diff --git a/bootstrap.js b/bootstrap.js
index 69de6fe..b88bc8d 100644
--- a/bootstrap.js
+++ b/bootstrap.js
@@ -1,8 +1,8 @@
-'use strict';
-
+const debug = require('util').debuglog('egg-mock:bootstrap');
 const assert = require('assert');
 const path = require('path');
 const mock = require('./index').default;
+const { setupAgent } = require('./lib/agent');
 const mockParallelApp = require('./lib/parallel/app');
 const { getEggOptions } = require('./lib/utils');
 
@@ -13,8 +13,19 @@ const pkgInfo = require(path.join(options.baseDir || process.cwd(), 'package.jso
 if (pkgInfo.eggPlugin) throw new Error('DO NOT USE bootstrap to test plugin');
 
 let app;
+debug('env.ENABLE_MOCHA_PARALLEL: %s, process.env.AUTO_AGENT: %s',
+  process.env.ENABLE_MOCHA_PARALLEL, process.env.AUTO_AGENT);
 if (process.env.ENABLE_MOCHA_PARALLEL && process.env.AUTO_AGENT) {
-  app = mockParallelApp(options);
+  // setup agent first
+  app = mockParallelApp({
+    ...options,
+    beforeInit: async _app => {
+      const agent = await setupAgent();
+      _app.options.clusterPort = agent.options.clusterPort;
+      debug('mockParallelApp beforeInit get clusterPort: %s', _app.options.clusterPort);
+    },
+  });
+  debug('mockParallelApp app: %s', !!app);
 } else {
   app = mock.app(options);
   if (typeof beforeAll === 'function') {
diff --git a/lib/agent.js b/lib/agent.js
index f261185..7af776a 100644
--- a/lib/agent.js
+++ b/lib/agent.js
@@ -1,9 +1,16 @@
-let agent;
-
+const debug = require('util').debuglog('egg-mock:lib:agent');
 const Agent = require('./parallel/agent');
 const { getEggOptions } = require('./utils');
 
+let agent;
+
 exports.setupAgent = async () => {
+  debug('setupAgent call, env.ENABLE_MOCHA_PARALLEL: %s, process.env.AUTO_AGENT: %s, agent: %s',
+    process.env.ENABLE_MOCHA_PARALLEL, process.env.AUTO_AGENT, !!agent);
+  if (agent) {
+    await agent.ready();
+    return agent;
+  }
   if (process.env.ENABLE_MOCHA_PARALLEL && process.env.AUTO_AGENT) {
     agent = Agent(getEggOptions());
     await agent.ready();
@@ -12,6 +19,7 @@ exports.setupAgent = async () => {
 };
 
 exports.closeAgent = async () => {
+  debug('setupAgent call, agent: %s', !!agent);
   if (agent) {
     await agent.close();
   }
diff --git a/lib/app.js b/lib/app.js
index 1b1daa7..ae10ea3 100644
--- a/lib/app.js
+++ b/lib/app.js
@@ -1,4 +1,4 @@
-const debug = require('util').debuglog('egg-mock');
+const debug = require('util').debuglog('egg-mock:lib:app');
 const os = require('os');
 const path = require('path');
 const EventEmitter = require('events');
diff --git a/lib/parallel/agent.js b/lib/parallel/agent.js
index 95eaa7e..8c2eafb 100644
--- a/lib/parallel/agent.js
+++ b/lib/parallel/agent.js
@@ -1,4 +1,4 @@
-const debug = require('util').debuglog('egg-mock');
+const debug = require('util').debuglog('egg-mock:lib:parallel:agent');
 const path = require('path');
 const Base = require('sdk-base');
 const detectPort = require('detect-port');
diff --git a/lib/parallel/app.js b/lib/parallel/app.js
index a0f1afb..cc92fae 100644
--- a/lib/parallel/app.js
+++ b/lib/parallel/app.js
@@ -1,4 +1,4 @@
-const debug = require('util').debuglog('egg-mock');
+const debug = require('util').debuglog('egg-mock:lib:parallel:app');
 const Base = require('sdk-base');
 const context = require('../context');
 const formatOptions = require('../format_options');
@@ -35,7 +35,10 @@ class MockApplication extends Base {
       delete this.options.beforeInit;
     }
 
-    this.options.clusterPort = process.env.CLUSTER_PORT;
+    this.options.clusterPort = this.options.clusterPort || process.env.CLUSTER_PORT;
+    if (!this.options.clusterPort) {
+      throw new Error('cannot get env.CLUSTER_PORT, parallel run fail');
+    }
     debug('get clusterPort %s', this.options.clusterPort);
     const { Application } = require(this.options.framework);
 
diff --git a/lib/parallel/util.js b/lib/parallel/util.js
index 975c6fa..f0d2e05 100644
--- a/lib/parallel/util.js
+++ b/lib/parallel/util.js
@@ -1,4 +1,4 @@
-const debug = require('util').debuglog('egg-mock');
+const debug = require('util').debuglog('egg-mock:lib:parallel:util');
 const ConsoleLogger = require('egg-logger').EggConsoleLogger;
 const { getProperty } = require('../utils');
 
diff --git a/register.js b/register.js
index 3c8e766..93b3395 100644
--- a/register.js
+++ b/register.js
@@ -1,26 +1,33 @@
+const debug = require('util').debuglog('egg-mock:register');
 const mock = require('./index').default;
 const agent = require('./lib/agent');
 
 exports.mochaGlobalSetup = async () => {
+  debug('mochaGlobalSetup, agent.setupAgent() start');
   await agent.setupAgent();
+  debug('mochaGlobalSetup, agent.setupAgent() end');
 };
 
 exports.mochaGlobalTeardown = async () => {
+  debug('mochaGlobalTeardown, agent.closeAgent() start');
   await agent.closeAgent();
+  debug('mochaGlobalTeardown, agent.closeAgent() end');
 };
 
 let _inited = false;
 let _app;
 exports.mochaHooks = {
   async beforeAll() {
+    debug('mochaHooks.beforeAll call, _inited: %s, _app: %s', _inited, !!_app);
     if (!_inited) {
       _inited = true;
       try {
         const { app } = require('./bootstrap');
         _app = app;
-      } catch {
+      } catch (err) {
         // ignore require error
         // it will throw error on non egg project, e.g.: Error: egg is not found in /foo/bar
+        debug('require bootstrap app error: %s', err);
         return;
       }
       if (_app) {
@@ -29,6 +36,7 @@ exports.mochaHooks = {
     }
   },
   async afterEach() {
+    debug('mochaHooks.afterEach call, _inited: %s, _app: %s', _inited, !!_app);
     if (_app) {
       await _app.backgroundTasksFinished();
     }