diff --git a/packages/playwright-core/src/server/dispatchers/localUtilsDispatcher.ts b/packages/playwright-core/src/server/dispatchers/localUtilsDispatcher.ts
index 25ba643015..42c73f2d95 100644
--- a/packages/playwright-core/src/server/dispatchers/localUtilsDispatcher.ts
+++ b/packages/playwright-core/src/server/dispatchers/localUtilsDispatcher.ts
@@ -102,7 +102,9 @@ export class LocalUtilsDispatcher extends Dispatcher<{ guid: string }, channels.
       // New file, just compress the entries.
       await fs.promises.mkdir(path.dirname(params.zipFile), { recursive: true });
       zipFile.end(undefined, () => {
-        zipFile.outputStream.pipe(fs.createWriteStream(params.zipFile)).on('close', () => promise.resolve());
+        zipFile.outputStream.pipe(fs.createWriteStream(params.zipFile))
+            .on('close', () => promise.resolve())
+            .on('error', error => promise.reject(error));
       });
       await promise;
       await this._deleteStackSession(params.stacksId);
diff --git a/packages/playwright-core/src/server/trace/recorder/tracing.ts b/packages/playwright-core/src/server/trace/recorder/tracing.ts
index 1656842016..25c5d915c2 100644
--- a/packages/playwright-core/src/server/trace/recorder/tracing.ts
+++ b/packages/playwright-core/src/server/trace/recorder/tracing.ts
@@ -329,7 +329,7 @@ export class Tracing extends SdkObject implements InstrumentationListener, Snaps
       const artifact = new Artifact(this._context, zipFileName);
       artifact.reportFinished();
       result.resolve(artifact);
-    });
+    }).on('error', error => result.reject(error));
     return result;
   }
 
diff --git a/packages/playwright-core/src/utils/traceUtils.ts b/packages/playwright-core/src/utils/traceUtils.ts
index 791744f01f..ca2a27ed59 100644
--- a/packages/playwright-core/src/utils/traceUtils.ts
+++ b/packages/playwright-core/src/utils/traceUtils.ts
@@ -91,7 +91,7 @@ export async function mergeTraceFiles(fileName: string, temporaryTraceFiles: str
       Promise.all(temporaryTraceFiles.map(tempFile => fs.promises.unlink(tempFile))).then(() => {
         mergePromise.resolve();
       });
-    });
+    }).on('error', error => mergePromise.reject(error));
   });
   await mergePromise;
 }
diff --git a/packages/playwright-test/src/isomorphic/teleReceiver.ts b/packages/playwright-test/src/isomorphic/teleReceiver.ts
index fc67985fb4..44d02b0423 100644
--- a/packages/playwright-test/src/isomorphic/teleReceiver.ts
+++ b/packages/playwright-test/src/isomorphic/teleReceiver.ts
@@ -14,11 +14,12 @@
  * limitations under the License.
  */
 
-import type { FullConfig, FullResult, Location, Reporter, TestError, TestResult, TestStatus, TestStep } from '../../types/testReporter';
+import type { FullConfig, FullResult, Location, TestError, TestResult, TestStatus, TestStep } from '../../types/testReporter';
 import type { Annotation } from '../common/config';
 import type { FullProject, Metadata } from '../../types/test';
 import type * as reporterTypes from '../../types/testReporter';
 import type { SuitePrivate } from '../../types/reporterPrivate';
+import type { ReporterV2 } from '../reporters/reporterV2';
 
 export type JsonLocation = Location;
 export type JsonError = string;
@@ -121,14 +122,16 @@ export type JsonEvent = {
 export class TeleReporterReceiver {
   private _rootSuite: TeleSuite;
   private _pathSeparator: string;
-  private _reporter: Reporter;
+  private _reporter: ReporterV2;
   private _tests = new Map<string, TeleTestCase>();
   private _rootDir!: string;
+  private _listOnly = false;
   private _clearPreviousResultsWhenTestBegins: boolean = false;
   private _reuseTestCases: boolean;
   private _reportConfig: MergeReporterConfig | undefined;
+  private _config!: FullConfig;
 
-  constructor(pathSeparator: string, reporter: Reporter, reuseTestCases: boolean, reportConfig?: MergeReporterConfig) {
+  constructor(pathSeparator: string, reporter: ReporterV2, reuseTestCases: boolean, reportConfig?: MergeReporterConfig) {
     this._rootSuite = new TeleSuite('', 'root');
     this._pathSeparator = pathSeparator;
     this._reporter = reporter;
@@ -136,10 +139,14 @@ export class TeleReporterReceiver {
     this._reportConfig = reportConfig;
   }
 
-  dispatch(message: JsonEvent): Promise<void> | undefined {
+  dispatch(message: JsonEvent): Promise<void> | void {
     const { method, params } = message;
+    if (method === 'onConfigure') {
+      this._onConfigure(params.config);
+      return;
+    }
     if (method === 'onBegin') {
-      this._onBegin(params.config, params.projects);
+      this._onBegin(params.projects);
       return;
     }
     if (method === 'onTestBegin') {
@@ -176,8 +183,14 @@ export class TeleReporterReceiver {
     this._clearPreviousResultsWhenTestBegins = true;
   }
 
-  private _onBegin(config: JsonConfig, projects: JsonProject[]) {
+  private _onConfigure(config: JsonConfig) {
     this._rootDir = this._reportConfig?.rootDir || config.rootDir;
+    this._listOnly = config.listOnly;
+    this._config = this._parseConfig(config);
+    this._reporter.onConfigure(this._config);
+  }
+
+  private _onBegin(projects: JsonProject[]) {
     for (const project of projects) {
       let projectSuite = this._rootSuite.suites.find(suite => suite.project()!.id === project.id);
       if (!projectSuite) {
@@ -191,7 +204,7 @@ export class TeleReporterReceiver {
 
       // Remove deleted tests when listing. Empty suites will be auto-filtered
       // in the UI layer.
-      if (config.listOnly) {
+      if (this._listOnly) {
         const testIds = new Set<string>();
         const collectIds = (suite: JsonSuite) => {
           suite.tests.map(t => t.testId).forEach(testId => testIds.add(testId));
@@ -206,7 +219,7 @@ export class TeleReporterReceiver {
         filterTests(projectSuite);
       }
     }
-    this._reporter.onBegin?.(this._parseConfig(config), this._rootSuite);
+    this._reporter.onBegin?.(this._rootSuite);
   }
 
   private _onTestBegin(testId: string, payload: JsonTestResultStart) {
@@ -289,11 +302,11 @@ export class TeleReporterReceiver {
     }
   }
 
-  private _onEnd(result: FullResult): Promise<void> | undefined {
-    return this._reporter.onEnd?.(result) || undefined;
+  private _onEnd(result: FullResult): Promise<void> | void {
+    return this._reporter.onEnd?.(result);
   }
 
-  private _onExit(): Promise<void> | undefined {
+  private _onExit(): Promise<void> | void {
     return this._reporter.onExit?.();
   }
 
diff --git a/packages/playwright-test/src/plugins/index.ts b/packages/playwright-test/src/plugins/index.ts
index 19640084fb..58a1c2477e 100644
--- a/packages/playwright-test/src/plugins/index.ts
+++ b/packages/playwright-test/src/plugins/index.ts
@@ -15,11 +15,11 @@
  */
 
 import type { FullConfig, Suite } from '../../types/testReporter';
-import type { InternalReporter } from '../reporters/internalReporter';
+import type { ReporterV2 } from '../reporters/reporterV2';
 
 export interface TestRunnerPlugin {
   name: string;
-  setup?(config: FullConfig, configDir: string, reporter: InternalReporter): Promise<void>;
+  setup?(config: FullConfig, configDir: string, reporter: ReporterV2): Promise<void>;
   begin?(suite: Suite): Promise<void>;
   end?(): Promise<void>;
   teardown?(): Promise<void>;
diff --git a/packages/playwright-test/src/plugins/webServerPlugin.ts b/packages/playwright-test/src/plugins/webServerPlugin.ts
index f48fa379ed..d381c6c5bd 100644
--- a/packages/playwright-test/src/plugins/webServerPlugin.ts
+++ b/packages/playwright-test/src/plugins/webServerPlugin.ts
@@ -23,7 +23,7 @@ import type { FullConfig } from '../../types/testReporter';
 import type { TestRunnerPlugin } from '.';
 import type { FullConfigInternal } from '../common/config';
 import { envWithoutExperimentalLoaderOptions } from '../util';
-import type { InternalReporter } from '../reporters/internalReporter';
+import type { ReporterV2 } from '../reporters/reporterV2';
 
 
 export type WebServerPluginOptions = {
@@ -50,7 +50,7 @@ export class WebServerPlugin implements TestRunnerPlugin {
   private _processExitedPromise!: Promise<any>;
   private _options: WebServerPluginOptions;
   private _checkPortOnly: boolean;
-  private _reporter?: InternalReporter;
+  private _reporter?: ReporterV2;
   name = 'playwright:webserver';
 
   constructor(options: WebServerPluginOptions, checkPortOnly: boolean) {
@@ -58,7 +58,7 @@ export class WebServerPlugin implements TestRunnerPlugin {
     this._checkPortOnly = checkPortOnly;
   }
 
-  public async setup(config: FullConfig, configDir: string, reporter: InternalReporter) {
+  public async setup(config: FullConfig, configDir: string, reporter: ReporterV2) {
     this._reporter = reporter;
     this._isAvailable = getIsAvailableFunction(this._options.url, this._checkPortOnly, !!this._options.ignoreHTTPSErrors, this._reporter.onStdErr?.bind(this._reporter));
     this._options.cwd = this._options.cwd ? path.resolve(configDir, this._options.cwd) : configDir;
@@ -152,7 +152,7 @@ async function isPortUsed(port: number): Promise<boolean> {
   return await innerIsPortUsed('127.0.0.1') || await innerIsPortUsed('::1');
 }
 
-async function isURLAvailable(url: URL, ignoreHTTPSErrors: boolean, onStdErr: InternalReporter['onStdErr']) {
+async function isURLAvailable(url: URL, ignoreHTTPSErrors: boolean, onStdErr: ReporterV2['onStdErr']) {
   let statusCode = await httpStatusCode(url, ignoreHTTPSErrors, onStdErr);
   if (statusCode === 404 && url.pathname === '/') {
     const indexUrl = new URL(url);
@@ -162,7 +162,7 @@ async function isURLAvailable(url: URL, ignoreHTTPSErrors: boolean, onStdErr: In
   return statusCode >= 200 && statusCode < 404;
 }
 
-async function httpStatusCode(url: URL, ignoreHTTPSErrors: boolean, onStdErr: InternalReporter['onStdErr']): Promise<number> {
+async function httpStatusCode(url: URL, ignoreHTTPSErrors: boolean, onStdErr: ReporterV2['onStdErr']): Promise<number> {
   return new Promise(resolve => {
     debugWebServer(`HTTP GET: ${url}`);
     httpRequest({
@@ -195,7 +195,7 @@ async function waitFor(waitFn: () => Promise<boolean>, cancellationToken: { canc
   }
 }
 
-function getIsAvailableFunction(url: string, checkPortOnly: boolean, ignoreHTTPSErrors: boolean, onStdErr: InternalReporter['onStdErr']) {
+function getIsAvailableFunction(url: string, checkPortOnly: boolean, ignoreHTTPSErrors: boolean, onStdErr: ReporterV2['onStdErr']) {
   const urlObject = new URL(url);
   if (!checkPortOnly)
     return () => isURLAvailable(urlObject, ignoreHTTPSErrors, onStdErr);
diff --git a/packages/playwright-test/src/reporters/base.ts b/packages/playwright-test/src/reporters/base.ts
index 0eb11ad397..7481965c1e 100644
--- a/packages/playwright-test/src/reporters/base.ts
+++ b/packages/playwright-test/src/reporters/base.ts
@@ -118,7 +118,7 @@ export class BaseReporter implements Reporter {
   }
 
   protected generateStartingMessage() {
-    const jobs = this.config.workers;
+    const jobs = this.config.metadata.actualWorkers ?? this.config.workers;
     const shardDetails = this.config.shard ? `, shard ${this.config.shard.current} of ${this.config.shard.total}` : '';
     if (!this.totalTestCount)
       return '';
diff --git a/packages/playwright-test/src/reporters/blob.ts b/packages/playwright-test/src/reporters/blob.ts
index cb8e5b8eb2..6eb33b0536 100644
--- a/packages/playwright-test/src/reporters/blob.ts
+++ b/packages/playwright-test/src/reporters/blob.ts
@@ -57,15 +57,16 @@ export class BlobReporter extends TeleReporterEmitter {
     });
   }
 
-  printsToStdio() {
-    return false;
+  override onConfigure(config: FullConfig) {
+    this._outputDir = path.resolve(this._options.configDir, this._options.outputDir || 'blob-report');
+    this._reportName = this._computeReportName(config);
+    super.onConfigure(config);
   }
 
-  override onBegin(config: FullConfig<{}, {}>, suite: Suite): void {
-    this._outputDir = path.resolve(this._options.configDir, this._options.outputDir || 'blob-report');
+  override onBegin(suite: Suite): void {
+    // Note: config.outputDir is cleared betwee onConfigure and onBegin, so we call mkdir here.
     fs.mkdirSync(path.join(this._outputDir, 'resources'), { recursive: true });
-    this._reportName = this._computeReportName(config);
-    super.onBegin(config, suite);
+    super.onBegin(suite);
   }
 
   override async onEnd(result: FullResult): Promise<void> {
@@ -79,14 +80,16 @@ export class BlobReporter extends TeleReporterEmitter {
     const zipFileName = path.join(this._outputDir, this._reportName + '.zip');
     zipFile.outputStream.pipe(fs.createWriteStream(zipFileName)).on('close', () => {
       zipFinishPromise.resolve(undefined);
-    });
+    }).on('error', error => zipFinishPromise.reject(error));
     zipFile.addReadStream(content, this._reportName + '.jsonl');
     zipFile.end();
 
     await Promise.all([
       ...this._copyFilePromises,
       // Requires Node v14.18.0+
-      zipFinishPromise.catch(e => console.error(`Failed to write report ${zipFileName}: ${e}`))
+      zipFinishPromise.catch(e => {
+        throw new Error(`Failed to write report ${zipFileName}: ` + e.message);
+      }),
     ]);
   }
 
diff --git a/packages/playwright-test/src/reporters/internalReporter.ts b/packages/playwright-test/src/reporters/internalReporter.ts
index 485e01d05b..e7fbff9827 100644
--- a/packages/playwright-test/src/reporters/internalReporter.ts
+++ b/packages/playwright-test/src/reporters/internalReporter.ts
@@ -17,44 +17,29 @@
 import fs from 'fs';
 import { colors } from 'playwright-core/lib/utilsBundle';
 import { codeFrameColumns } from '../transform/babelBundle';
-import type { FullConfig, TestCase, TestError, TestResult, FullResult, TestStep, Reporter } from '../../types/testReporter';
+import type { FullConfig, TestCase, TestError, TestResult, FullResult, TestStep } from '../../types/testReporter';
 import { Suite } from '../common/test';
-import type { FullConfigInternal } from '../common/config';
 import { Multiplexer } from './multiplexer';
 import { prepareErrorStack, relativeFilePath } from './base';
+import type { ReporterV2 } from './reporterV2';
 
-type StdIOChunk = {
-  chunk: string | Buffer;
-  test?: TestCase;
-  result?: TestResult;
-};
-
-export class InternalReporter {
+export class InternalReporter implements ReporterV2 {
   private _multiplexer: Multiplexer;
-  private _deferred: { error?: TestError, stdout?: StdIOChunk, stderr?: StdIOChunk }[] | null = [];
-  private _config!: FullConfigInternal;
+  private _didBegin = false;
+  private _config!: FullConfig;
 
-  constructor(reporters: Reporter[]) {
+  constructor(reporters: ReporterV2[]) {
     this._multiplexer = new Multiplexer(reporters);
   }
 
-  onConfigure(config: FullConfigInternal) {
+  onConfigure(config: FullConfig) {
     this._config = config;
+    this._multiplexer.onConfigure(config);
   }
 
-  onBegin(config: FullConfig, suite: Suite) {
-    this._multiplexer.onBegin(config, suite);
-
-    const deferred = this._deferred!;
-    this._deferred = null;
-    for (const item of deferred) {
-      if (item.error)
-        this.onError(item.error);
-      if (item.stdout)
-        this.onStdOut(item.stdout.chunk, item.stdout.test, item.stdout.result);
-      if (item.stderr)
-        this.onStdErr(item.stderr.chunk, item.stderr.test, item.stderr.result);
-    }
+  onBegin(suite: Suite) {
+    this._didBegin = true;
+    this._multiplexer.onBegin(suite);
   }
 
   onTestBegin(test: TestCase, result: TestResult) {
@@ -62,19 +47,10 @@ export class InternalReporter {
   }
 
   onStdOut(chunk: string | Buffer, test?: TestCase, result?: TestResult) {
-    if (this._deferred) {
-      this._deferred.push({ stdout: { chunk, test, result } });
-      return;
-    }
     this._multiplexer.onStdOut(chunk, test, result);
   }
 
   onStdErr(chunk: string | Buffer, test?: TestCase, result?: TestResult) {
-    if (this._deferred) {
-      this._deferred.push({ stderr: { chunk, test, result } });
-      return;
-    }
-
     this._multiplexer.onStdErr(chunk, test, result);
   }
 
@@ -84,9 +60,9 @@ export class InternalReporter {
   }
 
   async onEnd(result: FullResult) {
-    if (this._deferred) {
+    if (!this._didBegin) {
       // onBegin was not reported, emit it.
-      this.onBegin(this._config.config, new Suite('', 'root'));
+      this.onBegin(new Suite('', 'root'));
     }
     await this._multiplexer.onEnd(result);
   }
@@ -96,11 +72,7 @@ export class InternalReporter {
   }
 
   onError(error: TestError) {
-    if (this._deferred) {
-      this._deferred.push({ error });
-      return;
-    }
-    addLocationAndSnippetToError(this._config.config, error);
+    addLocationAndSnippetToError(this._config, error);
     this._multiplexer.onError(error);
   }
 
@@ -113,14 +85,18 @@ export class InternalReporter {
     this._multiplexer.onStepEnd(test, result, step);
   }
 
+  printsToStdio() {
+    return this._multiplexer.printsToStdio();
+  }
+
   private _addSnippetToTestErrors(test: TestCase, result: TestResult) {
     for (const error of result.errors)
-      addLocationAndSnippetToError(this._config.config, error, test.location.file);
+      addLocationAndSnippetToError(this._config, error, test.location.file);
   }
 
   private _addSnippetToStepError(test: TestCase, step: TestStep) {
     if (step.error)
-      addLocationAndSnippetToError(this._config.config, step.error, test.location.file);
+      addLocationAndSnippetToError(this._config, step.error, test.location.file);
   }
 }
 
diff --git a/packages/playwright-test/src/reporters/merge.ts b/packages/playwright-test/src/reporters/merge.ts
index bb9bf7ece3..8f1fac6d94 100644
--- a/packages/playwright-test/src/reporters/merge.ts
+++ b/packages/playwright-test/src/reporters/merge.ts
@@ -73,13 +73,16 @@ async function extractReportFromZip(file: string): Promise<Buffer> {
 
 async function mergeEvents(dir: string, shardReportFiles: string[]) {
   const events: JsonEvent[] = [];
+  const configureEvents: JsonEvent[] = [];
   const beginEvents: JsonEvent[] = [];
   const endEvents: JsonEvent[] = [];
   for (const reportFile of shardReportFiles) {
     const reportJsonl = await extractReportFromZip(path.join(dir, reportFile));
     const parsedEvents = parseEvents(reportJsonl);
     for (const event of parsedEvents) {
-      if (event.method === 'onBegin')
+      if (event.method === 'onConfigure')
+        configureEvents.push(event);
+      else if (event.method === 'onBegin')
         beginEvents.push(event);
       else if (event.method === 'onEnd')
         endEvents.push(event);
@@ -89,13 +92,12 @@ async function mergeEvents(dir: string, shardReportFiles: string[]) {
         events.push(event);
     }
   }
-  return [mergeBeginEvents(beginEvents), ...events, mergeEndEvents(endEvents), { method: 'onExit', params: undefined }];
+  return [mergeConfigureEvents(configureEvents), mergeBeginEvents(beginEvents), ...events, mergeEndEvents(endEvents), { method: 'onExit', params: undefined }];
 }
 
-function mergeBeginEvents(beginEvents: JsonEvent[]): JsonEvent {
-  if (!beginEvents.length)
-    throw new Error('No begin events found');
-  const projects: JsonProject[] = [];
+function mergeConfigureEvents(configureEvents: JsonEvent[]): JsonEvent {
+  if (!configureEvents.length)
+    throw new Error('No configure events found');
   let config: JsonConfig = {
     configFile: undefined,
     globalTimeout: 0,
@@ -108,8 +110,21 @@ function mergeBeginEvents(beginEvents: JsonEvent[]): JsonEvent {
     workers: 0,
     listOnly: false
   };
-  for (const event of beginEvents) {
+  for (const event of configureEvents)
     config = mergeConfigs(config, event.params.config);
+  return {
+    method: 'onConfigure',
+    params: {
+      config,
+    }
+  };
+}
+
+function mergeBeginEvents(beginEvents: JsonEvent[]): JsonEvent {
+  if (!beginEvents.length)
+    throw new Error('No begin events found');
+  const projects: JsonProject[] = [];
+  for (const event of beginEvents) {
     const shardProjects: JsonProject[] = event.params.projects;
     for (const shardProject of shardProjects) {
       const mergedProject = projects.find(p => p.id === shardProject.id);
@@ -122,7 +137,6 @@ function mergeBeginEvents(beginEvents: JsonEvent[]): JsonEvent {
   return {
     method: 'onBegin',
     params: {
-      config,
       projects,
     }
   };
@@ -136,6 +150,7 @@ function mergeConfigs(to: JsonConfig, from: JsonConfig): JsonConfig {
       ...to.metadata,
       ...from.metadata,
       totalTime: to.metadata.totalTime + from.metadata.totalTime,
+      actualWorkers: (to.metadata.actualWorkers || 0) + (from.metadata.actualWorkers || 0),
     },
     workers: to.workers + from.workers,
   };
diff --git a/packages/playwright-test/src/reporters/multiplexer.ts b/packages/playwright-test/src/reporters/multiplexer.ts
index 2869af396c..48c89f4cee 100644
--- a/packages/playwright-test/src/reporters/multiplexer.ts
+++ b/packages/playwright-test/src/reporters/multiplexer.ts
@@ -14,64 +14,78 @@
  * limitations under the License.
  */
 
-import type { FullConfig, TestCase, TestError, TestResult, FullResult, TestStep, Reporter } from '../../types/testReporter';
+import type { FullConfig, TestCase, TestError, TestResult, FullResult, TestStep } from '../../types/testReporter';
 import type { Suite } from '../common/test';
+import type { ReporterV2 } from './reporterV2';
 
-export class Multiplexer implements Reporter {
-  private _reporters: Reporter[];
+export class Multiplexer implements ReporterV2 {
+  private _reporters: ReporterV2[];
 
-  constructor(reporters: Reporter[]) {
+  constructor(reporters: ReporterV2[]) {
     this._reporters = reporters;
   }
 
-  onBegin(config: FullConfig, suite: Suite) {
+  onConfigure(config: FullConfig) {
     for (const reporter of this._reporters)
-      wrap(() => reporter.onBegin?.(config, suite));
+      wrap(() => reporter.onConfigure(config));
+  }
+
+  onBegin(suite: Suite) {
+    for (const reporter of this._reporters)
+      wrap(() => reporter.onBegin(suite));
   }
 
   onTestBegin(test: TestCase, result: TestResult) {
     for (const reporter of this._reporters)
-      wrap(() => reporter.onTestBegin?.(test, result));
+      wrap(() => reporter.onTestBegin(test, result));
   }
 
   onStdOut(chunk: string | Buffer, test?: TestCase, result?: TestResult) {
     for (const reporter of this._reporters)
-      wrap(() => reporter.onStdOut?.(chunk, test, result));
+      wrap(() => reporter.onStdOut(chunk, test, result));
   }
 
   onStdErr(chunk: string | Buffer, test?: TestCase, result?: TestResult) {
     for (const reporter of this._reporters)
-      wrap(() => reporter.onStdErr?.(chunk, test, result));
+      wrap(() => reporter.onStdErr(chunk, test, result));
   }
 
   onTestEnd(test: TestCase, result: TestResult) {
     for (const reporter of this._reporters)
-      wrap(() => reporter.onTestEnd?.(test, result));
+      wrap(() => reporter.onTestEnd(test, result));
   }
 
   async onEnd(result: FullResult) {
     for (const reporter of this._reporters)
-      await wrapAsync(() => reporter.onEnd?.(result));
+      await wrapAsync(() => reporter.onEnd(result));
   }
 
   async onExit() {
     for (const reporter of this._reporters)
-      await wrapAsync(() => reporter.onExit?.());
+      await wrapAsync(() => reporter.onExit());
   }
 
   onError(error: TestError) {
     for (const reporter of this._reporters)
-      wrap(() => reporter.onError?.(error));
+      wrap(() => reporter.onError(error));
   }
 
   onStepBegin(test: TestCase, result: TestResult, step: TestStep) {
     for (const reporter of this._reporters)
-      wrap(() => reporter.onStepBegin?.(test, result, step));
+      wrap(() => reporter.onStepBegin(test, result, step));
   }
 
   onStepEnd(test: TestCase, result: TestResult, step: TestStep) {
     for (const reporter of this._reporters)
-      wrap(() => reporter.onStepEnd?.(test, result, step));
+      wrap(() => reporter.onStepEnd(test, result, step));
+  }
+
+  printsToStdio(): boolean {
+    return this._reporters.some(r => {
+      let prints = true;
+      wrap(() => prints = r.printsToStdio());
+      return prints;
+    });
   }
 }
 
diff --git a/packages/playwright-test/src/reporters/reporterV2.ts b/packages/playwright-test/src/reporters/reporterV2.ts
new file mode 100644
index 0000000000..6a59c729d5
--- /dev/null
+++ b/packages/playwright-test/src/reporters/reporterV2.ts
@@ -0,0 +1,119 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import type { FullConfig, TestCase, TestError, TestResult, FullResult, TestStep, Reporter, Suite } from '../../types/testReporter';
+
+export interface ReporterV2 {
+  onConfigure(config: FullConfig): void;
+  onBegin(suite: Suite): void;
+  onTestBegin(test: TestCase, result: TestResult): void;
+  onStdOut(chunk: string | Buffer, test?: TestCase, result?: TestResult): void;
+  onStdErr(chunk: string | Buffer, test?: TestCase, result?: TestResult): void;
+  onTestEnd(test: TestCase, result: TestResult): void;
+  onEnd(result: FullResult): void | Promise<void>;
+  onExit(): void | Promise<void>;
+  onError(error: TestError): void;
+  onStepBegin(test: TestCase, result: TestResult, step: TestStep): void;
+  onStepEnd(test: TestCase, result: TestResult, step: TestStep): void;
+  printsToStdio(): boolean;
+}
+
+type StdIOChunk = {
+  chunk: string | Buffer;
+  test?: TestCase;
+  result?: TestResult;
+};
+
+export class ReporterV2Wrapper implements ReporterV2 {
+  private _reporter: Reporter;
+  private _deferred: { error?: TestError, stdout?: StdIOChunk, stderr?: StdIOChunk }[] | null = [];
+  private _config!: FullConfig;
+
+  constructor(reporter: Reporter) {
+    this._reporter = reporter;
+  }
+
+  onConfigure(config: FullConfig) {
+    this._config = config;
+  }
+
+  onBegin(suite: Suite) {
+    this._reporter.onBegin?.(this._config, suite);
+
+    const deferred = this._deferred!;
+    this._deferred = null;
+    for (const item of deferred) {
+      if (item.error)
+        this.onError(item.error);
+      if (item.stdout)
+        this.onStdOut(item.stdout.chunk, item.stdout.test, item.stdout.result);
+      if (item.stderr)
+        this.onStdErr(item.stderr.chunk, item.stderr.test, item.stderr.result);
+    }
+  }
+
+  onTestBegin(test: TestCase, result: TestResult) {
+    this._reporter.onTestBegin?.(test, result);
+  }
+
+  onStdOut(chunk: string | Buffer, test?: TestCase, result?: TestResult) {
+    if (this._deferred) {
+      this._deferred.push({ stdout: { chunk, test, result } });
+      return;
+    }
+    this._reporter.onStdOut?.(chunk, test, result);
+  }
+
+  onStdErr(chunk: string | Buffer, test?: TestCase, result?: TestResult) {
+    if (this._deferred) {
+      this._deferred.push({ stderr: { chunk, test, result } });
+      return;
+    }
+    this._reporter.onStdErr?.(chunk, test, result);
+  }
+
+  onTestEnd(test: TestCase, result: TestResult) {
+    this._reporter.onTestEnd?.(test, result);
+  }
+
+  async onEnd(result: FullResult) {
+    await this._reporter.onEnd?.(result);
+  }
+
+  async onExit() {
+    await this._reporter.onExit?.();
+  }
+
+  onError(error: TestError) {
+    if (this._deferred) {
+      this._deferred.push({ error });
+      return;
+    }
+    this._reporter.onError?.(error);
+  }
+
+  onStepBegin(test: TestCase, result: TestResult, step: TestStep) {
+    this._reporter.onStepBegin?.(test, result, step);
+  }
+
+  onStepEnd(test: TestCase, result: TestResult, step: TestStep) {
+    this._reporter.onStepEnd?.(test, result, step);
+  }
+
+  printsToStdio() {
+    return this._reporter.printsToStdio ? this._reporter.printsToStdio() : true;
+  }
+}
diff --git a/packages/playwright-test/src/reporters/teleEmitter.ts b/packages/playwright-test/src/reporters/teleEmitter.ts
index 338c340cd5..159800c317 100644
--- a/packages/playwright-test/src/reporters/teleEmitter.ts
+++ b/packages/playwright-test/src/reporters/teleEmitter.ts
@@ -17,13 +17,14 @@
 import path from 'path';
 import { createGuid } from 'playwright-core/lib/utils';
 import type { SuitePrivate } from '../../types/reporterPrivate';
-import type { FullConfig, FullResult, Location, Reporter, TestError, TestResult, TestStep } from '../../types/testReporter';
+import type { FullConfig, FullResult, Location, TestError, TestResult, TestStep } from '../../types/testReporter';
 import { FullConfigInternal, FullProjectInternal } from '../common/config';
 import type { Suite, TestCase } from '../common/test';
 import type { JsonAttachment, JsonConfig, JsonEvent, JsonProject, JsonStdIOType, JsonSuite, JsonTestCase, JsonTestEnd, JsonTestResultEnd, JsonTestResultStart, JsonTestStepEnd, JsonTestStepStart } from '../isomorphic/teleReceiver';
 import { serializeRegexPatterns } from '../isomorphic/teleReceiver';
+import type { ReporterV2 } from './reporterV2';
 
-export class TeleReporterEmitter implements Reporter {
+export class TeleReporterEmitter implements ReporterV2 {
   private _messageSink: (message: JsonEvent) => void;
   private _rootDir!: string;
   private _skipBuffers: boolean;
@@ -33,10 +34,14 @@ export class TeleReporterEmitter implements Reporter {
     this._skipBuffers = skipBuffers;
   }
 
-  onBegin(config: FullConfig, suite: Suite) {
+  onConfigure(config: FullConfig) {
     this._rootDir = config.rootDir;
+    this._messageSink({ method: 'onConfigure', params: { config: this._serializeConfig(config) } });
+  }
+
+  onBegin(suite: Suite) {
     const projects = suite.suites.map(projectSuite => this._serializeProject(projectSuite));
-    this._messageSink({ method: 'onBegin', params: { config: this._serializeConfig(config), projects } });
+    this._messageSink({ method: 'onBegin', params: { projects } });
   }
 
   onTestBegin(test: TestCase, result: TestResult): void {
@@ -96,11 +101,11 @@ export class TeleReporterEmitter implements Reporter {
     });
   }
 
-  onStdOut(chunk: string | Buffer, test: void | TestCase, result: void | TestResult): void {
+  onStdOut(chunk: string | Buffer, test?: TestCase, result?: TestResult): void {
     this._onStdIO('stdout', chunk, test, result);
   }
 
-  onStdErr(chunk: string | Buffer, test: void | TestCase, result: void | TestResult): void {
+  onStdErr(chunk: string | Buffer, test?: TestCase, result?: TestResult): void {
     this._onStdIO('stderr', chunk, test, result);
   }
 
@@ -120,6 +125,10 @@ export class TeleReporterEmitter implements Reporter {
   async onExit() {
   }
 
+  printsToStdio() {
+    return false;
+  }
+
   private _serializeConfig(config: FullConfig): JsonConfig {
     return {
       configFile: this._relativePath(config.configFile),
diff --git a/packages/playwright-test/src/runner/dispatcher.ts b/packages/playwright-test/src/runner/dispatcher.ts
index f32e9ab376..00544878e5 100644
--- a/packages/playwright-test/src/runner/dispatcher.ts
+++ b/packages/playwright-test/src/runner/dispatcher.ts
@@ -24,7 +24,7 @@ import { ManualPromise } from 'playwright-core/lib/utils';
 import { WorkerHost } from './workerHost';
 import type { TestGroup } from './testGroups';
 import type { FullConfigInternal } from '../common/config';
-import type { InternalReporter } from '../reporters/internalReporter';
+import type { ReporterV2 } from '../reporters/reporterV2';
 
 type TestResultData = {
   result: TestResult;
@@ -46,14 +46,14 @@ export class Dispatcher {
 
   private _testById = new Map<string, TestData>();
   private _config: FullConfigInternal;
-  private _reporter: InternalReporter;
+  private _reporter: ReporterV2;
   private _hasWorkerErrors = false;
   private _failureCount = 0;
 
   private _extraEnvByProjectId: EnvByProjectId = new Map();
   private _producedEnvByProjectId: EnvByProjectId = new Map();
 
-  constructor(config: FullConfigInternal, reporter: InternalReporter) {
+  constructor(config: FullConfigInternal, reporter: ReporterV2) {
     this._config = config;
     this._reporter = reporter;
   }
diff --git a/packages/playwright-test/src/runner/reporters.ts b/packages/playwright-test/src/runner/reporters.ts
index de3d3af937..b19769415c 100644
--- a/packages/playwright-test/src/runner/reporters.ts
+++ b/packages/playwright-test/src/runner/reporters.ts
@@ -31,9 +31,10 @@ import type { BuiltInReporter, FullConfigInternal } from '../common/config';
 import { loadReporter } from './loadUtils';
 import { BlobReporter } from '../reporters/blob';
 import type { ReporterDescription } from '../../types/test';
+import { type ReporterV2, ReporterV2Wrapper } from '../reporters/reporterV2';
 
-export async function createReporters(config: FullConfigInternal, mode: 'list' | 'run' | 'ui' | 'merge', descriptions?: ReporterDescription[]): Promise<Reporter[]> {
-  const defaultReporters: {[key in BuiltInReporter]: new(arg: any) => Reporter} = {
+export async function createReporters(config: FullConfigInternal, mode: 'list' | 'run' | 'ui' | 'merge', descriptions?: ReporterDescription[]): Promise<ReporterV2[]> {
+  const defaultReporters: { [key in Exclude<BuiltInReporter, 'blob'>]: new(arg: any) => Reporter } = {
     dot: mode === 'list' ? ListModeReporter : DotReporter,
     line: mode === 'list' ? ListModeReporter : LineReporter,
     list: mode === 'list' ? ListModeReporter : ListReporter,
@@ -42,42 +43,40 @@ export async function createReporters(config: FullConfigInternal, mode: 'list' |
     junit: JUnitReporter,
     null: EmptyReporter,
     html: mode === 'ui' ? LineReporter : HtmlReporter,
-    blob: BlobReporter,
     markdown: MarkdownReporter,
   };
-  const reporters: Reporter[] = [];
+  const reporters: ReporterV2[] = [];
   descriptions ??= config.config.reporter;
   for (const r of descriptions) {
     const [name, arg] = r;
     const options = { ...arg, configDir: config.configDir };
-    if (name in defaultReporters) {
-      reporters.push(new defaultReporters[name as keyof typeof defaultReporters](options));
+    if (name === 'blob') {
+      reporters.push(new BlobReporter(options));
+    } else if (name in defaultReporters) {
+      reporters.push(new ReporterV2Wrapper(new defaultReporters[name as keyof typeof defaultReporters](options)));
     } else {
       const reporterConstructor = await loadReporter(config, name);
-      reporters.push(new reporterConstructor(options));
+      reporters.push(new ReporterV2Wrapper(new reporterConstructor(options)));
     }
   }
   if (process.env.PW_TEST_REPORTER) {
     const reporterConstructor = await loadReporter(config, process.env.PW_TEST_REPORTER);
-    reporters.push(new reporterConstructor());
+    reporters.push(new ReporterV2Wrapper(new reporterConstructor()));
   }
 
-  const someReporterPrintsToStdio = reporters.some(r => {
-    const prints = r.printsToStdio ? r.printsToStdio() : true;
-    return prints;
-  });
+  const someReporterPrintsToStdio = reporters.some(r => r.printsToStdio());
   if (reporters.length && !someReporterPrintsToStdio) {
     // Add a line/dot/list-mode reporter for convenience.
     // Important to put it first, jsut in case some other reporter stalls onEnd.
     if (mode === 'list')
-      reporters.unshift(new ListModeReporter());
+      reporters.unshift(new ReporterV2Wrapper(new ListModeReporter()));
     else
-      reporters.unshift(!process.env.CI ? new LineReporter({ omitFailures: true }) : new DotReporter());
+      reporters.unshift(new ReporterV2Wrapper(!process.env.CI ? new LineReporter({ omitFailures: true }) : new DotReporter()));
   }
   return reporters;
 }
 
-export class ListModeReporter implements Reporter {
+class ListModeReporter implements Reporter {
   private config!: FullConfig;
 
   onBegin(config: FullConfig, suite: Suite): void {
diff --git a/packages/playwright-test/src/runner/runner.ts b/packages/playwright-test/src/runner/runner.ts
index 23f6d72b9f..082b2b9529 100644
--- a/packages/playwright-test/src/runner/runner.ts
+++ b/packages/playwright-test/src/runner/runner.ts
@@ -74,7 +74,7 @@ export class Runner {
       : createTaskRunner(config, reporter);
 
     const testRun = new TestRun(config, reporter);
-    reporter.onConfigure(config);
+    reporter.onConfigure(config.config);
 
     if (!listOnly && config.ignoreSnapshots) {
       reporter.onStdOut(colors.dim([
diff --git a/packages/playwright-test/src/runner/taskRunner.ts b/packages/playwright-test/src/runner/taskRunner.ts
index 1cce1089db..98c24f7bf2 100644
--- a/packages/playwright-test/src/runner/taskRunner.ts
+++ b/packages/playwright-test/src/runner/taskRunner.ts
@@ -19,20 +19,20 @@ import { ManualPromise, monotonicTime } from 'playwright-core/lib/utils';
 import type { FullResult, TestError } from '../../reporter';
 import { SigIntWatcher } from './sigIntWatcher';
 import { serializeError } from '../util';
-import type { InternalReporter } from '../reporters/internalReporter';
+import type { ReporterV2 } from '../reporters/reporterV2';
 
 type TaskTeardown = () => Promise<any> | undefined;
 export type Task<Context> = (context: Context, errors: TestError[], softErrors: TestError[]) => Promise<TaskTeardown | void> | undefined;
 
 export class TaskRunner<Context> {
   private _tasks: { name: string, task: Task<Context> }[] = [];
-  private _reporter: InternalReporter;
+  private _reporter: ReporterV2;
   private _hasErrors = false;
   private _interrupted = false;
   private _isTearDown = false;
   private _globalTimeoutForError: number;
 
-  constructor(reporter: InternalReporter, globalTimeoutForError: number) {
+  constructor(reporter: ReporterV2, globalTimeoutForError: number) {
     this._reporter = reporter;
     this._globalTimeoutForError = globalTimeoutForError;
   }
diff --git a/packages/playwright-test/src/runner/tasks.ts b/packages/playwright-test/src/runner/tasks.ts
index d2ba6286aa..49a2963991 100644
--- a/packages/playwright-test/src/runner/tasks.ts
+++ b/packages/playwright-test/src/runner/tasks.ts
@@ -20,7 +20,7 @@ import { promisify } from 'util';
 import { debug, rimraf } from 'playwright-core/lib/utilsBundle';
 import { Dispatcher, type EnvByProjectId } from './dispatcher';
 import type { TestRunnerPluginRegistration } from '../plugins';
-import type { InternalReporter } from '../reporters/internalReporter';
+import type { ReporterV2 } from '../reporters/reporterV2';
 import { createTestGroups, type TestGroup } from '../runner/testGroups';
 import type { Task } from './taskRunner';
 import { TaskRunner } from './taskRunner';
@@ -46,7 +46,7 @@ export type Phase = {
 };
 
 export class TestRun {
-  readonly reporter: InternalReporter;
+  readonly reporter: ReporterV2;
   readonly config: FullConfigInternal;
   rootSuite: Suite | undefined = undefined;
   readonly phases: Phase[] = [];
@@ -55,13 +55,13 @@ export class TestRun {
   projectType: Map<FullProjectInternal, 'top-level' | 'dependency'> = new Map();
   projectSuites: Map<FullProjectInternal, Suite[]> = new Map();
 
-  constructor(config: FullConfigInternal, reporter: InternalReporter) {
+  constructor(config: FullConfigInternal, reporter: ReporterV2) {
     this.config = config;
     this.reporter = reporter;
   }
 }
 
-export function createTaskRunner(config: FullConfigInternal, reporter: InternalReporter): TaskRunner<TestRun> {
+export function createTaskRunner(config: FullConfigInternal, reporter: ReporterV2): TaskRunner<TestRun> {
   const taskRunner = new TaskRunner<TestRun>(reporter, config.config.globalTimeout);
   addGlobalSetupTasks(taskRunner, config);
   taskRunner.addTask('load tests', createLoadTask('in-process', { filterOnly: true, failOnLoadErrors: true }));
@@ -69,13 +69,13 @@ export function createTaskRunner(config: FullConfigInternal, reporter: InternalR
   return taskRunner;
 }
 
-export function createTaskRunnerForWatchSetup(config: FullConfigInternal, reporter: InternalReporter): TaskRunner<TestRun> {
+export function createTaskRunnerForWatchSetup(config: FullConfigInternal, reporter: ReporterV2): TaskRunner<TestRun> {
   const taskRunner = new TaskRunner<TestRun>(reporter, 0);
   addGlobalSetupTasks(taskRunner, config);
   return taskRunner;
 }
 
-export function createTaskRunnerForWatch(config: FullConfigInternal, reporter: InternalReporter, additionalFileMatcher?: Matcher): TaskRunner<TestRun> {
+export function createTaskRunnerForWatch(config: FullConfigInternal, reporter: ReporterV2, additionalFileMatcher?: Matcher): TaskRunner<TestRun> {
   const taskRunner = new TaskRunner<TestRun>(reporter, 0);
   taskRunner.addTask('load tests', createLoadTask('out-of-process', { filterOnly: true, failOnLoadErrors: false, additionalFileMatcher }));
   addRunTasks(taskRunner, config);
@@ -100,7 +100,7 @@ function addRunTasks(taskRunner: TaskRunner<TestRun>, config: FullConfigInternal
   return taskRunner;
 }
 
-export function createTaskRunnerForList(config: FullConfigInternal, reporter: InternalReporter, mode: 'in-process' | 'out-of-process', options: { failOnLoadErrors: boolean }): TaskRunner<TestRun> {
+export function createTaskRunnerForList(config: FullConfigInternal, reporter: ReporterV2, mode: 'in-process' | 'out-of-process', options: { failOnLoadErrors: boolean }): TaskRunner<TestRun> {
   const taskRunner = new TaskRunner<TestRun>(reporter, config.config.globalTimeout);
   taskRunner.addTask('load tests', createLoadTask(mode, { ...options, filterOnly: false }));
   taskRunner.addTask('report begin', createReportBeginTask());
@@ -110,7 +110,7 @@ export function createTaskRunnerForList(config: FullConfigInternal, reporter: In
 function createReportBeginTask(): Task<TestRun> {
   return async ({ config, reporter, rootSuite }) => {
     const montonicStartTime = monotonicTime();
-    reporter.onBegin(config.config, rootSuite!);
+    reporter.onBegin(rootSuite!);
     return async () => {
       config.config.metadata.totalTime = monotonicTime() - montonicStartTime;
     };
@@ -228,7 +228,7 @@ function createPhasesTask(): Task<TestRun> {
       }
     }
 
-    testRun.config.config.workers = Math.min(testRun.config.config.workers, maxConcurrentTestGroups);
+    testRun.config.config.metadata.actualWorkers = Math.min(testRun.config.config.workers, maxConcurrentTestGroups);
   };
 }
 
diff --git a/packages/playwright-test/src/runner/uiMode.ts b/packages/playwright-test/src/runner/uiMode.ts
index 834cc2b0ec..d5b8cc181a 100644
--- a/packages/playwright-test/src/runner/uiMode.ts
+++ b/packages/playwright-test/src/runner/uiMode.ts
@@ -28,6 +28,7 @@ import type { FSWatcher } from 'chokidar';
 import { open } from 'playwright-core/lib/utilsBundle';
 import ListReporter from '../reporters/list';
 import type { OpenTraceViewerOptions, Transport } from 'playwright-core/lib/server/trace/viewer/traceViewer';
+import { ReporterV2Wrapper } from '../reporters/reporterV2';
 
 class UIMode {
   private _config: FullConfigInternal;
@@ -67,9 +68,9 @@ class UIMode {
   }
 
   async runGlobalSetup(): Promise<FullResult['status']> {
-    const reporter = new InternalReporter([new ListReporter()]);
+    const reporter = new InternalReporter([new ReporterV2Wrapper(new ListReporter())]);
     const taskRunner = createTaskRunnerForWatchSetup(this._config, reporter);
-    reporter.onConfigure(this._config);
+    reporter.onConfigure(this._config.config);
     const testRun = new TestRun(this._config, reporter);
     const { status, cleanup: globalCleanup } = await taskRunner.runDeferCleanup(testRun, 0);
     await reporter.onEnd({ status });
@@ -167,7 +168,7 @@ class UIMode {
     const taskRunner = createTaskRunnerForList(this._config, reporter, 'out-of-process', { failOnLoadErrors: false });
     const testRun = new TestRun(this._config, reporter);
     clearCompilationCache();
-    reporter.onConfigure(this._config);
+    reporter.onConfigure(this._config.config);
     const status = await taskRunner.run(testRun, 0);
     await reporter.onEnd({ status });
     await reporter.onExit();
@@ -191,7 +192,7 @@ class UIMode {
     const taskRunner = createTaskRunnerForWatch(this._config, reporter);
     const testRun = new TestRun(this._config, reporter);
     clearCompilationCache();
-    reporter.onConfigure(this._config);
+    reporter.onConfigure(this._config.config);
     const stop = new ManualPromise();
     const run = taskRunner.run(testRun, 0, stop).then(async status => {
       await reporter.onEnd({ status });
diff --git a/packages/playwright-test/src/runner/watchMode.ts b/packages/playwright-test/src/runner/watchMode.ts
index 11d633019e..4bd8ffa52c 100644
--- a/packages/playwright-test/src/runner/watchMode.ts
+++ b/packages/playwright-test/src/runner/watchMode.ts
@@ -31,6 +31,7 @@ import { enquirer } from '../utilsBundle';
 import { separator } from '../reporters/base';
 import { PlaywrightServer } from 'playwright-core/lib/remote/playwrightServer';
 import ListReporter from '../reporters/list';
+import { ReporterV2Wrapper } from '../reporters/reporterV2';
 
 class FSWatcher {
   private _dirtyTestFiles = new Map<FullProjectInternal, Set<string>>();
@@ -112,10 +113,10 @@ export async function runWatchModeLoop(config: FullConfigInternal): Promise<Full
     p.project.retries = 0;
 
   // Perform global setup.
-  const reporter = new InternalReporter([new ListReporter()]);
+  const reporter = new InternalReporter([new ReporterV2Wrapper(new ListReporter())]);
   const testRun = new TestRun(config, reporter);
   const taskRunner = createTaskRunnerForWatchSetup(config, reporter);
-  reporter.onConfigure(config);
+  reporter.onConfigure(config.config);
   const { status, cleanup: globalCleanup } = await taskRunner.runDeferCleanup(testRun, 0);
   if (status !== 'passed')
     await globalCleanup();
@@ -280,11 +281,11 @@ async function runTests(config: FullConfigInternal, failedTestIdCollector: Set<s
     title?: string,
   }) {
   printConfiguration(config, options?.title);
-  const reporter = new InternalReporter([new ListReporter()]);
+  const reporter = new InternalReporter([new ReporterV2Wrapper(new ListReporter())]);
   const taskRunner = createTaskRunnerForWatch(config, reporter, options?.additionalFileMatcher);
   const testRun = new TestRun(config, reporter);
   clearCompilationCache();
-  reporter.onConfigure(config);
+  reporter.onConfigure(config.config);
   const taskStatus = await taskRunner.run(testRun, 0);
   let status: FullResult['status'] = 'passed';
 
diff --git a/packages/trace-viewer/src/ui/uiModeView.tsx b/packages/trace-viewer/src/ui/uiModeView.tsx
index 4fd760d687..28ed64ec06 100644
--- a/packages/trace-viewer/src/ui/uiModeView.tsx
+++ b/packages/trace-viewer/src/ui/uiModeView.tsx
@@ -598,7 +598,7 @@ const refreshRootSuite = (eraseResults: boolean): Promise<void> => {
     return sendMessage('list', {});
 
   let rootSuite: Suite;
-  let loadErrors: TestError[];
+  const loadErrors: TestError[] = [];
   const progress: Progress = {
     passed: 0,
     failed: 0,
@@ -606,12 +606,13 @@ const refreshRootSuite = (eraseResults: boolean): Promise<void> => {
   };
   let config: FullConfig;
   receiver = new TeleReporterReceiver(pathSeparator, {
-    onBegin: (c: FullConfig, suite: Suite) => {
-      if (!rootSuite) {
-        rootSuite = suite;
-        loadErrors = [];
-      }
+    onConfigure: (c: FullConfig) => {
       config = c;
+    },
+
+    onBegin: (suite: Suite) => {
+      if (!rootSuite)
+        rootSuite = suite;
       progress.passed = 0;
       progress.failed = 0;
       progress.skipped = 0;
@@ -639,8 +640,18 @@ const refreshRootSuite = (eraseResults: boolean): Promise<void> => {
     onError: (error: TestError) => {
       xtermDataSource.write((error.stack || error.value || '') + '\n');
       loadErrors.push(error);
-      throttleUpdateRootSuite(config, rootSuite, loadErrors, progress);
+      throttleUpdateRootSuite(config, rootSuite ?? new TeleSuite('', 'root'), loadErrors, progress);
     },
+
+    printsToStdio: () => {
+      return false;
+    },
+
+    onStdOut: () => {},
+    onStdErr: () => {},
+    onExit: () => {},
+    onStepBegin: () => {},
+    onStepEnd: () => {},
   }, true);
   receiver._setClearPreviousResultsWhenTestBegins();
   return sendMessage('list', {});
diff --git a/tests/playwright-test/reporter-blob.spec.ts b/tests/playwright-test/reporter-blob.spec.ts
index 53ad62c7d7..c33b6d47cd 100644
--- a/tests/playwright-test/reporter-blob.spec.ts
+++ b/tests/playwright-test/reporter-blob.spec.ts
@@ -836,8 +836,8 @@ test('preserve config fields', async ({ runInlineTest, mergeReports }) => {
     `
   };
 
-  await runInlineTest(files, { shard: `1/3` });
-  await runInlineTest(files, { shard: `3/3` });
+  await runInlineTest(files, { shard: `1/3`, workers: 1 });
+  await runInlineTest(files, { shard: `3/3`, workers: 1 });
 
   const mergeConfig = {
     reportSlowTests: {