diff --git a/build/azure-pipelines/common/checkCopilotChatCompatibility.ts b/build/azure-pipelines/common/checkCopilotChatCompatibility.ts
new file mode 100644
index 00000000000..9c4c12943b9
--- /dev/null
+++ b/build/azure-pipelines/common/checkCopilotChatCompatibility.ts
@@ -0,0 +1,137 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import path from 'path';
+import fs from 'fs';
+import { retry } from './retry.ts';
+import { type IExtensionManifest, parseApiProposalsFromSource, checkExtensionCompatibility, areAllowlistedApiProposalsMatching } from './versionCompatibility.ts';
+
+const root = path.dirname(path.dirname(path.dirname(import.meta.dirname)));
+
+async function fetchLatestExtensionManifest(extensionId: string): Promise<IExtensionManifest> {
+	// Use the vscode-unpkg service to get the latest extension package.json
+	const [publisher, name] = extensionId.split('.');
+
+	// First, get the latest version from the gallery endpoint
+	const galleryUrl = `https://main.vscode-unpkg.net/_gallery/${publisher}/${name}/latest`;
+	const galleryResponse = await fetch(galleryUrl, {
+		headers: { 'User-Agent': 'VSCode Build' }
+	});
+
+	if (!galleryResponse.ok) {
+		throw new Error(`Failed to fetch latest version for ${extensionId}: ${galleryResponse.status} ${galleryResponse.statusText}`);
+	}
+
+	const galleryData = await galleryResponse.json() as { versions: { version: string }[] };
+	const version = galleryData.versions[0].version;
+
+	// Now fetch the package.json using the actual version
+	const url = `https://${publisher}.vscode-unpkg.net/${publisher}/${name}/${version}/extension/package.json`;
+
+	const response = await fetch(url, {
+		headers: { 'User-Agent': 'VSCode Build' }
+	});
+
+	if (!response.ok) {
+		throw new Error(`Failed to fetch extension ${extensionId} from unpkg: ${response.status} ${response.statusText}`);
+	}
+
+	return await response.json() as IExtensionManifest;
+}
+
+export async function checkCopilotChatCompatibility(): Promise<void> {
+	const extensionId = 'github.copilot-chat';
+
+	console.log(`Checking compatibility of ${extensionId}...`);
+
+	// Get product version from package.json
+	const packageJson = JSON.parse(fs.readFileSync(path.join(root, 'package.json'), 'utf8'));
+	const productVersion = packageJson.version;
+
+	console.log(`Product version: ${productVersion}`);
+
+	// Get API proposals from the generated file
+	const apiProposalsPath = path.join(root, 'src/vs/platform/extensions/common/extensionsApiProposals.ts');
+	const apiProposalsContent = fs.readFileSync(apiProposalsPath, 'utf8');
+	const allApiProposals = parseApiProposalsFromSource(apiProposalsContent);
+
+	const proposalCount = Object.keys(allApiProposals).length;
+	if (proposalCount === 0) {
+		throw new Error('Failed to load API proposals from source');
+	}
+
+	console.log(`Loaded ${proposalCount} API proposals from source`);
+
+	// Load product.json to check allowlisted API proposals
+	const productJsonPath = path.join(root, 'product.json');
+	let productJson;
+	try {
+		productJson = JSON.parse(fs.readFileSync(productJsonPath, 'utf8'));
+	} catch (error) {
+		throw new Error(`Failed to load or parse product.json: ${error}`);
+	}
+	const extensionEnabledApiProposals = productJson?.extensionEnabledApiProposals;
+	const extensionIdKey = extensionEnabledApiProposals ? Object.keys(extensionEnabledApiProposals).find(key => key.toLowerCase() === extensionId.toLowerCase()) : undefined;
+	const productAllowlistedProposals = extensionIdKey ? extensionEnabledApiProposals[extensionIdKey] : undefined;
+
+	if (productAllowlistedProposals) {
+		console.log(`Product.json allowlisted proposals for ${extensionId}:`);
+		for (const proposal of productAllowlistedProposals) {
+			console.log(`    ${proposal}`);
+		}
+	} else {
+		console.log(`Product.json allowlisted proposals for ${extensionId}: none`);
+	}
+
+	// Fetch the latest extension manifest
+	const manifest = await retry(() => fetchLatestExtensionManifest(extensionId));
+
+	console.log(`Extension ${extensionId}@${manifest.version}:`);
+	console.log(`  engines.vscode: ${manifest.engines.vscode}`);
+	console.log(`  enabledApiProposals:\n    ${manifest.enabledApiProposals?.join('\n    ') || 'none'}`);
+
+	// Check compatibility
+	const result = checkExtensionCompatibility(productVersion, allApiProposals, manifest);
+	if (!result.compatible) {
+		throw new Error(`Compatibility check failed:\n  ${result.errors.join('\n  ')}`);
+	}
+
+	console.log(`  ✓ Engine version compatible`);
+	if (manifest.enabledApiProposals?.length) {
+		console.log(`  ✓ API proposals compatible`);
+	}
+
+	// Check that product.json allowlist matches package.json declarations
+	const allowlistResult = areAllowlistedApiProposalsMatching(extensionId, productAllowlistedProposals, manifest.enabledApiProposals);
+	if (!allowlistResult.compatible) {
+		throw new Error(`Allowlist check failed:\n  ${allowlistResult.errors.join('\n  ')}`);
+	}
+
+	console.log(`  ✓ Product.json allowlist matches package.json`);
+	console.log(`✓ ${extensionId} is compatible with this build`);
+}
+
+if (import.meta.main) {
+	const warnOnly = process.argv.includes('--warn-only');
+
+	checkCopilotChatCompatibility().then(() => {
+		console.log('Copilot Chat compatibility check passed');
+		process.exit(0);
+	}, err => {
+		if (warnOnly) {
+			// Issue a warning using Azure DevOps logging commands but don't fail the build
+			console.log(`##vso[task.logissue type=warning]Copilot Chat compatibility check failed: ${err.message}`);
+			console.log(`##vso[task.complete result=SucceededWithIssues;]Copilot Chat compatibility check failed`);
+			console.log('');
+			console.log(`⚠️  WARNING: ${err.message}`);
+			console.log('');
+			console.log('The build will continue, but the release step will fail if this is not resolved.');
+			process.exit(0);
+		} else {
+			console.error(err);
+			process.exit(1);
+		}
+	});
+}
diff --git a/build/azure-pipelines/common/checkDistroCommit.ts b/build/azure-pipelines/common/checkDistroCommit.ts
new file mode 100644
index 00000000000..4003a10df31
--- /dev/null
+++ b/build/azure-pipelines/common/checkDistroCommit.ts
@@ -0,0 +1,112 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import path from 'path';
+import fs from 'fs';
+import { retry } from './retry.ts';
+
+const root = path.dirname(path.dirname(path.dirname(import.meta.dirname)));
+
+function getEnv(name: string): string {
+	const result = process.env[name];
+
+	if (typeof result === 'undefined') {
+		throw new Error('Missing env: ' + name);
+	}
+
+	return result;
+}
+
+interface GitHubBranchResponse {
+	commit: {
+		sha: string;
+	};
+}
+
+async function getDistroBranchHead(branch: string, token: string): Promise<string> {
+	const url = `https://api.github.com/repos/microsoft/vscode-distro/branches/${encodeURIComponent(branch)}`;
+
+	const response = await fetch(url, {
+		headers: {
+			'Accept': 'application/vnd.github+json',
+			'Authorization': `Bearer ${token}`,
+			'X-GitHub-Api-Version': '2022-11-28',
+			'User-Agent': 'VSCode Build'
+		}
+	});
+
+	if (!response.ok) {
+		throw new Error(`Failed to fetch branch ${branch} from vscode-distro: ${response.status} ${response.statusText}`);
+	}
+
+	const data = await response.json() as GitHubBranchResponse;
+	return data.commit.sha;
+}
+
+async function checkDistroCommit(): Promise<void> {
+	// Get the distro commit from package.json
+	const packageJsonPath = path.join(root, 'package.json');
+	const packageJson = JSON.parse(fs.readFileSync(packageJsonPath, 'utf8'));
+	const distroCommit: string = packageJson.distro;
+
+	if (!distroCommit) {
+		console.log('No distro commit found in package.json, skipping check');
+		return;
+	}
+
+	console.log(`Distro commit in package.json: ${distroCommit}`);
+
+	// Get the current branch from Azure DevOps
+	// BUILD_SOURCEBRANCH is in format refs/heads/main or refs/heads/release/1.90
+	const sourceBranch = getEnv('BUILD_SOURCEBRANCH');
+	const branchMatch = sourceBranch.match(/^refs\/heads\/(.+)$/);
+
+	if (!branchMatch) {
+		console.log(`Cannot determine branch from BUILD_SOURCEBRANCH: ${sourceBranch}, skipping check`);
+		return;
+	}
+
+	const branch = branchMatch[1];
+	console.log(`Current branch: ${branch}`);
+
+	// Get the GitHub token
+	const token = getEnv('GITHUB_TOKEN');
+
+	// Fetch the HEAD of the matching branch in vscode-distro
+	let distroBranchHead: string;
+	try {
+		distroBranchHead = await retry(() => getDistroBranchHead(branch, token));
+	} catch (error) {
+		// If the branch doesn't exist in distro, that's expected for feature branches
+		console.log(`Could not fetch branch '${branch}' from vscode-distro: ${error}`);
+		console.log('This is expected for feature branches that have not been merged to distro');
+		return;
+	}
+
+	console.log(`Distro branch '${branch}' HEAD: ${distroBranchHead}`);
+
+	// Compare the commits
+	if (distroCommit === distroBranchHead) {
+		console.log(`✓ Distro commit matches branch HEAD`);
+	} else {
+		// Issue a warning using Azure DevOps logging commands
+		console.log(`##vso[task.logissue type=warning]Distro commit mismatch: package.json has ${distroCommit.substring(0, 8)} but ${branch} HEAD is ${distroBranchHead.substring(0, 8)}`);
+		console.log(`##vso[task.complete result=SucceededWithIssues;]Distro commit does not match branch HEAD`);
+		console.log('');
+		console.log(`⚠️  WARNING: Distro commit in package.json does not match the HEAD of branch '${branch}' in vscode-distro`);
+		console.log(`   package.json distro: ${distroCommit}`);
+		console.log(`   ${branch} HEAD:      ${distroBranchHead}`);
+		console.log('');
+		console.log('   To update, run: npm run update-distro');
+	}
+}
+
+checkDistroCommit().then(() => {
+	console.log('Distro commit check completed');
+	process.exit(0);
+}, err => {
+	console.error(err);
+	process.exit(1);
+});
diff --git a/build/azure-pipelines/common/releaseBuild.ts b/build/azure-pipelines/common/releaseBuild.ts
index 37e869a42bc..3cd8082308e 100644
--- a/build/azure-pipelines/common/releaseBuild.ts
+++ b/build/azure-pipelines/common/releaseBuild.ts
@@ -4,12 +4,8 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { CosmosClient } from '@azure/cosmos';
-import path from 'path';
-import fs from 'fs';
 import { retry } from './retry.ts';
-import { type IExtensionManifest, parseApiProposalsFromSource, checkExtensionCompatibility, areAllowlistedApiProposalsMatching } from './versionCompatibility.ts';
-
-const root = path.dirname(path.dirname(path.dirname(import.meta.dirname)));
+import { checkCopilotChatCompatibility } from './checkCopilotChatCompatibility.ts';
 
 function getEnv(name: string): string {
 	const result = process.env[name];
@@ -21,109 +17,6 @@ function getEnv(name: string): string {
 	return result;
 }
 
-async function fetchLatestExtensionManifest(extensionId: string): Promise<IExtensionManifest> {
-	// Use the vscode-unpkg service to get the latest extension package.json
-	const [publisher, name] = extensionId.split('.');
-
-	// First, get the latest version from the gallery endpoint
-	const galleryUrl = `https://main.vscode-unpkg.net/_gallery/${publisher}/${name}/latest`;
-	const galleryResponse = await fetch(galleryUrl, {
-		headers: { 'User-Agent': 'VSCode Build' }
-	});
-
-	if (!galleryResponse.ok) {
-		throw new Error(`Failed to fetch latest version for ${extensionId}: ${galleryResponse.status} ${galleryResponse.statusText}`);
-	}
-
-	const galleryData = await galleryResponse.json() as { versions: { version: string }[] };
-	const version = galleryData.versions[0].version;
-
-	// Now fetch the package.json using the actual version
-	const url = `https://${publisher}.vscode-unpkg.net/${publisher}/${name}/${version}/extension/package.json`;
-
-	const response = await fetch(url, {
-		headers: { 'User-Agent': 'VSCode Build' }
-	});
-
-	if (!response.ok) {
-		throw new Error(`Failed to fetch extension ${extensionId} from unpkg: ${response.status} ${response.statusText}`);
-	}
-
-	return await response.json() as IExtensionManifest;
-}
-
-async function checkCopilotChatCompatibility(): Promise<void> {
-	const extensionId = 'github.copilot-chat';
-
-	console.log(`Checking compatibility of ${extensionId}...`);
-
-	// Get product version from package.json
-	const packageJson = JSON.parse(fs.readFileSync(path.join(root, 'package.json'), 'utf8'));
-	const productVersion = packageJson.version;
-
-	console.log(`Product version: ${productVersion}`);
-
-	// Get API proposals from the generated file
-	const apiProposalsPath = path.join(root, 'src/vs/platform/extensions/common/extensionsApiProposals.ts');
-	const apiProposalsContent = fs.readFileSync(apiProposalsPath, 'utf8');
-	const allApiProposals = parseApiProposalsFromSource(apiProposalsContent);
-
-	const proposalCount = Object.keys(allApiProposals).length;
-	if (proposalCount === 0) {
-		throw new Error('Failed to load API proposals from source');
-	}
-
-	console.log(`Loaded ${proposalCount} API proposals from source`);
-
-	// Load product.json to check allowlisted API proposals
-	const productJsonPath = path.join(root, 'product.json');
-	let productJson;
-	try {
-		productJson = JSON.parse(fs.readFileSync(productJsonPath, 'utf8'));
-	} catch (error) {
-		throw new Error(`Failed to load or parse product.json: ${error}`);
-	}
-	const extensionEnabledApiProposals = productJson?.extensionEnabledApiProposals;
-	const extensionIdKey = extensionEnabledApiProposals ? Object.keys(extensionEnabledApiProposals).find(key => key.toLowerCase() === extensionId.toLowerCase()) : undefined;
-	const productAllowlistedProposals = extensionIdKey ? extensionEnabledApiProposals[extensionIdKey] : undefined;
-
-	if (productAllowlistedProposals) {
-		console.log(`Product.json allowlisted proposals for ${extensionId}:`);
-		for (const proposal of productAllowlistedProposals) {
-			console.log(`    ${proposal}`);
-		}
-	} else {
-		console.log(`Product.json allowlisted proposals for ${extensionId}: none`);
-	}
-
-	// Fetch the latest extension manifest
-	const manifest = await retry(() => fetchLatestExtensionManifest(extensionId));
-
-	console.log(`Extension ${extensionId}@${manifest.version}:`);
-	console.log(`  engines.vscode: ${manifest.engines.vscode}`);
-	console.log(`  enabledApiProposals:\n    ${manifest.enabledApiProposals?.join('\n    ') || 'none'}`);
-
-	// Check compatibility
-	const result = checkExtensionCompatibility(productVersion, allApiProposals, manifest);
-	if (!result.compatible) {
-		throw new Error(`Compatibility check failed:\n  ${result.errors.join('\n  ')}`);
-	}
-
-	console.log(`  ✓ Engine version compatible`);
-	if (manifest.enabledApiProposals?.length) {
-		console.log(`  ✓ API proposals compatible`);
-	}
-
-	// Check that product.json allowlist matches package.json declarations
-	const allowlistResult = areAllowlistedApiProposalsMatching(extensionId, productAllowlistedProposals, manifest.enabledApiProposals);
-	if (!allowlistResult.compatible) {
-		throw new Error(`Allowlist check failed:\n  ${allowlistResult.errors.join('\n  ')}`);
-	}
-
-	console.log(`  ✓ Product.json allowlist matches package.json`);
-	console.log(`✓ ${extensionId} is compatible with this build`);
-}
-
 interface Config {
 	id: string;
 	frozen: boolean;
diff --git a/build/azure-pipelines/product-build.yml b/build/azure-pipelines/product-build.yml
index 3ff40d1d941..897c27e680d 100644
--- a/build/azure-pipelines/product-build.yml
+++ b/build/azure-pipelines/product-build.yml
@@ -203,6 +203,15 @@ extends:
         jobs:
           - template: build/azure-pipelines/product-compile.yml@self
 
+      - ${{ if eq(variables['VSCODE_PUBLISH'], 'true') }}:
+        - stage: ValidationChecks
+          dependsOn: []
+          pool:
+            name: 1es-ubuntu-22.04-x64
+            os: linux
+          jobs:
+            - template: build/azure-pipelines/product-validation-checks.yml@self
+
       - ${{ if or(eq(parameters.VSCODE_BUILD_LINUX, true),eq(parameters.VSCODE_BUILD_LINUX_ARMHF, true),eq(parameters.VSCODE_BUILD_LINUX_ARM64, true),eq(parameters.VSCODE_BUILD_ALPINE, true),eq(parameters.VSCODE_BUILD_ALPINE_ARM64, true),eq(parameters.VSCODE_BUILD_MACOS, true),eq(parameters.VSCODE_BUILD_MACOS_ARM64, true),eq(parameters.VSCODE_BUILD_WIN32, true),eq(parameters.VSCODE_BUILD_WIN32_ARM64, true)) }}:
         - stage: CompileCLI
           dependsOn: []
diff --git a/build/azure-pipelines/product-validation-checks.yml b/build/azure-pipelines/product-validation-checks.yml
new file mode 100644
index 00000000000..adf61f33c42
--- /dev/null
+++ b/build/azure-pipelines/product-validation-checks.yml
@@ -0,0 +1,40 @@
+jobs:
+  - job: ValidationChecks
+    displayName: Distro and Extension Validation
+    timeoutInMinutes: 15
+    steps:
+      - template: ./common/checkout.yml@self
+
+      - task: NodeTool@0
+        inputs:
+          versionSource: fromFile
+          versionFilePath: .nvmrc
+
+      - template: ./distro/download-distro.yml@self
+
+      - script: node build/azure-pipelines/distro/mixin-quality.ts
+        displayName: Mixin distro quality
+
+      - task: AzureKeyVault@2
+        displayName: "Azure Key Vault: Get Secrets"
+        inputs:
+          azureSubscription: vscode
+          KeyVaultName: vscode-build-secrets
+          SecretsFilter: "github-distro-mixin-password"
+
+      - script: npm ci
+        workingDirectory: build
+        env:
+          GITHUB_TOKEN: "$(github-distro-mixin-password)"
+        displayName: Install build dependencies
+
+      - script: node build/azure-pipelines/common/checkDistroCommit.ts
+        displayName: Check distro commit
+        env:
+          GITHUB_TOKEN: "$(github-distro-mixin-password)"
+          BUILD_SOURCEBRANCH: "$(Build.SourceBranch)"
+        continueOnError: true
+
+      - script: node build/azure-pipelines/common/checkCopilotChatCompatibility.ts --warn-only
+        displayName: Check Copilot Chat compatibility
+        continueOnError: true