Skip effort picker when only one reasoning effort level exists (#309934)

* Skip effort picker when only one reasoning effort level exists

* Handle single reasoning effort level in createMessagesRequestBody

* Apply suggestion from @sbatten

---------

Co-authored-by: SteVen Batten <sbatten@microsoft.com>

Author: bhavyaus

extensions/copilot/src/extension/conversation/vscode-node/languageModelAccess.ts

@@ -56,7 +56,7 @@ const experimentalAutoModelHintMarkers = ['minimax', 'mp3yn0h7', 'yaqq2gxh'];
  */
 function buildConfigurationSchema(endpoint: IChatEndpoint): { configurationSchema?: vscode.LanguageModelConfigurationSchema } {
 	const effortLevels = endpoint.supportsReasoningEffort;
-	if (!effortLevels || effortLevels.length === 0) {
+	if (!effortLevels || effortLevels.length <= 1) {
 		return {};
 	}
 

extensions/copilot/src/platform/endpoint/node/messagesApi.ts

@@ -167,7 +167,9 @@ export function createMessagesRequestBody(accessor: ServicesAccessor, options: I
 	const thinkingEnabled = !!thinkingConfig;
 	let effort: 'low' | 'medium' | 'high' | undefined;
 	if (thinkingConfig && endpoint.supportsReasoningEffort?.length) {
-		const candidateEffort = configurationService.getConfig(ConfigKey.TeamInternal.AnthropicThinkingEffort) ?? reasoningEffort;
+		const candidateEffort = configurationService.getConfig(ConfigKey.TeamInternal.AnthropicThinkingEffort)
+			?? reasoningEffort
+			?? (endpoint.supportsReasoningEffort.length === 1 ? endpoint.supportsReasoningEffort[0] : 'medium');
 		if (candidateEffort === 'low' || candidateEffort === 'medium' || candidateEffort === 'high') {
 			effort = candidateEffort;
 		}