Bug: MCP Server creation is attempted even when 'Enable MCP Server Creation' setting is disabled

[characharm]

App Version

3.25.6

API Provider

OpenAI Compatible

Model Used

Qwen 3

Roo Code Task Links (Optional)

There appears to be a bug with the RooCode: Enable MCP Server Creation setting. When this setting is unchecked (disabled), AI still attempts to create an MCP server, either by showing a dialog that asks the user to "create a new server" or "use an existing one," or by directly calling the create_mcp_server function.

🔁 Steps to Reproduce

The reproduction steps only require executing a task that involves using an MCP server.

💥 Outcome Summary

When the RooCode: Enable MCP Server Creation setting is disabled, the extension should not make any attempt to create an MCP server.

📄 Relevant Logs or Errors (Optional)

[roomote]

Hi @characharm! I'm here to help out the maintainers and am going to see if I can fix this issue. The bug where MCP Server creation is attempted even when the setting is disabled definitely needs to be addressed. I'll investigate the code and work on a fix. Thanks for reporting this!

[roomote]

I have successfully implemented a fix for this issue in PR #6608.

Summary of Changes

The bug was that the fetch_instructions tool could bypass the enableMcpServerCreation setting and still return MCP server creation instructions even when the setting was disabled.

Root Cause

While the system prompt correctly respected the enableMcpServerCreation setting (via src/core/prompts/sections/mcp-servers.ts), the fetchInstructions function did not check this setting when responding to create_mcp_server task requests.

Solution

1. Modified src/core/prompts/instructions/instructions.ts to check the enableMcpServerCreation setting
2. Updated src/core/tools/fetchInstructionsTool.ts to retrieve and pass the setting value
3. Added comprehensive unit tests to verify the fix

Testing

• All existing tests pass ✅
• New tests verify that MCP server creation instructions are blocked when the setting is disabled ✅
• CI/CD checks have all passed successfully ✅

The fix ensures consistent behavior across all code paths - when enableMcpServerCreation is set to false, the AI cannot create MCP servers through any means.

[characharm]

@roomote-agent Please investigate a different potential root cause for this issue. Instead of checking the fetchInstructions function, could you please check if the create_mcp_server task is hardcoded in the system prompt?
Specifically, please verify if the function getFetchInstructionsDescription unconditionally adds "create_mcp_server" to the description of the fetch_instructions tool. This seems to be the more likely reason why the AI attempts this forbidden action.