fix: SSE MCP Invocation

[taylorwilsdon]

Related GitHub Issue

Closes: #4241

Description

Fixed the SSE connection issue in McpHub.ts. The problem was that the transport.start override was being applied to all transport types when it should only apply to stdio transports. The fix ensures that SSE and streamable-http transports retain their original start methods while stdio transports get the no-op override after being pre-started.

Test Procedure

Type of Change

• 🐛 Bug Fix: Non-breaking change that fixes an issue.
• ✨ New Feature: Non-breaking change that adds functionality.
• 💥 Breaking Change: Fix or feature that would cause existing functionality to not work as expected.
• ♻️ Refactor: Code change that neither fixes a bug nor adds a feature.
• 💅 Style: Changes that do not affect the meaning of the code (white-space, formatting, etc.).
• 📚 Documentation: Updates to documentation files.
• ⚙️ Build/CI: Changes to the build process or CI configuration.
• 🧹 Chore: Other changes that don't modify src or test files.

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Code Quality:
  • My code adheres to the project's style guidelines.
  • There are no new linting errors or warnings (npm run lint).
  • All debug code (e.g., console.log) has been removed.
• Testing:
  • New and/or updated tests have been added to cover my changes.
  • All tests pass locally (npm test).
  • The application builds successfully with my changes.
• Branch Hygiene: My branch is up-to-date (rebased) with the main branch.
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).
• Changeset: A changeset has been created using npm run changeset if this PR includes user-facing changes or dependency updates.
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Screenshots / Videos

All 3 (stdio, sse, mcp) happy

Documentation Updates

Additional Notes

Get in Touch

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Important

Fixes SSE connection issue in McpHub.ts by ensuring transport.start is only overridden for stdio transports.

• Behavior:
  • Fixes SSE connection issue in McpHub.ts by ensuring transport.start is only overridden for stdio transports.
  • SSE and streamable-http transports retain original start methods.
• Error Handling:
  • Adds onclose handler for transport to update server status to "disconnected" and notify webview.
• Misc:
  • Removes unnecessary connection.server.instructions assignment.

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[taylorwilsdon]

Sorry about that! This should resolve #4241, tested with all 3. Will true up the drift in the other files and push up.

[mrubens]

Thanks for the quick fix!

[taylorwilsdon]

Thanks for the quick fix!

No worries, sorry about that! Was feeling very good about my testing until I realized I don't use any sse endpoints anymore 😂 Had to find a hosted one from cloudflare.