diff --git a/extensions/copilot/src/extension/byok/vscode-node/azureProvider.ts b/extensions/copilot/src/extension/byok/vscode-node/azureProvider.ts
index 76933c489b4..0287f7ff0be 100644
--- a/extensions/copilot/src/extension/byok/vscode-node/azureProvider.ts
+++ b/extensions/copilot/src/extension/byok/vscode-node/azureProvider.ts
@@ -10,7 +10,7 @@ import { IInstantiationService } from '../../../util/vs/platform/instantiation/c
 import { IBYOKStorageService } from './byokStorageService';
 import { CustomOAIBYOKModelProvider, hasExplicitApiPath } from './customOAIProvider';
 
-export function resolveAzureUrl(modelId: string, url: string): string {
+export function resolveAzureUrl(modelId: string, url: string, useResponsesApi: boolean = false): string {
 	// The fully resolved url was already passed in
 	if (hasExplicitApiPath(url)) {
 		return url;
@@ -26,9 +26,14 @@ export function resolveAzureUrl(modelId: string, url: string): string {
 	}
 
 	if (url.includes('models.ai.azure.com') || url.includes('inference.ml.azure.com')) {
-		return `${url}/v1/chat/completions`;
+		const apiPath = useResponsesApi ? '/v1/responses' : '/v1/chat/completions';
+		return `${url}${apiPath}`;
 	} else if (url.includes('openai.azure.com')) {
-		return `${url}/openai/deployments/${modelId}/chat/completions?api-version=2025-01-01-preview`;
+		if (useResponsesApi) {
+			return `${url}/openai/v1/responses`;
+		} else {
+			return `${url}/openai/deployments/${modelId}/chat/completions?api-version=2025-01-01-preview`;
+		}
 	} else {
 		throw new Error(`Unrecognized Azure deployment URL: ${url}`);
 	}
@@ -59,7 +64,7 @@ export class AzureBYOKModelProvider extends CustomOAIBYOKModelProvider {
 		return ConfigKey.AzureModels;
 	}
 
-	protected override resolveUrl(modelId: string, url: string): string {
-		return resolveAzureUrl(modelId, url);
+	protected override resolveUrl(modelId: string, url: string, useResponsesApi?: boolean): string {
+		return resolveAzureUrl(modelId, url, useResponsesApi);
 	}
 }
diff --git a/extensions/copilot/src/extension/byok/vscode-node/customOAIProvider.ts b/extensions/copilot/src/extension/byok/vscode-node/customOAIProvider.ts
index 2c54b68914c..961a4ba3a44 100644
--- a/extensions/copilot/src/extension/byok/vscode-node/customOAIProvider.ts
+++ b/extensions/copilot/src/extension/byok/vscode-node/customOAIProvider.ts
@@ -16,7 +16,7 @@ import { IBYOKStorageService } from './byokStorageService';
 import { promptForAPIKey } from './byokUIService';
 import { CustomOAIModelConfigurator } from './customOAIModelConfigurator';
 
-export function resolveCustomOAIUrl(modelId: string, url: string): string {
+export function resolveCustomOAIUrl(modelId: string, url: string, useResponsesApi: boolean = false): string {
 	// The fully resolved url was already passed in
 	if (hasExplicitApiPath(url)) {
 		return url;
@@ -27,14 +27,16 @@ export function resolveCustomOAIUrl(modelId: string, url: string): string {
 		url = url.slice(0, -1);
 	}
 
+	const apiPath = useResponsesApi ? '/responses' : '/chat/completions';
+
 	// Check if URL already contains any version pattern like /v1, /v2, etc
 	const versionPattern = /\/v\d+$/;
 	if (versionPattern.test(url)) {
-		return `${url}/chat/completions`;
+		return `${url}${apiPath}`;
 	}
 
 	// For standard OpenAI-compatible endpoints, just append the standard path
-	return `${url}/v1/chat/completions`;
+	return `${url}/v1${apiPath}`;
 }
 
 export function hasExplicitApiPath(url: string): boolean {
@@ -68,14 +70,13 @@ export class CustomOAIBYOKModelProvider implements BYOKModelProvider<CustomOAIMo
 		return ConfigKey.CustomOAIModels;
 	}
 
-	protected resolveUrl(modelId: string, url: string): string {
-		return resolveCustomOAIUrl(modelId, url);
+	protected resolveUrl(modelId: string, url: string, useResponsesApi?: boolean): string {
+		return resolveCustomOAIUrl(modelId, url, useResponsesApi);
 	}
 
 	protected async getModelInfo(modelId: string, apiKey: string | undefined, modelCapabilities?: BYOKModelCapabilities): Promise<IChatModelInformation> {
 		const modelInfo = await resolveModelInfo(modelId, this.providerName, undefined, modelCapabilities);
-		const enableResponsesApi = this._configurationService.getExperimentBasedConfig(ConfigKey.UseResponsesApi, this._experimentationService);
-		if (enableResponsesApi) {
+		if (modelCapabilities?.url?.includes('/responses')) {
 			modelInfo.supported_endpoints = [
 				ModelSupportedEndpoint.ChatCompletions,
 				ModelSupportedEndpoint.Responses
@@ -100,12 +101,9 @@ export class CustomOAIBYOKModelProvider implements BYOKModelProvider<CustomOAIMo
 		const enableResponsesApi = this._configurationService.getExperimentBasedConfig(ConfigKey.UseResponsesApi, this._experimentationService);
 
 		for (const [modelId, modelInfo] of Object.entries(modelConfig)) {
-			let resolvedUrl = this.resolveUrl(modelId, modelInfo.url);
-
-			// If user didn't specify explicit endpoint and Responses API is enabled, use Responses API
-			if (!hasExplicitApiPath(modelInfo.url) && enableResponsesApi && resolvedUrl.includes('/chat/completions')) {
-				resolvedUrl = resolvedUrl.replace('/chat/completions', '/responses');
-			}
+			// Only use Responses API if user explicitly specified /responses OR experiment is enabled (for base URLs only)
+			const useResponsesApi = modelInfo.url.includes('/responses') || (!hasExplicitApiPath(modelInfo.url) && enableResponsesApi);
+			const resolvedUrl = this.resolveUrl(modelId, modelInfo.url, useResponsesApi);
 
 			models[modelId] = {
 				name: modelInfo.name,