      modelLabel: rest.modelLabel,
-      modelDisplayLabel: endpointConfig?.modelDisplayLabel,
-    });
+    // Look up model spec for label fallback
+    const modelSpecs = appConfig?.modelSpecs?.list;
+    const modelSpec = spec != null && spec !== '' ? modelSpecs?.find((s) => s.name === spec) : null;
+
+    // For ephemeral agents, use modelLabel if provided, then model spec's label,
+    // then modelDisplayLabel from endpoint config, otherwise empty string to show model name
+    const sender = rest.modelLabel ?? modelSpec?.label ?? endpointConfig?.modelDisplayLabel ?? '';
 
     const ephemeralId = encodeEphemeralAgentId({ endpoint, model, sender, index: 1 });
 
@@ -175,7 +177,7 @@ const loadAddedAgent = async ({ req, conversation, primaryAgent }) => {
     }
   }
 
-  // Get endpoint config for modelDisplayLabel (same pattern as initialize.js)
+  // Get endpoint config for modelDisplayLabel fallback
   const appConfig = req.config;
   let endpointConfig = appConfig?.endpoints?.[endpoint];
   if (!isAgentsEndpoint(endpoint) && !endpointConfig) {
@@ -186,11 +188,9 @@ const loadAddedAgent = async ({ req, conversation, primaryAgent }) => {
     }
   }
 
-  // Compute display name using getResponseSender (same logic used for main agent)
-  const sender = getResponseSender({
-    modelLabel: rest.modelLabel,
-    modelDisplayLabel: endpointConfig?.modelDisplayLabel,
-  });
+  // For ephemeral agents, use modelLabel if provided, then model spec's label,
+  // then modelDisplayLabel from endpoint config, otherwise empty string to show model name
+  const sender = rest.modelLabel ?? modelSpec?.label ?? endpointConfig?.modelDisplayLabel ?? '';
 
   /** Encoded ephemeral agent ID with endpoint, model, sender, and index=1 to distinguish from primary */
   const ephemeralId = encodeEphemeralAgentId({ endpoint, model, sender, index: 1 });
diff --git a/client/src/hooks/Chat/useChatFunctions.ts b/client/src/hooks/Chat/useChatFunctions.ts
index 513688c9d3..8479d8eaac 100644
--- a/client/src/hooks/Chat/useChatFunctions.ts
+++ b/client/src/hooks/Chat/useChatFunctions.ts
@@ -18,6 +18,7 @@ import type {
   TMessage,
   TSubmission,
   TConversation,
+  TStartupConfig,
   TEndpointOption,
   TEndpointsConfig,
   EndpointSchemaKey,
@@ -169,6 +170,7 @@ export default function useChatFunctions({
     }
 
     const endpointsConfig = queryClient.getQueryData<TEndpointsConfig>([QueryKeys.endpoints]);
+    const startupConfig = queryClient.getQueryData<TStartupConfig>([QueryKeys.startupConfig]);
     const endpointType = getEndpointField(endpointsConfig, endpoint, 'type');
     const iconURL = conversation?.iconURL;
 
@@ -291,6 +293,7 @@ export default function useChatFunctions({
           conversation,
           addedConvo,
           endpointsConfig,
+          startupConfig?.modelSpecs?.list,
         );
       } else {
         initialResponse.content = [];
diff --git a/client/src/utils/messages.ts b/client/src/utils/messages.ts
index 2bffe2177c..7197b6c2db 100644
--- a/client/src/utils/messages.ts
+++ b/client/src/utils/messages.ts
@@ -2,7 +2,6 @@ import {
   QueryKeys,
   Constants,
   ContentTypes,
-  getResponseSender,
   isEphemeralAgentId,
   appendAgentIdSuffix,
   encodeEphemeralAgentId,
@@ -199,12 +198,14 @@ export const getMessageAriaLabel = (message: TMessage, localize: LocalizeFunctio
  * @param primaryConvo - The primary conversation configuration
  * @param addedConvo - The added conversation configuration
  * @param endpointsConfig - Endpoints configuration for getting model display labels
+ * @param modelSpecs - Model specs list for getting spec labels
  * @returns Array of content parts with agentId for side-by-side rendering
  */
 export const createDualMessageContent = (
   primaryConvo: TConversation,
   addedConvo: TConversation,
   endpointsConfig?: TEndpointsConfig,
+  modelSpecs?: { name: string; label?: string }[],
 ): TMessageContentParts[] => {
   // For real agents (agent_id starts with "agent_"), use agent_id directly
   // Otherwise create ephemeral ID from endpoint/model
@@ -214,11 +215,18 @@ export const createDualMessageContent = (
   } else {
     const primaryEndpoint = primaryConvo.endpoint;
     const primaryModel = primaryConvo.model ?? '';
-    const primarySender = getResponseSender({
-      modelDisplayLabel: primaryEndpoint
-        ? endpointsConfig?.[primaryEndpoint]?.modelDisplayLabel
-        : undefined,
-    });
+    // Look up model spec for label fallback
+    const primarySpec =
+      primaryConvo.spec != null && primaryConvo.spec !== ''
+        ? modelSpecs?.find((s) => s.name === primaryConvo.spec)
+        : undefined;
+    // For ephemeral agents, use modelLabel if provided, then model spec's label,
+    // then modelDisplayLabel from endpoint config, otherwise empty string to show model name
+    const primarySender =
+      primaryConvo.modelLabel ??
+      primarySpec?.label ??
+      (primaryEndpoint ? endpointsConfig?.[primaryEndpoint]?.modelDisplayLabel : undefined) ??
+      '';
     primaryAgentId = encodeEphemeralAgentId({
       endpoint: primaryEndpoint ?? '',
       model: primaryModel,
@@ -247,11 +255,18 @@ export const createDualMessageContent = (
   } else {
     const addedEndpoint = addedConvo.endpoint;
     const addedModel = addedConvo.model ?? '';
-    const addedSender = addedEndpoint
-      ? getResponseSender({
-          modelDisplayLabel: endpointsConfig?.[addedEndpoint]?.modelDisplayLabel,
-        })
-      : '';
+    // Look up model spec for label fallback
+    const addedSpec =
+      addedConvo.spec != null && addedConvo.spec !== ''
+        ? modelSpecs?.find((s) => s.name === addedConvo.spec)
+        : undefined;
+    // For ephemeral agents, use modelLabel if provided, then model spec's label,
+    // then modelDisplayLabel from endpoint config, otherwise empty string to show model name
+    const addedSender =
+      addedConvo.modelLabel ??
+      addedSpec?.label ??
+      (addedEndpoint ? endpointsConfig?.[addedEndpoint]?.modelDisplayLabel : undefined) ??
+      '';
     addedAgentId = encodeEphemeralAgentId({
       endpoint: addedEndpoint ?? '',
       model: addedModel,