Failed to debug a custom engine agent in Playground

[rickywck]

Describe the bug
I have followed the options and instructions with Microsoft 365 Agents Toolkit to create a LangChain weather agent - I didn't write any code and just took the default generated from the Toolkit. However, I was failed to run the agent even in Playground.

To Reproduce
Steps to reproduce the behavior:

1. Create a custom engine agent with Microsoft 365 Agent Toolkit using VS Code.
2. Select "Weather Agent" and then "OpenAI".
3. Paste the OpenAI key.
4. Select a folder and provide a name of the agent.
5. Agent created. Goto Microsoft 365 Agents Toolkit extension and select "local" under "ENVIRONMENT".
6. Select "Debug in Microsoft 365 Agent Playground".
7. Encounter the following errors: "TypeError: Cannot read properties of undefined (reading 'prototype')
   at 53918 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:2480393)
   at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)
   at 6816 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:313944)
   at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)
   at 32670 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:1544654)
   at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)
   at 23410 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:1201025)
   at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)
   at 62049 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:2750125)
   at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)"

Expected behavior
Can test the generated agent.

Screenshots
If applicable, add screenshots to help explain your problem.

VS Code Extension Information (please complete the following information):

• OS: [e.g. MacOS 15.5]
• Version [e.g. 1.107.1]

Additional context
Add any other context about the problem here.

[m365-agent-toolkit-assistant]

👋 Hi @rickywck,

Thank you for reporting this issue! We want to let you know that:

⏱️ Our team will personally review your issue
🎯 You can expect a response within 2 business days

✨ This is an AI-generated initial response
🤖 AI-Generated Preliminary Analysis:

This error (TypeError: Cannot read properties of undefined (reading 'prototype')) when debugging a custom engine agent in the Microsoft 365 Agents Playground is known and can be related to missing or misconfigured dependencies, especially in the VS Code extension workflow.

Actionable steps:

1. Install env-cmd Globally:
   Run npm install -g env-cmd in your terminal. Many toolkit scripts rely on this package for environment variable management.

2. Verify Toolkit and Extension Versions:
   Ensure you are using the latest Microsoft 365 Agents Toolkit VS Code extension and Playground.

3. Restart VS Code:
   After installing env-cmd, restart VS Code to refresh your environment.

4. Retry Debug:
   Try "Debug in Microsoft 365 Agent Playground" again.

If issues persist, please share:

• Node.js version (node -v)
• Full error logs, not just the stack trace

Reference:
Relevant issue and resolution steps

✨We'd love your feedback! Please take a moment to fill out our survey.

---

Note: This is an automated first response generated by AI. A human team member will review your issue and provide a more detailed response soon. We appreciate your patience!

[rickywck]

Tried step #1, #3 and #4, still got the same error. Node.js version is v25.1.0.

Full logs:
"
[2026-01-08T19:02:06.918Z] [Info] - Current VS Code locale is: en-us
[2026-01-08T19:02:07.508Z] [Info] - Microsoft 365 Agents Toolkit extension is now active!
[2026-01-08T19:02:28.350Z] [Info] - Running 'Validate prerequisites' Visual Studio Code task.

(Total: 2 Steps) Microsoft 365 Agents Toolkit is checking the required prerequisites.

(1/2) Checking Node.js ...
(2/2) Checking ports occupancy ...

Summary:

(√) Done: Node.js version (v25.1.0) is installed
(√) Done: Ports (3978, 9239, 56150) are not occupied

Visit https://aka.ms/teamsfx-tasks/check-prerequisites to get more info about 'Validate prerequisites' task.

[2026-01-08T19:02:28.452Z] [Info] - Finished 'Validate prerequisites' Visual Studio Code task in 0.11 seconds.
[2026-01-08T19:02:28.485Z] [Info] - Executing deploy

Lifecycle stage: deploy(3 step(s) in total). The following actions will be executed:
(1/3) Action devTool/install: installing dependencies
(2/3) Action cli/runNpmCommand: running npm command.
(3/3) Action file/createOrUpdateEnvironmentFile: Create or update variables to env file.

[2026-01-08T19:02:28.485Z] [Info] - Executing lifecycle deploy
[2026-01-08T19:02:32.380Z] [Info] - Finished Executing lifecycle deploy. Result: {}
[2026-01-08T19:02:32.381Z] [Info] - Execution summary:

Summary:
(√) Done: Lifecycle stage deploy was executed successfully.
(√) Done: devTool/install executed successfully.
(√) Done: Microsoft 365 Agents Playground is installed at /Users/ricky.c.wong/AgentsToolkitProjects/copilot-weather/devTools/playground.
(√) Done: cli/runNpmCommand executed successfully.
(√) Done: npm install --no-audit command executed at /Users/ricky.c.wong/AgentsToolkitProjects/copilot-weather/.
(√) Done: file/createOrUpdateEnvironmentFile executed successfully.
(√) Done: Variables have been generated successfully to /Users/ricky.c.wong/AgentsToolkitProjects/copilot-weather/.localConfigs.playground.

[2026-01-08T19:03:48.032Z] [Info] - Running 'Validate prerequisites' Visual Studio Code task.

(Total: 2 Steps) Microsoft 365 Agents Toolkit is checking the required prerequisites.

(1/2) Checking Node.js ...
(2/2) Checking ports occupancy ...

Summary:

(√) Done: Node.js version (v25.1.0) is installed
(√) Done: Ports (3978, 9239, 56150) are not occupied

Visit https://aka.ms/teamsfx-tasks/check-prerequisites to get more info about 'Validate prerequisites' task.

[2026-01-08T19:03:48.112Z] [Info] - Finished 'Validate prerequisites' Visual Studio Code task in 0.08 seconds.
[2026-01-08T19:03:48.147Z] [Info] - Executing deploy

Lifecycle stage: deploy(3 step(s) in total). The following actions will be executed:
(1/3) Action devTool/install: installing dependencies
(2/3) Action cli/runNpmCommand: running npm command.
(3/3) Action file/createOrUpdateEnvironmentFile: Create or update variables to env file.

[2026-01-08T19:03:48.147Z] [Info] - Executing lifecycle deploy
[2026-01-08T19:03:51.843Z] [Info] - Finished Executing lifecycle deploy. Result: {}
[2026-01-08T19:03:51.843Z] [Info] - Execution summary:

Summary:
(√) Done: Lifecycle stage deploy was executed successfully.
(√) Done: devTool/install executed successfully.
(√) Done: Microsoft 365 Agents Playground is installed at /Users/ricky.c.wong/AgentsToolkitProjects/copilot-weather/devTools/playground.
(√) Done: cli/runNpmCommand executed successfully.
(√) Done: npm install --no-audit command executed at /Users/ricky.c.wong/AgentsToolkitProjects/copilot-weather/.
(√) Done: file/createOrUpdateEnvironmentFile executed successfully.
(√) Done: Variables have been generated successfully to /Users/ricky.c.wong/AgentsToolkitProjects/copilot-weather/.localConfigs.playground.

[2026-01-08T19:02:06.918Z] [Info] - Current VS Code locale is: en-us
[2026-01-08T19:02:07.508Z] [Info] - Microsoft 365 Agents Toolkit extension is now active!
[2026-01-08T19:02:28.350Z] [Info] - Running 'Validate prerequisites' Visual Studio Code task.

(Total: 2 Steps) Microsoft 365 Agents Toolkit is checking the required prerequisites.

(1/2) Checking Node.js ...
(2/2) Checking ports occupancy ...

Summary:

(√) Done: Node.js version (v25.1.0) is installed
(√) Done: Ports (3978, 9239, 56150) are not occupied

Visit https://aka.ms/teamsfx-tasks/check-prerequisites to get more info about 'Validate prerequisites' task.

[2026-01-08T19:02:28.452Z] [Info] - Finished 'Validate prerequisites' Visual Studio Code task in 0.11 seconds.
[2026-01-08T19:02:28.485Z] [Info] - Executing deploy

Lifecycle stage: deploy(3 step(s) in total). The following actions will be executed:
(1/3) Action devTool/install: installing dependencies
(2/3) Action cli/runNpmCommand: running npm command.
(3/3) Action file/createOrUpdateEnvironmentFile: Create or update variables to env file.

[2026-01-08T19:02:28.485Z] [Info] - Executing lifecycle deploy
[2026-01-08T19:02:32.380Z] [Info] - Finished Executing lifecycle deploy. Result: {}
[2026-01-08T19:02:32.381Z] [Info] - Execution summary:

Summary:
(√) Done: Lifecycle stage deploy was executed successfully.
(√) Done: devTool/install executed successfully.
(√) Done: Microsoft 365 Agents Playground is installed at /Users/ricky.c.wong/AgentsToolkitProjects/copilot-weather/devTools/playground.
(√) Done: cli/runNpmCommand executed successfully.
(√) Done: npm install --no-audit command executed at /Users/ricky.c.wong/AgentsToolkitProjects/copilot-weather/.
(√) Done: file/createOrUpdateEnvironmentFile executed successfully.
(√) Done: Variables have been generated successfully to /Users/ricky.c.wong/AgentsToolkitProjects/copilot-weather/.localConfigs.playground.

• Executing task: npm run dev:teamsfx:launch-playground

copilotweather@1.0.0 dev:teamsfx:launch-playground
env-cmd --silent -f env/.env.playground agentsplayground start

TypeError: Cannot read properties of undefined (reading 'prototype')
at 53918 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:2480393)
at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)
at 6816 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:313944)
at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)
at 32670 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:1544654)
at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)
at 23410 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:1201025)
at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)
at 62049 (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:2:2750125)
at webpack_require (/opt/homebrew/lib/node_modules/@microsoft/m365agentsplayground/dist/index.js:8:3085)

• The terminal process "/opt/homebrew/bin/zsh '-l', '-c', 'npm run dev:teamsfx:launch-playground'" terminated with exit code: 1.
• Terminal will be reused by tasks, press any key to close it.

"

[rickywck]

Issue fixed after downgrade node to 22

[qinzhouxu]

Issue fixed after downgrade node to 22

Thanks for the issue, we have created an internal backlog to support the latest node version.

[qinzhouxu]

Hi @rickywck , we have fixed related issue in latest version 0.2.24, let me know if the issue persists for node 25.