agentHost: switch Auto routing preferences with the SDK

extensions/copilot/package.json

@@ -4406,17 +4406,6 @@
               "advanced"
             ]
           },
-          "github.copilot.chat.autoModeTierOverride": {
-            "type": [
-              "string",
-              "null"
-            ],
-            "default": null,
-            "markdownDescription": "Overrides the routing tier that the `Auto` model requests, ignoring both the tier picked in the model picker and the tier inline chat defaults to. Accepts `efficiency`, `balance`, `intelligence`, or `fast`. Used by evals.\n\n**Note**: This is an advanced debugging setting.",
-            "tags": [
-              "advanced"
-            ]
-          },
           "github.copilot.chat.anthropic.promptCaching.extendedTtl": {
             "type": "boolean",
             "default": false,
@@ -5089,15 +5078,6 @@
               "advanced"
             ]
           },
-          "github.copilot.chat.autoMode.tiers.enabled": {
-            "type": "boolean",
-            "default": false,
-            "markdownDescription": "%github.copilot.config.chat.autoMode.tiers.enabled%",
-            "tags": [
-              "advanced",
-              "onExp"
-            ]
-          },
           "github.copilot.chat.agent.modelDetails.enabled": {
             "type": "boolean",
             "default": true,

extensions/copilot/package.nls.json

@@ -424,7 +424,6 @@
 	"github.copilot.config.cli.forkSessions.enabled": "Enable forking sessions in Copilot CLI.",
 	"github.copilot.config.cli.planExitMode.enabled": "Enable Plan Mode exit handling in Copilot CLI.",
 	"github.copilot.config.cli.autoModel.enabled": "Enable the Auto model option in Copilot CLI, which automatically selects the best model for each request. Requires VS Code reload.",
-	"github.copilot.config.chat.autoMode.tiers.enabled": "Choose a routing tier for the Auto model, biasing model selection toward cost, capability, or speed. When disabled, the service picks the routing profile.",
 	"github.copilot.config.chat.agent.modelDetails.enabled": "Show model details (model name and request multiplier) on Copilot CLI agent chat responses. Requires VS Code reload to update already loaded sessions.",
 	"github.copilot.config.cli.planCommand.enabled": "Enable the /plan command in Copilot CLI to create implementation plans before coding.",
 	"github.copilot.config.cli.lazyLoadSessionItem.enabled": "Enable lazy loading of session items in Copilot CLI. Requires VS Code reload.",

extensions/copilot/src/platform/configuration/common/configurationService.ts

@@ -698,11 +698,7 @@ export const XTabProviderId = 'XtabProvider';
 
 export namespace ConfigKey {
 
-	/**
-	 * These settings are defined in the completions extensions and shared.
-	 *
-	 * We should not change the names of these settings without coordinating with Completions extension.
-	*/
+	/** Settings owned by VS Code or the completions extension; coordinate identifier changes with their owner. */
 	export namespace Shared {
 		/** Allows for overriding the base domain we use for making requests to the CAPI. This helps CAPI devs develop against a local instance. */
 		export const DebugOverrideProxyUrl = defineSetting<string | undefined>('advanced.debug.overrideProxyUrl', ConfigType.Simple, undefined, undefined, { userScopeOnly: true });
@@ -715,6 +711,10 @@ export namespace ConfigKey {
 		export const DebugNodeFetchCache = defineSetting<'off' | 'memory' | 'persistent'>('advanced.debug.nodeFetchCache', ConfigType.Simple, 'memory');
 		export const AuthProvider = defineSetting<AuthProviderId>('advanced.authProvider', ConfigType.Simple, AuthProviderId.GitHub);
 		export const AuthPermissions = defineSetting<AuthPermissionMode>('advanced.authPermissions', ConfigType.Simple, AuthPermissionMode.Default);
+		/** The workbench owns the experiment default so all Auto pickers read the same effective setting. */
+		export const AutoModeTiersEnabled = defineSetting<boolean>('chat.autoMode.tiers.enabled', ConfigType.Simple, false);
+		/** Override Auto's "Optimize for" preference in both harnesses; the extension additionally accepts `fast`. */
+		export const AutoModeTierOverride = defineSetting<string | null>('chat.autoModeTierOverride', ConfigType.Simple, null);
 	}
 
 	/**
@@ -746,11 +746,6 @@ export namespace ConfigKey {
 		export const OmitBaseAgentInstructions = defineAndMigrateSetting<boolean>('chat.advanced.omitBaseAgentInstructions', 'chat.omitBaseAgentInstructions', false);
 		export const CLIPlanExitModeEnabled = defineSetting<boolean>('chat.cli.planExitMode.enabled', ConfigType.Simple, true);
 		export const CLIAutoModelEnabled = defineSetting<boolean>('chat.cli.autoModel.enabled', ConfigType.Simple, true);
-		/**
-		 * Offer routing tiers on the Auto model. Off by default: while disabled
-		 * no tier is sent and the server picks its own routing profile.
-		 */
-		export const AutoModeTiersEnabled = defineSetting<boolean>('chat.autoMode.tiers.enabled', ConfigType.ExperimentBased, false, undefined, undefined, { experimentName: 'copilotchat.autoModeTiersEnabled' });
 		export const CLIModelDetailsEnabled = defineSetting<boolean>('chat.agent.modelDetails.enabled', ConfigType.Simple, true);
 		export const CLIPlanCommandEnabled = defineSetting<boolean>('chat.cli.planCommand.enabled', ConfigType.Simple, true);
 		export const CLIChatLazyLoadSessionItem = defineSetting<boolean>('chat.cli.lazyLoadSessionItem.enabled', ConfigType.Simple, true);
@@ -871,13 +866,6 @@ export namespace ConfigKey {
 		export const ReasoningEffortOverride = defineSetting<string | null>('chat.reasoningEffortOverride', ConfigType.Simple, null);
 		export const ChatCompletionsTokenParameter = defineSetting('chat.chatCompletionsTokenParameter', ConfigType.ExperimentBased, 'max_tokens', vEnum('max_completion_tokens', 'max_tokens'));
 
-		/**
-		 * Internal: override the routing tier sent to `POST /auto`, ignoring both the
-		 * model picker and the tier inline chat defaults to. Unlike the picker this
-		 * accepts `fast`, so evals can exercise every profile.
-		 */
-		export const AutoModeTierOverride = defineSetting<string | null>('chat.autoModeTierOverride', ConfigType.Simple, null);
-
 		/**
 		 * When enabled, periodic keep-alive probes are sent during long-running tool calls
 		 * to keep the server-side prompt cache warm.

extensions/copilot/src/platform/endpoint/common/autoModeTiers.ts

@@ -15,7 +15,7 @@ export type AutoModeTier = typeof autoModeTiers[number];
  * The tiers offered in the model picker. `fast` is excluded: it is the profile
  * inline chat falls back to when the user has not picked a tier, and is not
  * offered as a choice. It remains reachable through the internal
- * {@link ConfigKey.Advanced.AutoModeTierOverride} setting.
+ * {@link ConfigKey.Shared.AutoModeTierOverride} setting.
  */
 export const selectableAutoModeTiers: readonly AutoModeTier[] = ['efficiency', 'balance', 'intelligence'];
 

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

@@ -16,7 +16,6 @@ import { ILogService } from '../../log/common/logService';
 import { isAbortError } from '../../networking/common/fetcherService';
 import { IChatEndpoint } from '../../networking/common/networking';
 import { IRequestLogger } from '../../requestLogger/common/requestLogger';
-import { IExperimentationService } from '../../telemetry/common/nullExperimentationService';
 import { ITelemetryService } from '../../telemetry/common/telemetry';
 import { AUTO_MODE_TIER_PROPERTY, autoModeTiers, defaultAutoModeTier, inlineChatAutoModeTier, isSelectableAutoModeTier, normalizeAutoModeTier, type AutoModeTier } from '../common/autoModeTiers';
 import { ICAPIClientService } from '../common/capiClient';
@@ -162,7 +161,6 @@ export class AutomodeService extends Disposable implements IAutomodeService {
 		@IAuthenticationService private readonly _authService: IAuthenticationService,
 		@ILogService private readonly _logService: ILogService,
 		@IInstantiationService private readonly _instantiationService: IInstantiationService,
-		@IExperimentationService private readonly _expService: IExperimentationService,
 		@ITelemetryService private readonly _telemetryService: ITelemetryService,
 		@IRequestLogger private readonly _requestLogger: IRequestLogger,
 		@IConfigurationService private readonly _configurationService: IConfigurationService,
@@ -364,7 +362,7 @@ export class AutomodeService extends Disposable implements IAutomodeService {
 	}
 
 	areAutoModeTiersSupported(): boolean {
-		return this._configurationService.getExperimentBasedConfig(ConfigKey.Advanced.AutoModeTiersEnabled, this._expService);
+		return this._configurationService.getConfig(ConfigKey.Shared.AutoModeTiersEnabled);
 	}
 
 	/**
@@ -402,7 +400,7 @@ export class AutomodeService extends Disposable implements IAutomodeService {
 	 * pin below unreachable.
 	 */
 	private _resolveTier(chatRequest: IAutoModeRoutingRequest | undefined): AutoModeTier | undefined {
-		const override = this._configurationService.getConfig(ConfigKey.Advanced.AutoModeTierOverride);
+		const override = this._configurationService.getConfig(ConfigKey.Shared.AutoModeTierOverride);
 		if (override) {
 			const normalized = normalizeAutoModeTier(override);
 			// The override is internal, so unlike the picker it may select `fast`.

extensions/copilot/src/platform/endpoint/node/test/automodeService.spec.ts

@@ -17,7 +17,6 @@ import { createPngBytes } from '../../../image/common/test/testImageData';
 import { ILogService } from '../../../log/common/logService';
 import { IChatEndpoint } from '../../../networking/common/networking';
 import { NullRequestLogger } from '../../../requestLogger/node/nullRequestLogger';
-import { IExperimentationService, NullExperimentationService } from '../../../telemetry/common/nullExperimentationService';
 import { ITelemetryService } from '../../../telemetry/common/telemetry';
 import { defaultAutoModeTier } from '../../common/autoModeTiers';
 import { ICAPIClientService } from '../../common/capiClient';
@@ -37,7 +36,6 @@ describe('AutomodeService', () => {
 	let mockAuthService: IAuthenticationService;
 	let mockLogService: ILogService;
 	let mockInstantiationService: IInstantiationService;
-	let mockExpService: IExperimentationService;
 	let mockChatEndpoint: IChatEndpoint;
 	let configurationService: IConfigurationService;
 	let onDidAuthenticationChangeEmitter: Emitter<void>;
@@ -66,7 +64,6 @@ describe('AutomodeService', () => {
 			mockAuthService,
 			mockLogService,
 			mockInstantiationService,
-			mockExpService,
 			mockTelemetryService,
 			new NullRequestLogger(),
 			configurationService
@@ -79,11 +76,11 @@ describe('AutomodeService', () => {
 
 	/** Tiers are experiment-gated and off by default, so tier tests opt in. */
 	function enableTiers(): void {
-		configure(new Map<BaseConfig<unknown>, unknown>([[ConfigKey.Advanced.AutoModeTiersEnabled, true]]));
+		configure(new Map<BaseConfig<unknown>, unknown>([[ConfigKey.Shared.AutoModeTiersEnabled, true]]));
 	}
 
 	function setTierOverride(override: string): void {
-		configure(new Map<BaseConfig<unknown>, unknown>([[ConfigKey.Advanced.AutoModeTierOverride, override]]));
+		configure(new Map<BaseConfig<unknown>, unknown>([[ConfigKey.Shared.AutoModeTierOverride, override]]));
 	}
 
 	function makeAutoResponse(body: unknown, status = 200) {
@@ -158,7 +155,6 @@ describe('AutomodeService', () => {
 			)
 		} as unknown as IInstantiationService;
 
-		mockExpService = new NullExperimentationService();
 		configure();
 		mockTelemetryService = {
 			sendTelemetryEvent: vi.fn(),
@@ -733,8 +729,8 @@ describe('AutomodeService', () => {
 			mockAuto(autoResponse('gpt-4o'));
 
 			configure(new Map<BaseConfig<unknown>, unknown>([
-				[ConfigKey.Advanced.AutoModeTiersEnabled, true],
-				[ConfigKey.Advanced.AutoModeTierOverride, 'turbo'],
+				[ConfigKey.Shared.AutoModeTiersEnabled, true],
+				[ConfigKey.Shared.AutoModeTierOverride, 'turbo'],
 			]));
 			automodeService = createService();
 			await automodeService.resolveAutoModeEndpoint({
@@ -747,18 +743,24 @@ describe('AutomodeService', () => {
 			expect(autoRequestBodies()).toEqual([{ prompt: 'panel turn', tier: 'intelligence' }]);
 		});
 
-		it('announces tier support when the setting changes', async () => {
+		it('announces tier support from the effective setting, not a separate experiment lookup', async () => {
+			const getExperimentBasedConfig = vi.spyOn(configurationService, 'getExperimentBasedConfig');
 			automodeService = createService();
 			expect(automodeService.areAutoModeTiersSupported()).toBe(false);
 
 			let announced = 0;
 			const listener = automodeService.onDidChangeAutoModeTierSupport(() => announced++);
-			await configurationService.setConfig(ConfigKey.Advanced.AutoModeTiersEnabled, true);
+			await configurationService.setConfig(ConfigKey.Shared.AutoModeTiersEnabled, true);
 			// An unrelated change must not re-announce.
-			await configurationService.setConfig(ConfigKey.Advanced.AutoModeTierOverride, 'intelligence');
+			await configurationService.setConfig(ConfigKey.Shared.AutoModeTierOverride, 'intelligence');
+			await configurationService.setConfig(ConfigKey.Shared.AutoModeTiersEnabled, false);
 			listener.dispose();
 
-			expect({ announced, supported: automodeService.areAutoModeTiersSupported() }).toEqual({ announced: 1, supported: true });
+			expect({
+				announced,
+				supported: automodeService.areAutoModeTiersSupported(),
+				experimentLookups: getExperimentBasedConfig.mock.calls.length,
+			}).toEqual({ announced: 2, supported: false, experimentLookups: 0 });
 		});
 
 		it('does not reuse a cached endpoint from a different tier when /auto fails', async () => {

src/vs/platform/agentHost/common/autoModeTiers.ts

@@ -21,6 +21,16 @@ export function isAutoModeTier(value: unknown): value is AutoModeTier {
 	return autoModeTiers.some(tier => tier === value);
 }
 
+/** Maps retired picker and override values to the current runtime names, matching the Copilot extension. */
+export function normalizeAutoModeTier(value: unknown): unknown {
+	switch (value) {
+		case 'eco': return 'efficiency';
+		case 'balanced': return 'balance';
+		case 'max': return 'intelligence';
+		default: return value;
+	}
+}
+
 /**
  * Localized picker label for a routing profile, capitalizing an unrecognized value so a new profile
  * never surfaces raw. Wording matches the extension's `getAutoModeTierLabel`, which cannot be imported here.

src/vs/platform/agentHost/common/copilotCliConfig.ts

@@ -34,11 +34,10 @@ export const enum CopilotCliConfigKey {
 	ReasoningSummary = 'reasoningSummary',
 	/** Let the Auto router score prior turns instead of the latest message alone. Off by default. */
 	MultiTurnContextRouting = 'multiTurnContextRouting',
-	/**
-	 * Offer the Auto model's routing-profile ("Optimize for") picker. Off by default. Separate from
-	 * the extension's gate, which tracks CAPI readiness rather than the bundled runtime's support.
-	 */
+	/** Offer the Auto model's "Optimize for" picker. Shares the Copilot extension's setting and experiment. */
 	AutoModeTiers = 'autoModeTiers',
+	/** Override Auto's "Optimize for" preference, even when the picker is disabled. */
+	AutoModeTierOverride = 'autoModeTierOverride',
 	/** Tell the model to keep subagents on their default model unless the user asks otherwise. Off by default. */
 	SubagentModelGuidance = 'subagentModelGuidance',
 	/** Per-model capability overrides (family aliases) keyed by model id. */
@@ -47,10 +46,7 @@ export const enum CopilotCliConfigKey {
 
 export const CopilotCliVSCodeAssignmentContextKey = 'copilotCliVSCodeAssignmentContext';
 
-// VS Code `chat.agentHost.*` / `chat.copilot.*` setting IDs that feed the root-config
-// keys above, kept beside the keys they forward to. Registered in `chat.shared.contribution.ts`
-// and forwarded into the host's root config by `AgentHostCopilotCliSettingsContribution`
-// (and, for the terminal-tool toggle, `AgentHostTerminalContribution`).
+// Client setting IDs forwarded into the matching provider-owned root-config keys.
 
 export const AgentHostCustomTerminalToolEnabledSettingId = 'chat.agentHost.customTerminalTool.enabled';
 
@@ -71,12 +67,11 @@ export const AgentHostReasoningSummaryEnabledSettingId = 'chat.agentHost.copilot
 
 export const AgentHostMultiTurnContextRoutingEnabledSettingId = 'chat.agentHost.copilot.multiTurnContextRouting.enabled';
 
-export const AgentHostAutoModeTiersEnabledSettingId = 'chat.agentHost.copilot.autoModeTiers.enabled';
+export const CopilotAutoModeTiersEnabledSettingId = 'github.copilot.chat.autoMode.tiers.enabled';
 
-/**
- * ExP treatment gating the Auto routing-profile picker. The Copilot extension gates its own picker
- * on this same name, so one assignment turns tiers on for both harnesses.
- */
+export const CopilotAutoModeTierOverrideSettingId = 'github.copilot.chat.autoModeTierOverride';
+
+/** Applied to the shared setting's default by the workbench configuration service. */
 export const AutoModeTiersExperimentName = 'copilotchat.autoModeTiersEnabled';
 
 export const CopilotSubagentModelGuidanceEnabledSettingId = 'chat.copilot.subagentModelGuidance.enabled';
@@ -208,10 +203,16 @@ export const copilotCliConfigSchema = createSchema({
 	}),
 	[CopilotCliConfigKey.AutoModeTiers]: schemaProperty<boolean>({
 		type: 'boolean',
-		title: localize('agentHost.config.autoModeTiers.title', "Auto Routing Profiles"),
-		description: localize('agentHost.config.autoModeTiers.description', "When enabled, the Auto model offers an \"Optimize for\" picker that biases routing toward efficiency, balance, or intelligence. The profile is chosen before a session starts and applies for its lifetime."),
+		title: localize('agentHost.config.autoModeTiers.title', "Auto Optimize for"),
+		description: localize('agentHost.config.autoModeTiers.description', "When enabled, the Auto model offers an \"Optimize for\" picker with Efficiency, Balance, and Intelligence options. You can change the preference during a session. When disabled, the service chooses how to route unless an override is configured."),
 		default: false,
 	}),
+	[CopilotCliConfigKey.AutoModeTierOverride]: schemaProperty<string>({
+		type: 'string',
+		title: localize('agentHost.config.autoModeTierOverride.title', "Auto Optimize for Override"),
+		description: localize('agentHost.config.autoModeTierOverride.description', "Overrides Auto's \"Optimize for\" preference, even when the picker is disabled. Accepts efficiency, balance, or intelligence. Applied when a session is created or resumed and when its model changes. Empty or unsupported values use the picker or service defaults."),
+		default: '',
+	}),
 	[CopilotCliConfigKey.SubagentModelGuidance]: schemaProperty<boolean>({
 		type: 'boolean',
 		title: localize('agentHost.config.subagentModelGuidance.title', "Subagent Model Guidance"),