Add loopback TCP support for VS Code inproc MCPs - #622
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Matthew Fisher (MicroFish91) merged 17 commits intoOct 1, 2026
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What changed in this PR
Adds optional loopback TCP transport for in-process MCP servers to support VS Code’s Copilot harness while preserving socket-based transport by default.
Changes:
- Starts TCP servers during MCP definition discovery.
- Adds loopback binding, Host/Origin validation, and DNS rebinding protection.
- Reorders package export conditions.
| File | Description |
|---|---|
| packages/vscode-inproc-mcp/src/vscode/registerMcpHttpProvider.ts | Updated as part of this pull request. |
| packages/vscode-inproc-mcp/src/vscode/McpProviderOptions.ts | Updated as part of this pull request. |
| packages/vscode-inproc-mcp/src/vscode/inProcHttpServer.ts | Updated as part of this pull request. |
| packages/vscode-inproc-mcp/package.json | Updated as part of this pull request. |
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Matthew Fisher (MicroFish91)
marked this pull request as draft
September 28, 2026 18:38
Matthew Fisher (MicroFish91)
marked this pull request as ready for review
September 28, 2026 19:01
Brandon Waterloo [MSFT] (bwateratmsft)
previously approved these changes
Oct 1, 2026
Brandon Waterloo [MSFT] (bwateratmsft)
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Brandon Waterloo [MSFT] (bwateratmsft)
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Might need a version bump for release right?
Brandon Waterloo [MSFT] (bwateratmsft)
approved these changes
Oct 1, 2026
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VS Code is transitioning away from their "Local" harness towards the "Copilot" harness which breaks us if we stick with a socket implementation. This gives us a new tcp transport option that we can leverage to keep our MCP support compatible.
Verified socket implementation still works with the local harness and the new tcp implementation works with the Copilot harness.