diff --git a/src/runtime/oauth.ts b/src/runtime/oauth.ts
index 8128cc2..ca1e465 100644
--- a/src/runtime/oauth.ts
+++ b/src/runtime/oauth.ts
@@ -19,6 +19,13 @@ export class OAuthTimeoutError extends Error {
   }
 }
 
+export class OAuthCompletedError extends Error {
+  constructor(serverName: string) {
+    super(`OAuth completed for '${serverName}'; reconnect with a fresh transport.`);
+    this.name = 'OAuthCompletedError';
+  }
+}
+
 export async function connectWithAuth(
   client: Client,
   transport: Transport & {
@@ -53,12 +60,16 @@ export async function connectWithAuth(
         );
         if (typeof transport.finishAuth === 'function') {
           await transport.finishAuth(code);
-          logger.info('Authorization code accepted. Retrying connection...');
+          logger.info('Authorization code accepted. Reconnecting with fresh transport...');
+          throw new OAuthCompletedError(serverName ?? 'unknown');
         } else {
           logger.warn('Transport does not support finishAuth; cannot complete OAuth flow automatically.');
           throw error;
         }
       } catch (authError) {
+        if (authError instanceof OAuthCompletedError) {
+          throw authError;
+        }
         logger.error('OAuth authorization failed while waiting for callback.', authError);
         throw authError;
       }
diff --git a/src/runtime/transport.ts b/src/runtime/transport.ts
index 983c3be..7b3c6bb 100644
--- a/src/runtime/transport.ts
+++ b/src/runtime/transport.ts
@@ -11,7 +11,7 @@ import { readCachedAccessToken } from '../oauth-persistence.js';
 import { materializeHeaders } from '../runtime-header-utils.js';
 import { isUnauthorizedError, maybeEnableOAuth } from '../runtime-oauth-support.js';
 import { closeTransportAndWait } from '../runtime-process-utils.js';
-import { connectWithAuth, OAuthTimeoutError } from './oauth.js';
+import { connectWithAuth, OAuthCompletedError, OAuthTimeoutError } from './oauth.js';
 import { resolveCommandArgument, resolveCommandArguments } from './utils.js';
 
 const STDIO_TRACE_ENABLED = process.env.MCPORTER_STDIO_TRACE === '1';
@@ -147,6 +147,13 @@ export async function createClientContext(
       try {
         return await attemptConnect();
       } catch (primaryError) {
+        if (primaryError instanceof OAuthCompletedError) {
+          // OAuth succeeded but the transport is already started; retry with a fresh transport.
+          // Close the current session's callback server to free the port before the next iteration.
+          await oauthSession?.close().catch(() => {});
+          logger.info(`OAuth complete for '${activeDefinition.name}'. Reconnecting...`);
+          continue;
+        }
         if (isUnauthorizedError(primaryError)) {
           await oauthSession?.close().catch(() => {});
           oauthSession = undefined;
diff --git a/tests/runtime-oauth-connect.test.ts b/tests/runtime-oauth-connect.test.ts
index cba76a8..7da4901 100644
--- a/tests/runtime-oauth-connect.test.ts
+++ b/tests/runtime-oauth-connect.test.ts
@@ -5,7 +5,7 @@ import type { JSONRPCMessage } from '@modelcontextprotocol/sdk/types.js';
 import { describe, expect, it, vi } from 'vitest';
 import type { Logger } from '../src/logging.js';
 import type { OAuthSession } from '../src/oauth.js';
-import { connectWithAuth } from '../src/runtime/oauth.js';
+import { connectWithAuth, OAuthCompletedError } from '../src/runtime/oauth.js';
 
 // Minimal mock transport that records finishAuth calls.
 class MockTransport implements Transport {
@@ -23,12 +23,9 @@ class MockTransport implements Transport {
 }
 
 describe('connectWithAuth', () => {
-  it('waits for authorization code and retries connection', async () => {
-    // First connect throws Unauthorized, second succeeds after finishAuth.
-    const connect = vi
-      .fn()
-      .mockRejectedValueOnce(new UnauthorizedError('auth needed'))
-      .mockResolvedValueOnce(undefined);
+  it('throws OAuthCompletedError after successful finishAuth so caller can reconnect', async () => {
+    // connect throws Unauthorized, finishAuth succeeds, then OAuthCompletedError is thrown.
+    const connect = vi.fn().mockRejectedValueOnce(new UnauthorizedError('auth needed'));
     const client = { connect } as unknown as Client;
 
     let resolveCode: (code: string) => void = () => {};
@@ -63,10 +60,10 @@ describe('connectWithAuth', () => {
     // Simulate browser callback arrival.
     resolveCode('oauth-code-123');
 
-    await promise;
+    await expect(promise).rejects.toThrow(OAuthCompletedError);
 
     expect(waitForAuthorizationCode).toHaveBeenCalledTimes(1);
     expect(transport.calls).toEqual(['oauth-code-123']);
-    expect(connect).toHaveBeenCalledTimes(2);
+    expect(connect).toHaveBeenCalledTimes(1);
   });
 });