diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
new file mode 100644
index 0000000000..f300981288
--- /dev/null
+++ b/.github/workflows/pr.yml
@@ -0,0 +1,66 @@
+name: CI
+
+on:
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  test-suite:
+    name: Test suite
+    runs-on: macos-15
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          fetch-depth: 2
+
+      - name: Set up Node.js
+        uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
+        with:
+          node-version: '20'
+          cache: npm
+
+      - name: Enforce package quarantine
+        run: npm run check:package-quarantine
+
+      - name: Install dependencies
+        run: |
+          for attempt in 1 2 3; do
+            npm ci && break
+            if [ "$attempt" -eq 3 ]; then
+              exit 1
+            fi
+          done
+
+      - name: Compile
+        run: npm run compile
+
+      - name: Run hygiene checks
+        run: npm run hygiene
+
+      - name: Run lint
+        run: npm run lint
+
+      - name: Verify command registrations
+        run: npm run check:commands
+
+      - name: Run test suite
+        run: npm run test
+        env:
+          TEST_JUNIT_XML_PATH: ${{ runner.temp }}/test-results.xml
+
+      - name: Publish test summary
+        if: ${{ !cancelled() }}
+        uses: test-summary/action@37b508cfee6d4d080eedd00b5bb240a6a784a6a5 # v2
+        with:
+          paths: ${{ runner.temp }}/*test-results.xml
+
+      - name: Upload test results
+        if: ${{ !cancelled() }}
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
+        with:
+          name: mocha-test-results
+          path: ${{ runner.temp }}/*test-results.xml
diff --git a/azure-pipeline.pr.yml b/azure-pipeline.pr.yml
deleted file mode 100644
index 4eab95d713..0000000000
--- a/azure-pipeline.pr.yml
+++ /dev/null
@@ -1,51 +0,0 @@
-jobs:
-  - job: test_suite
-    displayName: Test suite
-    pool:
-      vmImage: 'macos-15'
-    steps:
-      - checkout: self
-        fetchDepth: 2
-
-      - template: scripts/ci/common-setup.yml
-
-      - script: npm run compile
-        displayName: Compile
-
-      - script: npm run hygiene
-        displayName: Run hygiene checks
-
-      - script: npm run lint
-        displayName: Run lint
-
-      - script: npm run check:commands
-        displayName: Verify command registrations
-
-      - script: npm run test
-        displayName: Run test suite
-        env:
-          TEST_JUNIT_XML_PATH: $(Agent.HomeDirectory)/test-results.xml
-
-      # - script: npm run browsertest --browserType=chromium
-      #   displayName: Run test suite (chromium)
-      #   env:
-      #     TEST_JUNIT_XML_PATH: $(Agent.HomeDirectory)/browser-chromium-test-results.xml
-
-      # - script: npm run browsertest --browserType=firefox
-      #   displayName: Run test suite (firefox)
-      #   env:
-      #     TEST_JUNIT_XML_PATH: $(Agent.HomeDirectory)/browser-firefox-test-results.xml
-
-      # - script: npm run browsertest --browserType=webkit
-      #   displayName: Run test suite (webkit)
-      #   env:
-      #     TEST_JUNIT_XML_PATH: $(Agent.HomeDirectory)/browser-webkit-test-results.xml
-
-      - task: PublishTestResults@2
-        displayName: Publish test results
-        inputs:
-          testResultsFormat: JUnit
-          testResultsFiles: $(Agent.HomeDirectory)/*test-results.xml
-          testRunTitle: Mocha test suite
-          failTaskOnFailedTests: true
-        condition: succeededOrFailed()
diff --git a/build/filters.js b/build/filters.js
index 95672b1ff2..5d96404c5d 100644
--- a/build/filters.js
+++ b/build/filters.js
@@ -44,6 +44,7 @@ module.exports.indentationFilter = [
 	'!**/LICENSE.{txt,rtf}',
 	'!**/LICENSE',
 	'!**/*.yml',
+	'!.github/**/*.yml',
 	'!resources/emojis.json',
 
 	// except multiple specific files
diff --git a/src/@types/vscode.proposed.authIssuers.d.ts b/src/@types/vscode.proposed.authIssuers.d.ts
index c184e42e4d..577bf75858 100644
--- a/src/@types/vscode.proposed.authIssuers.d.ts
+++ b/src/@types/vscode.proposed.authIssuers.d.ts
@@ -4,6 +4,9 @@
  *--------------------------------------------------------------------------------------------*/
 
 declare module 'vscode' {
+
+	// https://github.com/microsoft/vscode/issues/248775
+
 	export interface AuthenticationSession {
 		/**
 		 * The authorization server that issued this session, when provided by the authentication provider.
diff --git a/src/@types/vscode.proposed.chatParticipantAdditions.d.ts b/src/@types/vscode.proposed.chatParticipantAdditions.d.ts
index 46b9977968..3ec459e6ca 100644
--- a/src/@types/vscode.proposed.chatParticipantAdditions.d.ts
+++ b/src/@types/vscode.proposed.chatParticipantAdditions.d.ts
@@ -49,10 +49,15 @@ declare module 'vscode' {
 		ranges: Range[];
 	}
 
+	/** The Auto routing tier a request was resolved with. */
+	export type ChatAutoModeTier = 'efficiency' | 'balance' | 'intelligence' | 'fast';
+
 	export class ChatResponseTextEditPart {
 		uri: Uri;
 		edits: TextEdit[];
 		isDone?: boolean;
+		/** The Auto routing tier that produced these edits, for edit attribution. */
+		autoTier?: ChatAutoModeTier;
 		constructor(uri: Uri, done: true);
 		constructor(uri: Uri, edits: TextEdit | TextEdit[]);
 	}
@@ -61,6 +66,8 @@ declare module 'vscode' {
 		uri: Uri;
 		edits: NotebookEdit[];
 		isDone?: boolean;
+		/** The Auto routing tier that produced these edits, for edit attribution. */
+		autoTier?: ChatAutoModeTier;
 		constructor(uri: Uri, done: true);
 		constructor(uri: Uri, edits: NotebookEdit | NotebookEdit[]);
 	}
diff --git a/src/@types/vscode.proposed.chatSessionsProvider.d.ts b/src/@types/vscode.proposed.chatSessionsProvider.d.ts
index 844de8f23d..ed09833f59 100644
--- a/src/@types/vscode.proposed.chatSessionsProvider.d.ts
+++ b/src/@types/vscode.proposed.chatSessionsProvider.d.ts
@@ -722,6 +722,8 @@ declare module 'vscode' {
 		};
 		readonly maxInputTokens?: number;
 		readonly maxOutputTokens?: number;
+		/** The total context window, independent of the input and output token limits. */
+		readonly maxContextWindowTokens?: number;
 		readonly capabilities?: {
 			readonly vision?: boolean;
 			readonly toolCalling?: boolean;