Failed to connect to MCP servers in v3.23.6: TypeError: Cannot assign to read only property 'all' of object '[object Array]'

[AlgoOy]

App Version

v3.23.6

API Provider

OpenAI Compatible

Model Used

N/A

Roo Code Task Links (Optional)

No response

🔁 Steps to Reproduce

Setup:

OS: macOS (inferred from log file paths)
VS Code Extension: Roo Cline v3.23.6
Actions to trigger the bug:

Install and enable the Roo Cline v3.23.6 extension in Visual Studio Code.
Start or reload VS Code. The extension automatically attempts to initialize its connections to the MCP servers upon startup.
Result:

The extension's initialization process fails.
Multiple error notifications appear, indicating a failure to connect to various MCP servers (Playwright, Tavily, context7, etc.).
The extension's developer console is filled with the same repeating TypeError.

For example:
2025-07-11 14:37:34.120 [error] [Window] [Extension Host] Failed to connect to new MCP server @xxx/mcp: TypeError: Cannot assign to read only property 'all' of object '[object Array]'
at bUr.exports (/Users/xxx/.vscode/extensions/rooveterinaryinc.roo-cline-3.23.6/dist/extension.js:518:112099)
at new Dd (/Users/xxx/.vscode/extensions/rooveterinaryinc.roo-cline-3.23.6/dist/extension.js:518:124974)
at new CBe (/Users/xxx/.vscode/extensions/rooveterinaryinc.roo-cline-3.23.6/dist/extension.js:2828:19800)
at HBe.connectToServer (/Users/xxx/.vscode/extensions/rooveterinaryinc.roo-cline-3.23.6/dist/extension.js:2842:985)
at HBe.updateServerConnections (/Users/xxx/.vscode/extensions/rooveterinaryinc.roo-cline-3.23.6/dist/extension.js:2842:7034)
at HBe.initializeMcpServers (/Users/xxx/.vscode/extensions/rooveterinaryinc.roo-cline-3.23.6/dist/extension.js:2841:851)
at HBe.refreshAllConnections (/Users/xxx/.vscode/extensions/rooveterinaryinc.roo-cline-3.23.6/dist/extension.js:2842:9744)
at V$t (/Users/xxx/.vscode/extensions/rooveterinaryinc.roo-cline-3.23.6/dist/extension.js:5358:18964)

💥 Outcome Summary

Expected MCP server run, but got a lots of TypeError

📄 Relevant Logs or Errors (Optional)

[dosubot]

Hi @AlgoOy! I'm Dosu and I’m helping the Roo-Code team.

I couldn't find any documentation or release notes that mention the "Cannot assign to read only property 'all' of object '[object Array]'" TypeError or MCP server connection failures in Roo Cline v3.23.6. The docs only cover general MCP connection info and troubleshooting, not this specific error or its root cause. There is a note in the v3.8.6 release about reverting SSE MCP support due to configuration validation issues, but nothing directly related to your error or version v3.8.6 release notes.

This TypeError usually means the code is trying to modify a property on an array or object that has been frozen or made read-only, which can happen if the extension is handling shared or immutable data incorrectly during MCP server initialization.

Since this isn't documented, try the following: disable other extensions to rule out conflicts, clear the Roo Cline extension cache, or reinstall the extension. Also, check if there's a newer version available, as this may have been fixed after v3.23.6. If the issue persists, enabling verbose logging or sharing more about your setup could help isolate the cause.

To reply, just mention @dosu.

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[roomote-agent]

PR #5592 has been created to address this issue: #5592

[AlgoOy]

AI is really powerful, haha

[daniel-lxs]

Hey @AlgoOy Could you share your MCP settings making sure you remove sensitive information like paths and API keys?