fix: preserve triple underscores in MCP tool names

[roomote]

Related GitHub Issue

Closes: #10858

Roo Code Task Context (Optional)

This PR was created by Roomote in response to the approved implementation plan.

Description

This PR attempts to address Issue #10858 where MCP aggregators (like 1mcp) use triple underscores (___) in tool names (e.g., playwright___browser_navigate) but Roo Code was incorrectly converting them to hyphens.

Root Cause:
The normalizeMcpToolName() function in src/utils/mcp-name.ts used the regex /__|--/ to split tool names. This regex matched double underscores anywhere, including within triple underscore sequences.

Solution:
Changed the regex to /(?<!_)__(?!_)|--/ which uses negative lookbehind/lookahead to match exactly two underscores that are NOT part of a longer underscore sequence. This preserves triple underscores while still correctly identifying MCP tool separators.

Key changes:

• Modified split regex in normalizeMcpToolName() to preserve ___
• Added comprehensive tests for triple underscore tool names
• Added full flow test for MCP aggregator scenario

Test Procedure

1. Run the unit tests: cd src && npx vitest run utils/__tests__/mcp-name.spec.ts
2. All 66 tests pass, including the new tests specifically for Issue [BUG] MCP tool names with triple underscores (___) are incorrectly converted to hyphens (-) #10858:
   • should preserve triple underscores in tool names (MCP aggregator format)
   • should preserve triple underscores when model converts separators
   • should handle MCP aggregator tool names with triple underscores (Issue #10858)

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue
• Scope: Changes are focused on the linked issue
• Self-Review: Code has been self-reviewed
• Testing: New tests have been added to cover the changes
• Documentation Impact: No documentation updates required
• Contribution Guidelines: Followed contributor guidelines

Screenshots / Videos

N/A - This is a backend logic fix with no UI changes.

Documentation Updates

• No documentation updates are required.

Additional Notes

Feedback and guidance are welcome!

Get in Touch

Roomote Bot

[roomote]

Rooviewer   See task on Roo Cloud

Review complete. No issues found.

The regex change from /__|--/ to /(?<!_)__(?!_)|--/ correctly preserves triple underscores in MCP aggregator tool names while still splitting on double underscores. The implementation is well-tested with comprehensive coverage for edge cases including quadruple underscores and multiple triple underscore segments.

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}