diff --git a/Extension/src/LanguageServer/client.ts b/Extension/src/LanguageServer/client.ts
index e46743815e..c05034e643 100644
--- a/Extension/src/LanguageServer/client.ts
+++ b/Extension/src/LanguageServer/client.ts
@@ -541,6 +541,19 @@ export interface ChatContextResult {
     targetArchitecture: string;
 }
 
+export interface FileContextResult {
+    compilerArguments: string[];
+}
+
+export interface ProjectContextResult {
+    language: string;
+    standardVersion: string;
+    compiler: string;
+    targetPlatform: string;
+    targetArchitecture: string;
+    fileContext: FileContextResult;
+}
+
 // Requests
 const PreInitializationRequest: RequestType<void, string, void> = new RequestType<void, string, void>('cpptools/preinitialize');
 const InitializationRequest: RequestType<CppInitializationParams, void, void> = new RequestType<CppInitializationParams, void, void>('cpptools/initialize');
@@ -561,6 +574,7 @@ const GenerateDoxygenCommentRequest: RequestType<GenerateDoxygenCommentParams, G
 const ChangeCppPropertiesRequest: RequestType<CppPropertiesParams, void, void> = new RequestType<CppPropertiesParams, void, void>('cpptools/didChangeCppProperties');
 const IncludesRequest: RequestType<GetIncludesParams, GetIncludesResult, void> = new RequestType<GetIncludesParams, GetIncludesResult, void>('cpptools/getIncludes');
 const CppContextRequest: RequestType<void, ChatContextResult, void> = new RequestType<void, ChatContextResult, void>('cpptools/getChatContext');
+const ProjectContextRequest: RequestType<void, ProjectContextResult, void> = new RequestType<void, ProjectContextResult, void>('cpptools/getProjectContext');
 
 // Notifications to the server
 const DidOpenNotification: NotificationType<DidOpenTextDocumentParams> = new NotificationType<DidOpenTextDocumentParams>('textDocument/didOpen');
@@ -792,6 +806,7 @@ export interface Client {
     addTrustedCompiler(path: string): Promise<void>;
     getIncludes(maxDepth: number, token: vscode.CancellationToken): Promise<GetIncludesResult>;
     getChatContext(token: vscode.CancellationToken): Promise<ChatContextResult>;
+    getProjectContext(token: vscode.CancellationToken): Promise<ProjectContextResult>;
 }
 
 export function createClient(workspaceFolder?: vscode.WorkspaceFolder): Client {
@@ -2220,6 +2235,12 @@ export class DefaultClient implements Client {
             () => this.languageClient.sendRequest(CppContextRequest, null, token), token);
     }
 
+    public async getProjectContext(token: vscode.CancellationToken): Promise<ProjectContextResult> {
+        await withCancellation(this.ready, token);
+        return DefaultClient.withLspCancellationHandling(
+            () => this.languageClient.sendRequest(ProjectContextRequest, null, token), token);
+    }
+
     /**
      * a Promise that can be awaited to know when it's ok to proceed.
      *
@@ -4123,4 +4144,5 @@ class NullClient implements Client {
     addTrustedCompiler(path: string): Promise<void> { return Promise.resolve(); }
     getIncludes(maxDepth: number, token: vscode.CancellationToken): Promise<GetIncludesResult> { return Promise.resolve({} as GetIncludesResult); }
     getChatContext(token: vscode.CancellationToken): Promise<ChatContextResult> { return Promise.resolve({} as ChatContextResult); }
+    getProjectContext(token: vscode.CancellationToken): Promise<ProjectContextResult> { return Promise.resolve({} as ProjectContextResult); }
 }
diff --git a/Extension/src/LanguageServer/copilotProviders.ts b/Extension/src/LanguageServer/copilotProviders.ts
index f23554f76d..a1340669ad 100644
--- a/Extension/src/LanguageServer/copilotProviders.ts
+++ b/Extension/src/LanguageServer/copilotProviders.ts
@@ -6,8 +6,9 @@
 
 import * as vscode from 'vscode';
 import * as util from '../common';
-import { ChatContextResult, GetIncludesResult } from './client';
+import { GetIncludesResult } from './client';
 import { getActiveClient } from './extension';
+import { getProjectContext } from './lmTool';
 
 export interface CopilotTrait {
     name: string;
@@ -38,19 +39,51 @@ export async function registerRelatedFilesProvider(): Promise<void> {
 
                         const getIncludesHandler = async () => (await getIncludesWithCancellation(1, token))?.includedFiles.map(file => vscode.Uri.file(file)) ?? [];
                         const getTraitsHandler = async () => {
-                            const chatContext: ChatContextResult | undefined = await (getActiveClient().getChatContext(token) ?? undefined);
+                            const cppContext = await getProjectContext(context, token);
 
-                            if (!chatContext) {
+                            if (!cppContext) {
                                 return undefined;
                             }
 
                             let traits: CopilotTrait[] = [
-                                { name: "language", value: chatContext.language, includeInPrompt: true, promptTextOverride: `The language is ${chatContext.language}.` },
-                                { name: "compiler", value: chatContext.compiler, includeInPrompt: true, promptTextOverride: `This project compiles using ${chatContext.compiler}.` },
-                                { name: "standardVersion", value: chatContext.standardVersion, includeInPrompt: true, promptTextOverride: `This project uses the ${chatContext.standardVersion} language standard.` },
-                                { name: "targetPlatform", value: chatContext.targetPlatform, includeInPrompt: true, promptTextOverride: `This build targets ${chatContext.targetPlatform}.` },
-                                { name: "targetArchitecture", value: chatContext.targetArchitecture, includeInPrompt: true, promptTextOverride: `This build targets ${chatContext.targetArchitecture}.` }
+                                { name: "intellisense", value: 'intellisense', includeInPrompt: true, promptTextOverride: `IntelliSense is currently configured with the following compiler information. It reflects the active configuration, and the project may have more configurations targeting different platforms.` },
+                                { name: "intellisenseBegin", value: 'Begin', includeInPrompt: true, promptTextOverride: `Beginning of IntelliSense information.` }
                             ];
+                            if (cppContext.language) {
+                                traits.push({ name: "language", value: cppContext.language, includeInPrompt: true, promptTextOverride: `The language is ${cppContext.language}.` });
+                            }
+                            if (cppContext.compiler) {
+                                traits.push({ name: "compiler", value: cppContext.compiler, includeInPrompt: true, promptTextOverride: `This project compiles using ${cppContext.compiler}.` });
+                            }
+                            if (cppContext.standardVersion) {
+                                traits.push({ name: "standardVersion", value: cppContext.standardVersion, includeInPrompt: true, promptTextOverride: `This project uses the ${cppContext.standardVersion} language standard.` });
+                            }
+                            if (cppContext.targetPlatform) {
+                                traits.push({ name: "targetPlatform", value: cppContext.targetPlatform, includeInPrompt: true, promptTextOverride: `This build targets ${cppContext.targetPlatform}.` });
+                            }
+                            if (cppContext.targetArchitecture) {
+                                traits.push({ name: "targetArchitecture", value: cppContext.targetArchitecture, includeInPrompt: true, promptTextOverride: `This build targets ${cppContext.targetArchitecture}.` });
+                            }
+                            let directAsks: string = '';
+                            if (cppContext.compilerArguments.length > 0) {
+                                // Example: JSON.stringify({'-fno-rtti': "Do not generate code using RTTI keywords."})
+                                const directAskMap: { [key: string]: string } = JSON.parse(context.flags.copilotcppCompilerArgumentDirectAskMap as string ?? '{}');
+                                const updatedArguments = cppContext.compilerArguments.filter(arg => {
+                                    if (directAskMap[arg]) {
+                                        directAsks += `${directAskMap[arg]} `;
+                                        return false;
+                                    }
+                                    return true;
+                                });
+
+                                const compilerArgumentsValue = updatedArguments.join(", ");
+                                traits.push({ name: "compilerArguments", value: compilerArgumentsValue, includeInPrompt: true, promptTextOverride: `The compiler arguments include: ${compilerArgumentsValue}.` });
+                            }
+                            if (directAsks) {
+                                traits.push({ name: "directAsks", value: directAsks, includeInPrompt: true, promptTextOverride: directAsks });
+                            }
+
+                            traits.push({ name: "intellisenseEnd", value: 'End', includeInPrompt: true, promptTextOverride: `End of IntelliSense information.` });
 
                             const excludeTraits = context.flags.copilotcppExcludeTraits as string[] ?? [];
                             traits = traits.filter(trait => !excludeTraits.includes(trait.name));
diff --git a/Extension/src/LanguageServer/lmTool.ts b/Extension/src/LanguageServer/lmTool.ts
index c3fad8b6eb..82c54d3135 100644
--- a/Extension/src/LanguageServer/lmTool.ts
+++ b/Extension/src/LanguageServer/lmTool.ts
@@ -9,9 +9,13 @@ import { localize } from 'vscode-nls';
 import * as util from '../common';
 import * as logger from '../logger';
 import * as telemetry from '../telemetry';
-import { ChatContextResult } from './client';
+import { ChatContextResult, ProjectContextResult } from './client';
 import { getClients } from './extension';
+import { checkTime } from './utils';
 
+const MSVC: string = 'MSVC';
+const Clang: string = 'Clang';
+const GCC: string = 'GCC';
 const knownValues: { [Property in keyof ChatContextResult]?: { [id: string]: string } } = {
     language: {
         'c': 'C',
@@ -19,9 +23,9 @@ const knownValues: { [Property in keyof ChatContextResult]?: { [id: string]: str
         'cuda-cpp': 'CUDA C++'
     },
     compiler: {
-        'msvc': 'MSVC',
-        'clang': 'Clang',
-        'gcc': 'GCC'
+        'msvc': MSVC,
+        'clang': Clang,
+        'gcc': GCC
     },
     standardVersion: {
         'c++98': 'C++98',
@@ -44,6 +48,112 @@ const knownValues: { [Property in keyof ChatContextResult]?: { [id: string]: str
     }
 };
 
+function formatChatContext(context: ChatContextResult | ProjectContextResult): void {
+    type KnownKeys = 'language' | 'standardVersion' | 'compiler' | 'targetPlatform';
+    for (const key in knownValues) {
+        const knownKey = key as KnownKeys;
+        if (knownValues[knownKey] && context[knownKey]) {
+            // Clear the value if it's not in the known values.
+            context[knownKey] = knownValues[knownKey][context[knownKey]] || "";
+        }
+    }
+}
+
+export interface ProjectContext {
+    language: string;
+    standardVersion: string;
+    compiler: string;
+    targetPlatform: string;
+    targetArchitecture: string;
+    compilerArguments: string[];
+}
+
+// Set these values for local testing purpose without involving control tower.
+const defaultCompilerArgumentFilters: { [id: string]: RegExp | undefined } = {
+    MSVC: undefined, // Example: /^(\/std:.*|\/EHs-c-|\/GR-|\/await.*)$/,
+    Clang: undefined,
+    GCC: undefined // Example: /^(-std=.*|-fno-rtti|-fno-exceptions)$/
+};
+
+function filterComplierArguments(compiler: string, compilerArguments: string[], context: { flags: Record<string, unknown> }): string[] {
+    const defaultFilter: RegExp | undefined = defaultCompilerArgumentFilters[compiler] ?? undefined;
+    let additionalFilter: RegExp | undefined;
+    switch (compiler) {
+        case MSVC:
+            additionalFilter = context.flags.copilotcppMsvcCompilerArgumentFilter ? new RegExp(context.flags.copilotcppMsvcCompilerArgumentFilter as string) : undefined;
+            break;
+        case Clang:
+            additionalFilter = context.flags.copilotcppClangCompilerArgumentFilter ? new RegExp(context.flags.copilotcppClangCompilerArgumentFilter as string) : undefined;
+            break;
+        case GCC:
+            additionalFilter = context.flags.copilotcppGccCompilerArgumentFilter ? new RegExp(context.flags.copilotcppGccCompilerArgumentFilter as string) : undefined;
+            break;
+    }
+
+    return compilerArguments.filter(arg => defaultFilter?.test(arg) || additionalFilter?.test(arg));
+}
+
+export async function getProjectContext(context: { flags: Record<string, unknown> }, token: vscode.CancellationToken): Promise<ProjectContext | undefined> {
+    const telemetryProperties: Record<string, string> = {};
+    try {
+        const projectContext = await checkTime<ProjectContextResult | undefined>(async () => await getClients()?.ActiveClient?.getProjectContext(token) ?? undefined);
+        telemetryProperties["time"] = projectContext.time.toString();
+        if (!projectContext.result) {
+            return undefined;
+        }
+
+        formatChatContext(projectContext.result);
+
+        const result: ProjectContext = {
+            language: projectContext.result.language,
+            standardVersion: projectContext.result.standardVersion,
+            compiler: projectContext.result.compiler,
+            targetPlatform: projectContext.result.targetPlatform,
+            targetArchitecture: projectContext.result.targetArchitecture,
+            compilerArguments: []
+        };
+
+        if (projectContext.result.language) {
+            telemetryProperties["language"] = projectContext.result.language;
+        }
+        if (projectContext.result.compiler) {
+            telemetryProperties["compiler"] = projectContext.result.compiler;
+        }
+        if (projectContext.result.standardVersion) {
+            telemetryProperties["standardVersion"] = projectContext.result.standardVersion;
+        }
+        if (projectContext.result.targetPlatform) {
+            telemetryProperties["targetPlatform"] = projectContext.result.targetPlatform;
+        }
+        if (projectContext.result.targetArchitecture) {
+            telemetryProperties["targetArchitecture"] = projectContext.result.targetArchitecture;
+        }
+        telemetryProperties["compilerArgumentCount"] = projectContext.result.fileContext.compilerArguments.length.toString();
+        // Telemtry to learn about the argument distribution. The filtered arguments are expected to be non-PII.
+        if (projectContext.result.fileContext.compilerArguments.length) {
+            const filteredCompilerArguments = filterComplierArguments(projectContext.result.compiler, projectContext.result.fileContext.compilerArguments, context);
+            if (filteredCompilerArguments.length > 0) {
+                telemetryProperties["filteredCompilerArguments"] = filteredCompilerArguments.join(', ');
+                result.compilerArguments = filteredCompilerArguments;
+            }
+        }
+
+        return result;
+    }
+    catch {
+        try {
+            logger.getOutputChannelLogger().appendLine(localize("copilot.cppcontext.error", "Error while retrieving the project context."));
+        }
+        catch {
+            // Intentionally swallow any exception.
+        }
+        telemetryProperties["error"] = "true";
+        return undefined;
+    } finally {
+        telemetry.logLanguageModelToolEvent('Completions/tool', telemetryProperties);
+    }
+}
+
 export class CppConfigurationLanguageModelTool implements vscode.LanguageModelTool<void> {
     public async invoke(options: vscode.LanguageModelToolInvocationOptions<void>, token: vscode.CancellationToken): Promise<vscode.LanguageModelToolResult> {
         return new vscode.LanguageModelToolResult([
@@ -63,13 +173,7 @@ export class CppConfigurationLanguageModelTool implements vscode.LanguageModelTo
                 return 'No configuration information is available for the active document.';
             }
 
-            for (const key in knownValues) {
-                const knownKey = key as keyof ChatContextResult;
-                if (knownValues[knownKey] && chatContext[knownKey]) {
-                    // Clear the value if it's not in the known values.
-                    chatContext[knownKey] = knownValues[knownKey][chatContext[knownKey]] || "";
-                }
-            }
+            formatChatContext(chatContext);
 
             let contextString = "";
             if (chatContext.language) {
@@ -100,7 +204,7 @@ export class CppConfigurationLanguageModelTool implements vscode.LanguageModelTo
             telemetryProperties["error"] = "true";
             return "";
         } finally {
-            telemetry.logLanguageModelToolEvent('cpp', telemetryProperties);
+            telemetry.logLanguageModelToolEvent('Chat/Tool/cpp', telemetryProperties);
         }
     }
 
diff --git a/Extension/src/LanguageServer/utils.ts b/Extension/src/LanguageServer/utils.ts
index e8c8073ee1..1ad736dad5 100644
--- a/Extension/src/LanguageServer/utils.ts
+++ b/Extension/src/LanguageServer/utils.ts
@@ -112,3 +112,9 @@ export async function withCancellation<T>(promise: Promise<T>, token: vscode.Can
         });
     });
 }
+
+export async function checkTime<T>(fn: () => Promise<T>): Promise<{ result: T; time: number }> {
+    const start = Date.now();
+    const result = await fn();
+    return { result, time: Date.now() - start };
+}
diff --git a/Extension/src/telemetry.ts b/Extension/src/telemetry.ts
index 600ffa4c45..434a222854 100644
--- a/Extension/src/telemetry.ts
+++ b/Extension/src/telemetry.ts
@@ -126,7 +126,7 @@ export function logLanguageServerEvent(eventName: string, properties?: Record<st
 export function logLanguageModelToolEvent(eventName: string, properties?: Record<string, string>, metrics?: Record<string, number>): void {
     const sendTelemetry = () => {
         if (experimentationTelemetry) {
-            const eventNamePrefix: string = "C_Cpp/Copilot/Chat/Tool/";
+            const eventNamePrefix: string = "C_Cpp/Copilot/";
             experimentationTelemetry.sendTelemetryEvent(eventNamePrefix + eventName, properties, metrics);
         }
     };
diff --git a/Extension/test/scenarios/SingleRootProject/tests/copilotProviders.test.ts b/Extension/test/scenarios/SingleRootProject/tests/copilotProviders.test.ts
index 54052e122d..89c74ce954 100644
--- a/Extension/test/scenarios/SingleRootProject/tests/copilotProviders.test.ts
+++ b/Extension/test/scenarios/SingleRootProject/tests/copilotProviders.test.ts
@@ -9,11 +9,13 @@ import * as proxyquire from 'proxyquire';
 import * as sinon from 'sinon';
 import * as vscode from 'vscode';
 import * as util from '../../../../src/common';
-import { ChatContextResult, DefaultClient, GetIncludesResult } from '../../../../src/LanguageServer/client';
+import { DefaultClient, GetIncludesResult } from '../../../../src/LanguageServer/client';
 import { CopilotApi, CopilotTrait } from '../../../../src/LanguageServer/copilotProviders';
 import * as extension from '../../../../src/LanguageServer/extension';
+import * as lmTool from '../../../../src/LanguageServer/lmTool';
+import { ProjectContext } from '../../../../src/LanguageServer/lmTool';
 
-describe('registerRelatedFilesProvider', () => {
+describe('copilotProviders Tests', () => {
     let moduleUnderTest: any;
     let mockCopilotApi: sinon.SinonStubbedInstance<CopilotApi>;
     let getActiveClientStub: sinon.SinonStub;
@@ -74,12 +76,12 @@ describe('registerRelatedFilesProvider', () => {
         sinon.restore();
     });
 
-    const arrange = ({ vscodeExtension, getIncludeFiles, chatContext, rootUri, flags }:
-    { vscodeExtension?: vscode.Extension<unknown>; getIncludeFiles?: GetIncludesResult; chatContext?: ChatContextResult; rootUri?: vscode.Uri; flags?: Record<string, unknown> } =
-    { vscodeExtension: undefined, getIncludeFiles: undefined, chatContext: undefined, rootUri: undefined, flags: {} }
+    const arrange = ({ vscodeExtension, getIncludeFiles, projectContext, rootUri, flags }:
+    { vscodeExtension?: vscode.Extension<unknown>; getIncludeFiles?: GetIncludesResult; projectContext?: ProjectContext; rootUri?: vscode.Uri; flags?: Record<string, unknown> } =
+    { vscodeExtension: undefined, getIncludeFiles: undefined, projectContext: undefined, rootUri: undefined, flags: {} }
     ) => {
         activeClientStub.getIncludes.resolves(getIncludeFiles);
-        activeClientStub.getChatContext.resolves(chatContext);
+        sinon.stub(lmTool, 'getProjectContext').resolves(projectContext);
         sinon.stub(activeClientStub, 'RootUri').get(() => rootUri);
         mockCopilotApi.registerRelatedFilesProvider.callsFake((_providerId: { extensionId: string; languageId: string }, callback: (uri: vscode.Uri, context: { flags: Record<string, unknown> }, cancellationToken: vscode.CancellationToken) => Promise<{ entries: vscode.Uri[]; traits?: CopilotTrait[] }>) => {
             const tokenSource = new vscode.CancellationTokenSource();
@@ -108,11 +110,11 @@ describe('registerRelatedFilesProvider', () => {
         ok(mockCopilotApi.registerRelatedFilesProvider.calledWithMatch(sinon.match({ extensionId: 'test-extension-id', languageId: sinon.match.in(['c', 'cpp', 'cuda-cpp']) })), 'registerRelatedFilesProvider should be called with the correct providerId and languageId');
     });
 
-    it('should not add #cpp traits when ChatContext isn\'t available.', async () => {
+    it('should not provide project context traits when ChatContext isn\'t available.', async () => {
         arrange({
             vscodeExtension: vscodeExtension,
             getIncludeFiles: { includedFiles },
-            chatContext: undefined,
+            projectContext: undefined,
             rootUri,
             flags: { copilotcppTraits: true }
         });
@@ -130,17 +132,20 @@ describe('registerRelatedFilesProvider', () => {
         ok(result.traits === undefined, 'result.traits should be undefined');
     });
 
-    it('should not add #cpp traits when copilotcppTraits flag is false.', async () => {
+    const projectContextNoArgs: ProjectContext = {
+        language: 'C++',
+        standardVersion: 'C++20',
+        compiler: 'MSVC',
+        targetPlatform: 'Windows',
+        targetArchitecture: 'x64',
+        compilerArguments: []
+    };
+
+    it('should not provide project context traits when copilotcppTraits flag is false.', async () => {
         arrange({
             vscodeExtension: vscodeExtension,
             getIncludeFiles: { includedFiles },
-            chatContext: {
-                language: 'c++',
-                standardVersion: 'c++20',
-                compiler: 'msvc',
-                targetPlatform: 'windows',
-                targetArchitecture: 'x64'
-            },
+            projectContext: projectContextNoArgs,
             rootUri,
             flags: { copilotcppTraits: false }
         });
@@ -148,27 +153,15 @@ describe('registerRelatedFilesProvider', () => {
 
         const result = await callbackPromise;
 
-        ok(vscodeGetExtensionsStub.calledOnce, 'vscode.extensions.getExtension should be called once');
-        ok(mockCopilotApi.registerRelatedFilesProvider.calledWithMatch(sinon.match({ extensionId: 'test-extension-id', languageId: sinon.match.in(['c', 'cpp', 'cuda-cpp']) })), 'registerRelatedFilesProvider should be called with the correct providerId and languageId');
-        ok(getActiveClientStub.callCount !== 0, 'getActiveClient should be called');
-        ok(callbackPromise, 'callbackPromise should be defined');
         ok(result, 'result should be defined');
-        ok(result.entries.length === 1, 'result.entries should have 1 included file');
-        ok(result.entries[0].toString() === expectedInclude, `result.entries should have "${expectedInclude}"`);
         ok(result.traits === undefined, 'result.traits should be undefined');
     });
 
-    it('should add #cpp traits when copilotcppTraits flag is true.', async () => {
+    it('should provide project context traits when copilotcppTraits flag is true.', async () => {
         arrange({
             vscodeExtension: vscodeExtension,
             getIncludeFiles: { includedFiles },
-            chatContext: {
-                language: 'c++',
-                standardVersion: 'c++20',
-                compiler: 'msvc',
-                targetPlatform: 'windows',
-                targetArchitecture: 'x64'
-            },
+            projectContext: projectContextNoArgs,
             rootUri,
             flags: { copilotcppTraits: true }
         });
@@ -176,50 +169,49 @@ describe('registerRelatedFilesProvider', () => {
 
         const result = await callbackPromise;
 
-        ok(vscodeGetExtensionsStub.calledOnce, 'vscode.extensions.getExtension should be called once');
-        ok(mockCopilotApi.registerRelatedFilesProvider.calledThrice, 'registerRelatedFilesProvider should be called three times');
-        ok(mockCopilotApi.registerRelatedFilesProvider.calledWithMatch(sinon.match({ extensionId: 'test-extension-id', languageId: sinon.match.in(['c', 'cpp', 'cuda-cpp']) })), 'registerRelatedFilesProvider should be called with the correct providerId and languageId');
-        ok(getActiveClientStub.callCount !== 0, 'getActiveClient should be called');
-        ok(callbackPromise, 'callbackPromise should be defined');
         ok(result, 'result should be defined');
-        ok(result.entries.length === 1, 'result.entries should have 1 included file');
-        ok(result.entries[0].toString() === expectedInclude, `result.entries should have "${expectedInclude}"`);
         ok(result.traits, 'result.traits should be defined');
-        ok(result.traits.length === 5, 'result.traits should have 5 traits');
-        ok(result.traits[0].name === 'language', 'result.traits[0].name should be "language"');
-        ok(result.traits[0].value === 'c++', 'result.traits[0].value should be "c++"');
-        ok(result.traits[0].includeInPrompt, 'result.traits[0].includeInPrompt should be true');
-        ok(result.traits[0].promptTextOverride === 'The language is c++.', 'result.traits[0].promptTextOverride should be "The language is c++."');
-        ok(result.traits[1].name === 'compiler', 'result.traits[1].name should be "compiler"');
-        ok(result.traits[1].value === 'msvc', 'result.traits[1].value should be "msvc"');
-        ok(result.traits[1].includeInPrompt, 'result.traits[1].includeInPrompt should be true');
-        ok(result.traits[1].promptTextOverride === 'This project compiles using msvc.', 'result.traits[1].promptTextOverride should be "This project compiles using msvc."');
-        ok(result.traits[2].name === 'standardVersion', 'result.traits[2].name should be "standardVersion"');
-        ok(result.traits[2].value === 'c++20', 'result.traits[2].value should be "c++20"');
-        ok(result.traits[2].includeInPrompt, 'result.traits[2].includeInPrompt should be true');
-        ok(result.traits[2].promptTextOverride === 'This project uses the c++20 language standard.', 'result.traits[2].promptTextOverride should be "This project uses the c++20 language standard."');
-        ok(result.traits[3].name === 'targetPlatform', 'result.traits[3].name should be "targetPlatform"');
-        ok(result.traits[3].value === 'windows', 'result.traits[3].value should be "windows"');
-        ok(result.traits[3].includeInPrompt, 'result.traits[3].includeInPrompt should be true');
-        ok(result.traits[3].promptTextOverride === 'This build targets windows.', 'result.traits[3].promptTextOverride should be "This build targets windows."');
-        ok(result.traits[4].name === 'targetArchitecture', 'result.traits[4].name should be "targetArchitecture"');
-        ok(result.traits[4].value === 'x64', 'result.traits[4].value should be "x64"');
-        ok(result.traits[4].includeInPrompt, 'result.traits[4].includeInPrompt should be true');
-        ok(result.traits[4].promptTextOverride === 'This build targets x64.', 'result.traits[4].promptTextOverride should be "This build targets x64."');
+        ok(result.traits.length === 8, 'result.traits should have 6 traits if none are excluded');
+        ok(result.traits.find((trait) => trait.name === 'intellisense'), 'result.traits should have a intellisense trait');
+        ok(result.traits.find((trait) => trait.name === 'intellisense')?.value === 'intellisense', 'result.traits should have a intellisense trait with value "intellisense"');
+        ok(result.traits.find((trait) => trait.name === 'intellisense')?.includeInPrompt, 'result.traits should have a intellisense trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'intellisense')?.promptTextOverride === 'IntelliSense is currently configured with the following compiler information. It reflects the active configuration, and the project may have more configurations targeting different platforms.', 'result.traits should have a intellisense trait with promptTextOverride');
+        ok(result.traits.find((trait) => trait.name === 'intellisenseBegin'), 'result.traits should have a intellisenseBegin trait');
+        ok(result.traits.find((trait) => trait.name === 'intellisenseBegin')?.value === 'Begin', 'result.traits should have a intellisense trait with value "Begin"');
+        ok(result.traits.find((trait) => trait.name === 'intellisenseBegin')?.includeInPrompt, 'result.traits should have a intellisenseBegin trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'intellisenseBegin')?.promptTextOverride === 'Beginning of IntelliSense information.', 'result.traits should have a intellisenseBegin trait with promptTextOverride');
+        ok(result.traits.find((trait) => trait.name === 'language'), 'result.traits should have a language trait');
+        ok(result.traits.find((trait) => trait.name === 'language')?.value === 'C++', 'result.traits should have a language trait with value "C++"');
+        ok(result.traits.find((trait) => trait.name === 'language')?.includeInPrompt, 'result.traits should have a language trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'language')?.promptTextOverride === 'The language is C++.', 'result.traits should have a language trait with promptTextOverride');
+        ok(result.traits.find((trait) => trait.name === 'compiler'), 'result.traits should have a compiler trait');
+        ok(result.traits.find((trait) => trait.name === 'compiler')?.value === 'MSVC', 'result.traits should have a compiler trait with value "MSVC"');
+        ok(result.traits.find((trait) => trait.name === 'compiler')?.includeInPrompt, 'result.traits should have a compiler trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'compiler')?.promptTextOverride === 'This project compiles using MSVC.', 'result.traits should have a compiler trait with promptTextOverride');
+        ok(result.traits.find((trait) => trait.name === 'standardVersion'), 'result.traits should have a standardVersion trait');
+        ok(result.traits.find((trait) => trait.name === 'standardVersion')?.value === 'C++20', 'result.traits should have a standardVersion trait with value "C++20"');
+        ok(result.traits.find((trait) => trait.name === 'standardVersion')?.includeInPrompt, 'result.traits should have a standardVersion trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'standardVersion')?.promptTextOverride === 'This project uses the C++20 language standard.', 'result.traits should have a standardVersion trait with promptTextOverride');
+        ok(result.traits.find((trait) => trait.name === 'targetPlatform'), 'result.traits should have a targetPlatform trait');
+        ok(result.traits.find((trait) => trait.name === 'targetPlatform')?.value === 'Windows', 'result.traits should have a targetPlatform trait with value "Windows"');
+        ok(result.traits.find((trait) => trait.name === 'targetPlatform')?.includeInPrompt, 'result.traits should have a targetPlatform trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'targetPlatform')?.promptTextOverride === 'This build targets Windows.', 'result.traits should have a targetPlatform trait with promptTextOverride');
+        ok(result.traits.find((trait) => trait.name === 'targetArchitecture'), 'result.traits should have a targetArchitecture trait');
+        ok(result.traits.find((trait) => trait.name === 'targetArchitecture')?.value === 'x64', 'result.traits should have a targetArchitecture trait with value "x64"');
+        ok(result.traits.find((trait) => trait.name === 'targetArchitecture')?.includeInPrompt, 'result.traits should have a targetArchitecture trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'targetArchitecture')?.promptTextOverride === 'This build targets x64.', 'result.traits should have a targetArchitecture trait with promptTextOverride');
+        ok(result.traits.find((trait) => trait.name === 'intellisenseEnd'), 'result.traits should have a intellisenseEnd trait');
+        ok(result.traits.find((trait) => trait.name === 'intellisenseEnd')?.value === 'End', 'result.traits should have a intellisense trait with value "End"');
+        ok(result.traits.find((trait) => trait.name === 'intellisenseEnd')?.includeInPrompt, 'result.traits should have a intellisenseEnd trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'intellisenseEnd')?.promptTextOverride === 'End of IntelliSense information.', 'result.traits should have a intellisenseEnd trait with promptTextOverride');
     });
 
-    it('should exclude #cpp traits per copilotcppExcludeTraits.', async () => {
-        const excludeTraits = ['compiler', 'targetPlatform'];
+    it('should exclude project context traits per copilotcppExcludeTraits.', async () => {
+        const excludeTraits = ['compiler', 'targetPlatform', 'intellisense', 'intellisenseBegin', 'intellisenseEnd'];
         arrange({
             vscodeExtension: vscodeExtension,
             getIncludeFiles: { includedFiles },
-            chatContext: {
-                language: 'c++',
-                standardVersion: 'c++20',
-                compiler: 'msvc',
-                targetPlatform: 'windows',
-                targetArchitecture: 'x64'
-            },
+            projectContext: projectContextNoArgs,
             rootUri,
             flags: { copilotcppTraits: true, copilotcppExcludeTraits: excludeTraits }
         });
@@ -233,8 +225,6 @@ describe('registerRelatedFilesProvider', () => {
         ok(getActiveClientStub.callCount !== 0, 'getActiveClient should be called');
         ok(callbackPromise, 'callbackPromise should be defined');
         ok(result, 'result should be defined');
-        ok(result.entries.length === 1, 'result.entries should have 1 included file');
-        ok(result.entries[0].toString() === expectedInclude, `result.entries should have "${expectedInclude}"`);
         ok(result.traits, 'result.traits should be defined');
         ok(result.traits.length === 3, 'result.traits should have 3 traits');
         ok(result.traits.filter(trait => excludeTraits.includes(trait.name)).length === 0, 'result.traits should not include excluded traits');
@@ -248,4 +238,64 @@ describe('registerRelatedFilesProvider', () => {
         ok(vscodeGetExtensionsStub.calledOnce, 'vscode.extensions.getExtension should be called once');
         ok(mockCopilotApi.registerRelatedFilesProvider.notCalled, 'registerRelatedFilesProvider should not be called');
     });
+
+    const projectContext: ProjectContext = {
+        language: 'C++',
+        standardVersion: 'C++20',
+        compiler: 'MSVC',
+        targetPlatform: 'Windows',
+        targetArchitecture: 'x64',
+        compilerArguments: ['/std:c++17', '/GR-', '/EHs-c-', '/await']
+    };
+
+    it('should provide compiler command line traits if available.', async () => {
+        arrange({
+            vscodeExtension: vscodeExtension,
+            getIncludeFiles: { includedFiles: ['c:\\system\\include\\vector', 'c:\\system\\include\\string', 'C:\\src\\my_project\\foo.h'] },
+            projectContext: projectContext,
+            rootUri: vscode.Uri.file('C:\\src\\my_project'),
+            flags: { copilotcppTraits: true }
+        });
+        await moduleUnderTest.registerRelatedFilesProvider();
+
+        const result = await callbackPromise;
+
+        ok(result, 'result should be defined');
+        ok(result.traits, 'result.traits should be defined');
+        ok(result.traits.find((trait) => trait.name === 'compilerArguments'), 'result.traits should have a compiler arguments trait');
+        ok(result.traits.find((trait) => trait.name === 'compilerArguments')?.value === '/std:c++17, /GR-, /EHs-c-, /await', 'result.traits should have a compiler arguments trait with value "/std:c++17, /GR-, /EHs-c-, /await"');
+        ok(result.traits.find((trait) => trait.name === 'compilerArguments')?.includeInPrompt, 'result.traits should have a compiler arguments trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'compilerArguments')?.promptTextOverride === 'The compiler arguments include: /std:c++17, /GR-, /EHs-c-, /await.', 'result.traits should have a compiler arguments trait with promptTextOverride');
+        ok(!result.traits.find((trait) => trait.name === 'directAsks'), 'result.traits should not have a direct asks trait');
+    });
+
+    it('can map compiler arguments to direct asks.', async () => {
+        arrange({
+            vscodeExtension: vscodeExtension,
+            getIncludeFiles: { includedFiles: ['c:\\system\\include\\vector', 'c:\\system\\include\\string', 'C:\\src\\my_project\\foo.h'] },
+            projectContext: projectContext,
+            rootUri: vscode.Uri.file('C:\\src\\my_project'),
+            flags: {
+                copilotcppTraits: true, copilotcppCompilerArgumentDirectAskMap:
+                    JSON.stringify({
+                        '/GR-': 'Do not generate code using RTTI keywords.',
+                        '/EHs-c-': 'Do not generate code using exception handling keywords.'
+                    })
+            }
+        });
+        await moduleUnderTest.registerRelatedFilesProvider();
+
+        const result = await callbackPromise;
+
+        ok(result, 'result should be defined');
+        ok(result.traits, 'result.traits should be defined');
+        ok(result.traits.find((trait) => trait.name === 'compilerArguments'), 'result.traits should have a compiler arguments trait');
+        ok(result.traits.find((trait) => trait.name === 'compilerArguments')?.value === '/std:c++17, /await', 'result.traits should have a compiler arguments trait with value "/std:c++17, /await"');
+        ok(result.traits.find((trait) => trait.name === 'compilerArguments')?.includeInPrompt, 'result.traits should have a compiler arguments trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'compilerArguments')?.promptTextOverride === 'The compiler arguments include: /std:c++17, /await.', 'result.traits should have a compiler arguments trait with promptTextOverride');
+        ok(result.traits.find((trait) => trait.name === 'directAsks'), 'result.traits should have a direct asks trait');
+        ok(result.traits.find((trait) => trait.name === 'directAsks')?.value === 'Do not generate code using RTTI keywords. Do not generate code using exception handling keywords. ', 'result.traits should have a direct asks value');
+        ok(result.traits.find((trait) => trait.name === 'directAsks')?.includeInPrompt, 'result.traits should have a direct asks trait with includeInPrompt true');
+        ok(result.traits.find((trait) => trait.name === 'directAsks')?.promptTextOverride === 'Do not generate code using RTTI keywords. Do not generate code using exception handling keywords. ', 'result.traits should have a direct ask trait with promptTextOverride');
+    });
 });
diff --git a/Extension/test/scenarios/SingleRootProject/tests/lmTool.test.ts b/Extension/test/scenarios/SingleRootProject/tests/lmTool.test.ts
new file mode 100644
index 0000000000..d0a8bc6de4
--- /dev/null
+++ b/Extension/test/scenarios/SingleRootProject/tests/lmTool.test.ts
@@ -0,0 +1,308 @@
+/* --------------------------------------------------------------------------------------------
+ * Copyright (c) Microsoft Corporation. All Rights Reserved.
+ * See 'LICENSE' in the project root for license information.
+ * ------------------------------------------------------------------------------------------ */
+
+import { ok } from 'assert';
+import { afterEach, beforeEach, describe, it } from 'mocha';
+import * as sinon from 'sinon';
+import * as vscode from 'vscode';
+import * as util from '../../../../src/common';
+import { ChatContextResult, DefaultClient, ProjectContextResult } from '../../../../src/LanguageServer/client';
+import { ClientCollection } from '../../../../src/LanguageServer/clientCollection';
+import * as extension from '../../../../src/LanguageServer/extension';
+import { CppConfigurationLanguageModelTool, getProjectContext } from '../../../../src/LanguageServer/lmTool';
+import * as telemetry from '../../../../src/telemetry';
+
+describe('CppConfigurationLanguageModelTool Tests', () => {
+    let mockLanguageModelToolInvocationOptions: sinon.SinonStubbedInstance<vscode.LanguageModelToolInvocationOptions<void>>;
+    let activeClientStub: sinon.SinonStubbedInstance<DefaultClient>;
+    let mockTextEditorStub: MockTextEditor;
+    let mockTextDocumentStub: sinon.SinonStubbedInstance<vscode.TextDocument>;
+    let languageModelToolTelemetryStub: sinon.SinonStub;
+
+    class MockLanguageModelToolInvocationOptions implements vscode.LanguageModelToolInvocationOptions<void> {
+        tokenizationOptions?: vscode.LanguageModelToolTokenizationOptions | undefined;
+        toolInvocationToken: undefined;
+        input: undefined;
+    }
+    class MockTextEditor implements vscode.TextEditor {
+        constructor(selection: vscode.Selection, selections: readonly vscode.Selection[], visibleRanges: readonly vscode.Range[], options: vscode.TextEditorOptions, document: vscode.TextDocument, viewColumn?: vscode.ViewColumn) {
+            this.selection = selection;
+            this.selections = selections;
+            this.visibleRanges = visibleRanges;
+            this.options = options;
+            this.viewColumn = viewColumn;
+            this.document = document;
+        }
+        selection: vscode.Selection;
+        selections: readonly vscode.Selection[];
+        visibleRanges: readonly vscode.Range[];
+        options: vscode.TextEditorOptions;
+        viewColumn: vscode.ViewColumn | undefined;
+        edit(_callback: (editBuilder: vscode.TextEditorEdit) => void, _options?: { readonly undoStopBefore: boolean; readonly undoStopAfter: boolean }): Thenable<boolean> {
+            throw new Error('Method not implemented.');
+        }
+        insertSnippet(_snippet: vscode.SnippetString, _location?: vscode.Position | vscode.Range | readonly vscode.Position[] | readonly vscode.Range[], _options?: { readonly undoStopBefore: boolean; readonly undoStopAfter: boolean }): Thenable<boolean> {
+            throw new Error('Method not implemented.');
+        }
+        setDecorations(_decorationType: vscode.TextEditorDecorationType, _rangesOrOptions: readonly vscode.Range[] | readonly vscode.DecorationOptions[]): void {
+            throw new Error('Method not implemented.');
+        }
+        revealRange(_range: vscode.Range, _revealType?: vscode.TextEditorRevealType): void {
+            throw new Error('Method not implemented.');
+        }
+        show(_column?: vscode.ViewColumn): void {
+            throw new Error('Method not implemented.');
+        }
+        hide(): void {
+            throw new Error('Method not implemented.');
+        }
+        document: vscode.TextDocument;
+    }
+    class MockTextDocument implements vscode.TextDocument {
+        uri: vscode.Uri;
+        constructor(uri: vscode.Uri, fileName: string, isUntitled: boolean, languageId: string, version: number, isDirty: boolean, isClosed: boolean, eol: vscode.EndOfLine, lineCount: number) {
+            this.uri = uri;
+            this.fileName = fileName;
+            this.isUntitled = isUntitled;
+            this.languageId = languageId;
+            this.version = version;
+            this.isDirty = isDirty;
+            this.isClosed = isClosed;
+            this.eol = eol;
+            this.lineCount = lineCount;
+        }
+        fileName: string;
+        isUntitled: boolean;
+        languageId: string;
+        version: number;
+        isDirty: boolean;
+        isClosed: boolean;
+        save(): Thenable<boolean> {
+            throw new Error('Method not implemented.');
+        }
+        eol: vscode.EndOfLine;
+        lineCount: number;
+
+        lineAt(line: number): vscode.TextLine;
+        // eslint-disable-next-line @typescript-eslint/unified-signatures
+        lineAt(position: vscode.Position): vscode.TextLine;
+        lineAt(_arg: number | vscode.Position): vscode.TextLine {
+            throw new Error('Method not implemented.');
+        }
+        offsetAt(_position: vscode.Position): number {
+            throw new Error('Method not implemented.');
+        }
+        positionAt(_offset: number): vscode.Position {
+            throw new Error('Method not implemented.');
+        }
+        getText(_range?: vscode.Range): string {
+            throw new Error('Method not implemented.');
+        }
+        getWordRangeAtPosition(_position: vscode.Position, _regex?: RegExp): vscode.Range | undefined {
+            throw new Error('Method not implemented.');
+        }
+        validateRange(_range: vscode.Range): vscode.Range {
+            throw new Error('Method not implemented.');
+        }
+        validatePosition(_position: vscode.Position): vscode.Position {
+            throw new Error('Method not implemented.');
+        }
+    }
+    beforeEach(() => {
+        sinon.stub(util, 'extensionContext').value({ extension: { id: 'test-extension-id' } });
+
+        mockTextDocumentStub = sinon.createStubInstance(MockTextDocument);
+        mockTextEditorStub = new MockTextEditor(new vscode.Selection(0, 0, 0, 0), [], [], { tabSize: 4 }, mockTextDocumentStub);
+        mockLanguageModelToolInvocationOptions = new MockLanguageModelToolInvocationOptions();
+        activeClientStub = sinon.createStubInstance(DefaultClient);
+        const clientsStub = sinon.createStubInstance(ClientCollection);
+        sinon.stub(extension, 'getClients').returns(clientsStub);
+        sinon.stub(clientsStub, 'ActiveClient').get(() => activeClientStub);
+        activeClientStub.getIncludes.resolves({ includedFiles: [] });
+        sinon.stub(vscode.window, 'activeTextEditor').get(() => mockTextEditorStub);
+        languageModelToolTelemetryStub = sinon.stub(telemetry, 'logLanguageModelToolEvent').returns();
+    });
+
+    afterEach(() => {
+        sinon.restore();
+    });
+
+    const arrangeChatContextFromCppTools = ({ chatContextFromCppTools, isCpp, isHeaderFile }:
+    { chatContextFromCppTools?: ChatContextResult; isCpp?: boolean; isHeaderFile?: boolean } =
+    { chatContextFromCppTools: undefined, isCpp: undefined, isHeaderFile: false }
+    ) => {
+        activeClientStub.getChatContext.resolves(chatContextFromCppTools);
+        sinon.stub(util, 'isCpp').returns(isCpp ?? true);
+        sinon.stub(util, 'isHeaderFile').returns(isHeaderFile ?? false);
+    };
+
+    const arrangeProjectContextFromCppTools = ({ projectContextFromCppTools, isCpp, isHeaderFile }:
+    { projectContextFromCppTools?: ProjectContextResult; isCpp?: boolean; isHeaderFile?: boolean } =
+    { projectContextFromCppTools: undefined, isCpp: undefined, isHeaderFile: false }
+    ) => {
+        activeClientStub.getProjectContext.resolves(projectContextFromCppTools);
+        sinon.stub(util, 'isCpp').returns(isCpp ?? true);
+        sinon.stub(util, 'isHeaderFile').returns(isHeaderFile ?? false);
+    };
+
+    it('should log telemetry and provide #cpp chat context.', async () => {
+        arrangeChatContextFromCppTools({
+            chatContextFromCppTools: {
+                language: 'cpp',
+                standardVersion: 'c++20',
+                compiler: 'msvc',
+                targetPlatform: 'windows',
+                targetArchitecture: 'x64'
+            }
+        });
+
+        const result = await new CppConfigurationLanguageModelTool().invoke(mockLanguageModelToolInvocationOptions, new vscode.CancellationTokenSource().token);
+
+        ok(languageModelToolTelemetryStub.calledOnce, 'logLanguageModelToolEvent should be called once');
+        ok(languageModelToolTelemetryStub.calledWithMatch('Chat/Tool/cpp', sinon.match({
+            "language": 'C++',
+            "compiler": 'MSVC',
+            "standardVersion": 'C++20',
+            "targetPlatform": 'Windows',
+            "targetArchitecture": 'x64'
+        })));
+        ok(result, 'result should not be undefined');
+        const text = result.content[0] as vscode.LanguageModelTextPart;
+        ok(text, 'result should contain a text part');
+        ok(text.value === 'The user is working on a C++ project. The project uses language version C++20. The project compiles using the MSVC compiler. The project targets the Windows platform. The project targets the x64 architecture. ');
+    });
+
+    const testGetProjectContext = async ({
+        compiler,
+        expectedCompiler,
+        context,
+        compilerArguments: compilerArguments,
+        expectedCompilerArguments
+    }: {
+        compiler: string;
+        expectedCompiler: string;
+        context: { flags: Record<string, unknown> };
+        compilerArguments: string[];
+        expectedCompilerArguments: string[];
+    }) => {
+        arrangeProjectContextFromCppTools({
+            projectContextFromCppTools: {
+                language: 'cpp',
+                standardVersion: 'c++20',
+                compiler: compiler,
+                targetPlatform: 'windows',
+                targetArchitecture: 'x64',
+                fileContext: {
+                    compilerArguments: compilerArguments
+                }
+            }
+        });
+
+        const result = await getProjectContext(context, new vscode.CancellationTokenSource().token);
+
+        ok(languageModelToolTelemetryStub.calledOnce, 'logLanguageModelToolEvent should be called once');
+        ok(languageModelToolTelemetryStub.calledWithMatch('Completions/tool', sinon.match({
+            "language": 'C++'
+        })));
+        if (expectedCompiler) {
+            ok(languageModelToolTelemetryStub.calledWithMatch('Completions/tool', sinon.match({
+                "compiler": expectedCompiler
+            })));
+        }
+        ok(languageModelToolTelemetryStub.calledWithMatch('Completions/tool', sinon.match({
+            "standardVersion": 'C++20'
+        })));
+        ok(languageModelToolTelemetryStub.calledWithMatch('Completions/tool', sinon.match({
+            "targetPlatform": 'Windows'
+        })));
+        ok(languageModelToolTelemetryStub.calledWithMatch('Completions/tool', sinon.match({
+            "targetArchitecture": 'x64'
+        })));
+        ok(languageModelToolTelemetryStub.calledWithMatch('Completions/tool', sinon.match({
+            "compilerArgumentCount": compilerArguments.length.toString()
+        })));
+        if (expectedCompilerArguments.length > 0) {
+            ok(languageModelToolTelemetryStub.calledWithMatch('Completions/tool', sinon.match({
+                "filteredCompilerArguments": expectedCompilerArguments.join(', ')
+            })));
+        }
+        ok(languageModelToolTelemetryStub.calledWithMatch('Completions/tool', sinon.match({
+            'time': sinon.match.string
+        })));
+        ok(result, 'result should not be undefined');
+        ok(result.language === 'C++');
+        ok(result.compiler === expectedCompiler);
+        ok(result.standardVersion === 'C++20');
+        ok(result.targetPlatform === 'Windows');
+        ok(result.targetArchitecture === 'x64');
+        ok(JSON.stringify(result.compilerArguments) === JSON.stringify(expectedCompilerArguments));
+    };
+
+    it('should log telemetry and provide cpp context properly when experimental flags are not defined.', async () => {
+        await testGetProjectContext({
+            compiler: 'gcc',
+            expectedCompiler: 'GCC',
+            context: { flags: {} },
+            compilerArguments: ['-Wall', '-Werror', '-std=c++20'],
+            expectedCompilerArguments: []
+        });
+    });
+
+    it('should provide compilerArguments based on copilotcppGccCompilerArgumentFilter.', async () => {
+        await testGetProjectContext({
+            compiler: 'gcc',
+            expectedCompiler: 'GCC',
+            context: { flags: { copilotcppGccCompilerArgumentFilter: '^-(fno\-exceptions|fno\-rtti)$' } },
+            compilerArguments: ['-Wall', '-Werror', '-std=c++20', '-fno-exceptions', '-fno-rtti', '-pthread', '-O3', '-funroll-loops'],
+            expectedCompilerArguments: ['-fno-exceptions', '-fno-rtti']
+        });
+    });
+
+    it('should filter out all compilerArguments for unkonwn compilers.', async () => {
+        await testGetProjectContext({
+            compiler: 'unknown',
+            expectedCompiler: '',
+            context: {
+                flags: {
+                    copilotcppMsvcCompilerArgumentFilter: '^-(fno\-exceptions|fno\-rtti)$',
+                    copilotcppClangCompilerArgumentFilter: '^-(fno\-exceptions|fno\-rtti)$',
+                    copilotcppGccCompilerArgumentFilter: '^-(fno\-exceptions|fno\-rtti)$'
+                }
+            },
+            compilerArguments: ['-fno-exceptions', '-fno-rtti'],
+            expectedCompilerArguments: []
+        });
+    });
+
+    it('should not log telemetry for unknown values', async () => {
+        arrangeProjectContextFromCppTools({
+            projectContextFromCppTools: {
+                language: 'java',
+                standardVersion: 'foo',
+                compiler: 'javac',
+                targetPlatform: 'arduino',
+                targetArchitecture: 'bar',
+                fileContext: {
+                    compilerArguments: []
+                }
+            }
+        });
+
+        const result = await getProjectContext({ flags: {} }, new vscode.CancellationTokenSource().token);
+
+        ok(languageModelToolTelemetryStub.calledOnce, 'logLanguageModelToolEvent should be called once');
+        ok(languageModelToolTelemetryStub.calledWithMatch('Completions/tool', sinon.match({
+            "compilerArgumentCount": '0',
+            "targetArchitecture": 'bar'
+        })));
+        ok(result, 'result should not be undefined');
+        ok(result.language === '');
+        ok(result.compiler === '');
+        ok(result.standardVersion === '');
+        ok(result.targetPlatform === '');
+        ok(result.targetArchitecture === 'bar');
+        ok(result.compilerArguments.length === 0);
+    });
+});