feat: configurable time, weekday, and timezone in date context

package.json

@@ -4271,6 +4271,43 @@
 							"experimental"
 						]
 					},
+					"github.copilot.chat.advanced.context.timeFormat": {
+						"type": "string",
+						"default": "off",
+						"enum": [
+							"off",
+							"24h",
+							"12h"
+						],
+						"enumDescriptions": [
+							"Do not include current time",
+							"24-hour format (e.g., 23:06:32)",
+							"12-hour format (e.g., 11:06:32 PM)"
+						],
+						"markdownDescription": "%github.copilot.config.advanced.context.timeFormat%",
+						"tags": [
+							"advanced",
+							"experimental"
+						]
+					},
+					"github.copilot.chat.advanced.context.showWeekday": {
+						"type": "boolean",
+						"default": false,
+						"markdownDescription": "%github.copilot.config.advanced.context.showWeekday%",
+						"tags": [
+							"advanced",
+							"experimental"
+						]
+					},
+					"github.copilot.chat.advanced.context.showTimezone": {
+						"type": "boolean",
+						"default": false,
+						"markdownDescription": "%github.copilot.config.advanced.context.showTimezone%",
+						"tags": [
+							"advanced",
+							"experimental"
+						]
+					},
 					"github.copilot.chat.agent.omitFileAttachmentContents": {
 						"type": "boolean",
 						"default": false,

package.nls.json

@@ -383,6 +383,9 @@
 	"github.copilot.config.inlineEdits.chatSessionContextProvider.enabled": "Enable chat session context provider for next edit suggestions.",
 	"github.copilot.config.codesearch.agent.enabled": "Enable code search capabilities in agent mode.",
 	"github.copilot.config.agent.temperature": "Temperature setting for agent mode requests.",
+	"github.copilot.config.advanced.context.timeFormat": "Include the current time in the date context provided to the model. Choose between 24-hour and 12-hour format, or disable.",
+	"github.copilot.config.advanced.context.showWeekday": "Include the day of the week in the date context provided to the model.",
+	"github.copilot.config.advanced.context.showTimezone": "Include the timezone offset (e.g., GMT+2) in the date context provided to the model. Only applies when `#github.copilot.chat.advanced.context.timeFormat#` is not \"off\".",
 	"github.copilot.config.agent.omitFileAttachmentContents": "Omit summarized file contents from file attachments in agent mode, to encourage the agent to properly read and explore.",
 	"github.copilot.config.agent.largeToolResultsToDisk.enabled": "When enabled, large tool results are written to disk instead of being included directly in the context, helping manage context window usage.",
 	"github.copilot.config.agent.largeToolResultsToDisk.thresholdBytes": "The size threshold in bytes above which tool results are written to disk. Only applies when largeToolResultsToDisk.enabled is true.",

src/extension/prompts/common/currentDateContext.ts

@@ -0,0 +1,49 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { ConfigKey, IConfigurationService } from '../../../platform/configuration/common/configurationService';
+
+/**
+ * Formats the current date/time context string for inclusion in prompts.
+ * Respects user settings for time, weekday, and timezone display.
+ *
+ * Default (all settings off): "The current date is May 3, 2026."
+ * With all settings on: "The current date is Sunday, May 3, 2026. The current time is 23:06:32 GMT+2."
+ * Timezone is always in GMT±N offset format for consistency across all regions.
+ *
+ * timeFormat values: "off" (default), "24h", "12h"
+ */
+export function formatCurrentDateContext(configurationService: IConfigurationService): string {
+	const now = new Date();
+	const parts: string[] = [];
+
+	parts.push('The current date is ');
+
+	if (configurationService.getConfig(ConfigKey.Advanced.ShowWeekday)) {
+		parts.push(now.toLocaleDateString('en-US', { weekday: 'long' }));
+		parts.push(', ');
+	}
+
+	parts.push(now.toLocaleDateString('en-US', { year: 'numeric', month: 'long', day: 'numeric' }));
+	parts.push('.');
+
+	const timeFormat = configurationService.getConfig(ConfigKey.Advanced.TimeFormat);
+	if (timeFormat && timeFormat !== 'off') {
+		const hour12 = timeFormat === '12h';
+		const timeStr = now.toLocaleTimeString('en-US', { hour: '2-digit', minute: '2-digit', second: '2-digit', hour12 });
+		parts.push(` The current time is ${timeStr}`);
+
+		if (configurationService.getConfig(ConfigKey.Advanced.ShowTimezone)) {
+			const tz = new Intl.DateTimeFormat('en-US', { timeZoneName: 'shortOffset' }).formatToParts(now).find(p => p.type === 'timeZoneName')?.value;
+			if (tz) {
+				parts.push(` ${tz}`);
+			}
+		}
+
+		parts.push('.');
+	}
+
+	return parts.join('');
+}

src/extension/prompts/common/test/currentDateContext.spec.ts

@@ -0,0 +1,181 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { formatCurrentDateContext } from '../currentDateContext';
+import { ConfigKey, IConfigurationService } from '../../../../platform/configuration/common/configurationService';
+
+function createMockConfigService(overrides: { timeFormat?: string; showWeekday?: boolean; showTimezone?: boolean } = {}): IConfigurationService {
+	return {
+		_serviceBrand: undefined,
+		getConfig(key: unknown) {
+			if (key === ConfigKey.Advanced.TimeFormat) { return overrides.timeFormat ?? 'off'; }
+			if (key === ConfigKey.Advanced.ShowWeekday) { return overrides.showWeekday ?? false; }
+			if (key === ConfigKey.Advanced.ShowTimezone) { return overrides.showTimezone ?? false; }
+			return undefined;
+		},
+	} as unknown as IConfigurationService;
+}
+
+describe('formatCurrentDateContext', () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+		vi.stubEnv('TZ', 'UTC');
+		// Monday, June 15, 2026 14:30:45 UTC
+		vi.setSystemTime(new Date('2026-06-15T14:30:45.000Z'));
+	});
+
+	afterEach(() => {
+		vi.useRealTimers();
+		vi.unstubAllEnvs();
+	});
+
+	it('returns date only by default (all settings off)', () => {
+		const result = formatCurrentDateContext(createMockConfigService());
+		expect(result).toBe('The current date is June 15, 2026.');
+	});
+
+	it('includes time in 24h format', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '24h' }));
+		expect(result).toBe('The current date is June 15, 2026. The current time is 14:30:45.');
+	});
+
+	it('includes time in 12h format', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '12h' }));
+		expect(result).toBe('The current date is June 15, 2026. The current time is 02:30:45 PM.');
+	});
+
+	it('includes weekday when showWeekday is enabled', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ showWeekday: true }));
+		expect(result).toBe('The current date is Monday, June 15, 2026.');
+	});
+
+	it('includes timezone when both time and showTimezone are enabled', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '24h', showTimezone: true }));
+		expect(result).toBe('The current date is June 15, 2026. The current time is 14:30:45 GMT+0.');
+	});
+
+	it('does not include timezone when time is off', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ showTimezone: true }));
+		expect(result).toBe('The current date is June 15, 2026.');
+	});
+
+	it('includes all parts when all settings are enabled (24h)', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '24h', showWeekday: true, showTimezone: true }));
+		expect(result).toBe('The current date is Monday, June 15, 2026. The current time is 14:30:45 GMT+0.');
+	});
+
+	it('includes all parts when all settings are enabled (12h)', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '12h', showWeekday: true, showTimezone: true }));
+		expect(result).toBe('The current date is Monday, June 15, 2026. The current time is 02:30:45 PM GMT+0.');
+	});
+
+	it('weekday + time without timezone', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '24h', showWeekday: true }));
+		expect(result).toBe('The current date is Monday, June 15, 2026. The current time is 14:30:45.');
+	});
+
+	it('treats unknown timeFormat values as 24h', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: 'garbage' as any }));
+		expect(result).toBe('The current date is June 15, 2026. The current time is 14:30:45.');
+	});
+});
+
+describe('formatCurrentDateContext (US Eastern timezone)', () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+		vi.stubEnv('TZ', 'America/New_York');
+		vi.setSystemTime(new Date('2026-06-15T14:30:45.000Z'));
+	});
+
+	afterEach(() => {
+		vi.useRealTimers();
+		vi.unstubAllEnvs();
+	});
+
+	it('shows local time and GMT-4 timezone', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '24h', showTimezone: true }));
+		expect(result).toBe('The current date is June 15, 2026. The current time is 10:30:45 GMT-4.');
+	});
+
+	it('shows all parts in Eastern timezone', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '12h', showWeekday: true, showTimezone: true }));
+		expect(result).toBe('The current date is Monday, June 15, 2026. The current time is 10:30:45 AM GMT-4.');
+	});
+});
+
+describe('formatCurrentDateContext (Tokyo timezone)', () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+		vi.stubEnv('TZ', 'Asia/Tokyo');
+		vi.setSystemTime(new Date('2026-06-15T14:30:45.000Z'));
+	});
+
+	afterEach(() => {
+		vi.useRealTimers();
+		vi.unstubAllEnvs();
+	});
+
+	it('shows local time in Tokyo timezone', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '24h', showTimezone: true }));
+		expect(result).toBe('The current date is June 15, 2026. The current time is 23:30:45 GMT+9.');
+	});
+});
+
+describe('formatCurrentDateContext (US Pacific winter — PST)', () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+		vi.stubEnv('TZ', 'America/Los_Angeles');
+		// January = PST (no daylight saving)
+		vi.setSystemTime(new Date('2026-01-15T20:30:45.000Z'));
+	});
+
+	afterEach(() => {
+		vi.useRealTimers();
+		vi.unstubAllEnvs();
+	});
+
+	it('shows GMT-8 in LA winter', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '24h', showTimezone: true }));
+		expect(result).toBe('The current date is January 15, 2026. The current time is 12:30:45 GMT-8.');
+	});
+});
+
+describe('formatCurrentDateContext (India — non-whole-hour offset)', () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+		vi.stubEnv('TZ', 'Asia/Kolkata');
+		vi.setSystemTime(new Date('2026-06-15T14:30:45.000Z'));
+	});
+
+	afterEach(() => {
+		vi.useRealTimers();
+		vi.unstubAllEnvs();
+	});
+
+	it('shows GMT+5:30 offset', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '24h', showTimezone: true }));
+		expect(result).toBe('The current date is June 15, 2026. The current time is 20:00:45 GMT+5:30.');
+	});
+});
+
+describe('formatCurrentDateContext (date rollover — UTC night → Tokyo next day)', () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+		vi.stubEnv('TZ', 'Asia/Tokyo');
+		// UTC Sunday 23:30 → Tokyo Monday 08:30, date rolls to June 16
+		vi.setSystemTime(new Date('2026-06-15T23:30:45.000Z'));
+	});
+
+	afterEach(() => {
+		vi.useRealTimers();
+		vi.unstubAllEnvs();
+	});
+
+	it('shows correct local date and weekday after rollover', () => {
+		const result = formatCurrentDateContext(createMockConfigService({ timeFormat: '24h', showWeekday: true, showTimezone: true }));
+		expect(result).toBe('The current date is Tuesday, June 16, 2026. The current time is 08:30:45 GMT+9.');
+	});
+});

src/extension/prompts/node/agent/agentPrompt.tsx

@@ -8,6 +8,7 @@ import type { ChatRequestEditedFileEvent, LanguageModelToolInformation, Notebook
 import { sessionResourceToId } from '../../../../platform/chat/common/chatDebugFileLoggerService';
 import { ChatLocation } from '../../../../platform/chat/common/commonTypes';
 import { ConfigKey, IConfigurationService } from '../../../../platform/configuration/common/configurationService';
+import { formatCurrentDateContext } from '../../common/currentDateContext';
 import { ICustomInstructionsService } from '../../../../platform/customInstructions/common/customInstructionsService';
 import { USE_SKILL_ADHERENCE_PROMPT_SETTING } from '../../../../platform/customInstructions/common/promptTypes';
 import { CacheType } from '../../../../platform/endpoint/common/endpointTypes';
@@ -492,15 +493,15 @@ class UserOSPrompt extends PromptElement<BasePromptElementProps> {
 class CurrentDatePrompt extends PromptElement<BasePromptElementProps> {
 	constructor(
 		props: BasePromptElementProps,
-		@IEnvService private readonly envService: IEnvService) {
+		@IEnvService private readonly envService: IEnvService,
+		@IConfigurationService private readonly configurationService: IConfigurationService) {
 		super(props);
 	}
 
 	async render(state: void, sizing: PromptSizing) {
-		const dateStr = new Date().toLocaleDateString(undefined, { year: 'numeric', month: 'long', day: 'numeric' });
 		// Only include current date when not running simulations, since if we generate cache entries with the current date, the cache will be invalidated every day
 		return (
-			!this.envService.isSimulation() && <>The current date is {dateStr}.</>
+			!this.envService.isSimulation() && <>{formatCurrentDateContext(this.configurationService)}</>
 		);
 	}
 }

src/platform/configuration/common/configurationService.ts

@@ -604,6 +604,9 @@ export namespace ConfigKey {
 		export const EditRecordingEnabled = defineAndMigrateSetting('chat.advanced.editRecording.enabled', 'chat.editRecording.enabled', false);
 		export const CodeSearchAgentEnabled = defineAndMigrateSetting<boolean | undefined>('chat.advanced.codesearch.agent.enabled', 'chat.codesearch.agent.enabled', true);
 		export const AgentTemperature = defineAndMigrateSetting<number | undefined>('chat.advanced.agent.temperature', 'chat.agent.temperature', undefined);
+		export const TimeFormat = defineSetting<'off' | '24h' | '12h'>('chat.advanced.context.timeFormat', ConfigType.Simple, 'off');
+		export const ShowWeekday = defineSetting<boolean>('chat.advanced.context.showWeekday', ConfigType.Simple, false);
+		export const ShowTimezone = defineSetting<boolean>('chat.advanced.context.showTimezone', ConfigType.Simple, false);
 		export const EnableUserPreferences = defineAndMigrateSetting<boolean>('chat.advanced.enableUserPreferences', 'chat.enableUserPreferences', false);
 		export const SummarizeAgentConversationHistoryThreshold = defineAndMigrateSetting<number | undefined>('chat.advanced.summarizeAgentConversationHistoryThreshold', 'chat.summarizeAgentConversationHistoryThreshold', undefined);
 		export const AgentHistorySummarizationMode = defineAndMigrateSetting<string | undefined>('chat.advanced.agentHistorySummarizationMode', 'chat.agentHistorySummarizationMode', undefined);