[pull] main from microsoft:main

.agents/skills/launch/scripts/launch.ps1

@@ -506,7 +506,8 @@ try {
 	if ($agents) {
 		$launchArgs.Add('--agents')
 		if (-not [string]::IsNullOrWhiteSpace($sessionTitle)) {
-			$launchArgs.Add("--session-title=$sessionTitle")
+			$sessionTitleBase64 = [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes($sessionTitle)).TrimEnd('=').Replace('+', '-').Replace('/', '_')
+			$launchArgs.Add("--session-title-base64=$sessionTitleBase64")
 		}
 	}
 	$launchArgs.Add("--user-data-dir=$destinationUdd")

.agents/skills/launch/scripts/launch.sh

@@ -221,7 +221,8 @@ fi
 if [[ "$AGENTS" == "1" ]]; then
 	ARGS=("--agents" "${ARGS[@]}")
 	if [[ -n "$SESSION_TITLE" ]]; then
-		ARGS+=("--session-title=$SESSION_TITLE")
+		SESSION_TITLE_BASE64=$(node -e 'process.stdout.write(Buffer.from(process.argv[1], "utf8").toString("base64url"))' -- "$SESSION_TITLE")
+		ARGS+=("--session-title-base64=$SESSION_TITLE_BASE64")
 	fi
 fi
 if (( ${#EXTRA_ARGS[@]} )); then

build/lib/policies/policyData.jsonc

@@ -220,6 +220,21 @@
             "default": false,
             "included": true
         },
+        {
+            "key": "chat.agentHost.customTerminalTool.enabled",
+            "name": "ChatAgentHostCustomTerminalTool",
+            "category": "InteractiveSession",
+            "minimumVersion": "1.137",
+            "localization": {
+                "description": {
+                    "key": "chat.agentHost.customTerminalTool.enabled.policy",
+                    "value": "Enable the Agent Host custom terminal tool override for Copilot SDK sessions."
+                }
+            },
+            "type": "boolean",
+            "default": false,
+            "included": true
+        },
         {
             "key": "chat.agentHost.otel.captureContent",
             "name": "CopilotOtelCaptureContent",

extensions/bat/language-configuration.json

@@ -1,6 +1,6 @@
 {
 	"comments": {
-		"lineComment": "@REM"
+		"lineComment": "@REM "
 	},
 	"brackets": [
 		["{", "}"],

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

@@ -298,9 +298,12 @@ Learn more about [GitHub Copilot](https://docs.github.com/copilot/using-github-c
 		if (!baseLmModel) {
 			return request;
 		}
-		await vscode.commands.executeCommand('workbench.action.chat.changeModel', { vendor: baseLmModel.vendor, id: baseLmModel.id, family: baseLmModel.family });
-		// Switch to the base model and show a warning
 		request = { ...request, model: baseLmModel };
+		if (request.subAgentInvocationId === undefined) {
+			// A subagent runs inside the main request; changing the picker there would flip every widget mid-turn.
+			await vscode.commands.executeCommand('workbench.action.chat.changeModel', { vendor: baseLmModel.vendor, id: baseLmModel.id, family: baseLmModel.family });
+		}
+		// Switch to the base model and show a warning
 		let messageString: vscode.MarkdownString;
 		if (this.authenticationService.copilotToken?.isIndividual) {
 			messageString = new vscode.MarkdownString(vscode.l10n.t({
@@ -322,8 +325,10 @@ Learn more about [GitHub Copilot](https://docs.github.com/copilot/using-github-c
 		if (!autoModel) {
 			return request;
 		}
-		await vscode.commands.executeCommand('workbench.action.chat.changeModel', { vendor: autoModel.vendor, id: autoModel.id, family: autoModel.family });
 		request = { ...request, model: autoModel };
+		if (request.subAgentInvocationId === undefined) {
+			await vscode.commands.executeCommand('workbench.action.chat.changeModel', { vendor: autoModel.vendor, id: autoModel.id, family: autoModel.family });
+		}
 		if (alwaysSwitchToAuto) {
 			await vscode.workspace.getConfiguration('github.copilot').update('chat.rateLimitAutoSwitchToAuto', true, vscode.ConfigurationTarget.Global);
 		}

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

@@ -158,6 +158,7 @@ function buildConfigurationSchema(endpoint: IChatEndpoint, autoTiersEnabled: boo
 
 const DICTATION_CLEANUP_NANO_ALIAS = 'copilot-dictation-cleanup-nano';
 const DICTATION_CLEANUP_LUNA_ALIAS = 'copilot-dictation-cleanup-luna';
+const DICTATION_CLEANUP_LUNA_MODEL_ID = 'gpt-5.6-luna';
 const dictationCleanupAliases: ReadonlySet<string> = new Set([DICTATION_CLEANUP_NANO_ALIAS, DICTATION_CLEANUP_LUNA_ALIAS]);
 const utilityAliasFamilies: readonly ChatEndpointFamily[] = ['copilot-utility-small', 'copilot-utility', DICTATION_CLEANUP_NANO_ALIAS, DICTATION_CLEANUP_LUNA_ALIAS];
 
@@ -175,7 +176,7 @@ const utilityAliasFamilies: readonly ChatEndpointFamily[] = ['copilot-utility-sm
  * normal copilot model entry.
  */
 export function buildUtilityAliasModelInfo(
-	family: ChatEndpointFamily,
+	family: string,
 	endpoint: IChatEndpoint,
 	models: readonly vscode.LanguageModelChatInformation[],
 	baseCount: number,
@@ -453,6 +454,14 @@ export class LanguageModelAccess extends Disposable implements IExtensionContrib
 			}
 		}
 
+		const luna = this._resolvedUtilityEndpoints.get(DICTATION_CLEANUP_LUNA_ALIAS);
+		if (luna && !models.some(model => model.id === DICTATION_CLEANUP_LUNA_MODEL_ID)) {
+			this._utilityAliasEndpoints.set(DICTATION_CLEANUP_LUNA_MODEL_ID, luna.endpoint);
+			const modelInfo = buildUtilityAliasModelInfo(DICTATION_CLEANUP_LUNA_MODEL_ID, luna.endpoint, models, luna.baseCount, requiresAuthorization);
+			this._logService.trace(`[LanguageModelAccess] Publishing core-only model '${DICTATION_CLEANUP_LUNA_MODEL_ID}' -> ${luna.endpoint.model}.`);
+			models.push(modelInfo.info);
+		}
+
 		// Resolution may hang (override lookups, base-count tokenization), so keep it off
 		// the model-info request path. Newly resolved endpoints are published on the next
 		// request once `_refreshUtilityOverrides` fires `_onDidChange`.
@@ -546,7 +555,8 @@ export class LanguageModelAccess extends Disposable implements IExtensionContrib
 		progress: vscode.Progress<vscode.LanguageModelResponsePart2>,
 		token: vscode.CancellationToken
 	): Promise<void> {
-		if (dictationCleanupAliases.has(model.id) && options.requestInitiator !== 'core') {
+		const isCoreOnlyModel = dictationCleanupAliases.has(model.id) || (model.id === DICTATION_CLEANUP_LUNA_MODEL_ID && this._utilityAliasEndpoints.has(model.id));
+		if (isCoreOnlyModel && options.requestInitiator !== 'core') {
 			throw new Error(`Model ${model.id} is only available to VS Code core.`);
 		}
 		let endpoint = await this._getEndpointForModel(model, buildAutoRoutingContext(messages, options));

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

@@ -437,7 +437,7 @@ suite('LanguageModelAccess model info', () => {
 		}
 	});
 
-	test('publishes core-only aliases for dictation cleanup without publishing hidden models directly', async () => {
+	test('publishes core-only dictation cleanup models without exposing them in the picker', async () => {
 		const makeHiddenEndpoint = (model: string): IChatEndpoint => ({
 			model,
 			name: model,
@@ -510,27 +510,30 @@ suite('LanguageModelAccess model info', () => {
 			assert.ok(modelInfo, 'provideLanguageModelChatInfo did not resolve');
 			const nanoAlias = modelInfo.find(m => m.id === 'copilot-dictation-cleanup-nano');
 			const lunaAlias = modelInfo.find(m => m.id === 'copilot-dictation-cleanup-luna');
+			const lunaModel = modelInfo.find(m => m.id === 'gpt-5.6-luna');
 			assert.deepStrictEqual({
 				nanoAliasPublished: Boolean(nanoAlias),
 				nanoAliasUserSelectable: nanoAlias?.isUserSelectable,
 				lunaAliasPublished: Boolean(lunaAlias),
 				lunaAliasUserSelectable: lunaAlias?.isUserSelectable,
 				nanoPublishedDirectly: modelInfo.some(m => m.id === 'gpt-5.4-nano'),
-				lunaPublishedDirectly: modelInfo.some(m => m.id === 'gpt-5.6-luna'),
+				lunaPublishedDirectly: Boolean(lunaModel),
+				lunaDirectlyUserSelectable: lunaModel?.isUserSelectable,
 				otherPublished: modelInfo.some(m => m.id === 'some-hidden-model'),
 			}, {
 				nanoAliasPublished: true,
 				nanoAliasUserSelectable: false,
 				lunaAliasPublished: true,
 				lunaAliasUserSelectable: false,
 				nanoPublishedDirectly: false,
-				lunaPublishedDirectly: false,
+				lunaPublishedDirectly: true,
+				lunaDirectlyUserSelectable: false,
 				otherPublished: false,
 			});
-			for (const alias of [nanoAlias!, lunaAlias!]) {
+			for (const model of [nanoAlias!, lunaAlias!, lunaModel!]) {
 				await assert.rejects(
 					testAccess._provideLanguageModelChatResponse(
-						alias,
+						model,
 						[],
 						{ requestInitiator: 'publisher.extension' } as vscode.ProvideLanguageModelChatResponseOptions,
 						{ report: () => { } },