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@roomote roomote bot commented Sep 3, 2025

Summary

This PR addresses Issue #7639 by ensuring MCP server errors are properly surfaced to users through VS Code's notification system, rather than only being logged to the console.

Problem

Previously, when MCP server connections failed (invalid URLs, transport errors, etc.), errors were only logged via console.error without any visible UI indication. This resulted in silent failures that appeared as no-ops to users.

Solution

Updated the error handling in McpHub.ts to display errors using vscode.window.showErrorMessage() in addition to console logging:

  1. Updated showErrorMessage method: Now calls vscode.window.showErrorMessage to display toast notifications
  2. Fixed transport error handlers: Added UI error notifications for all transport types:
    • stdio transport errors
    • SSE transport errors
    • streamable-http transport errors

Changes

  • Modified src/services/mcp/McpHub.ts:
    • Updated showErrorMessage() helper to display UI notifications
    • Added vscode.window.showErrorMessage() calls to all transport error handlers
    • Maintains console logging for debugging while adding user-facing notifications

Testing

  • All existing tests pass (42 tests in MCP test suite)
  • Linting passes
  • Type checking passes
  • Code review confidence: 95%

Impact

Users will now receive clear, visible error notifications when:

  • MCP server connections fail
  • Invalid URLs are configured
  • Transport errors occur during refresh/reconnect
  • Any other MCP-related errors that were previously silent

Fixes #7639


Important

Enhance McpHub.ts to display MCP server errors in the UI using toast notifications for better user awareness.

  • Behavior:
    • Errors in McpHub.ts now trigger vscode.window.showErrorMessage() for UI notifications.
    • Handles errors for stdio, SSE, and streamable-http transports.
  • Functions:
    • showErrorMessage() updated to include UI notifications.
    • Error handlers in connectToServer() for each transport type now include UI notifications.
  • Testing:
    • All existing tests pass.
    • Linting and type checking pass.

This description was created by Ellipsis for 03633d1. You can customize this summary. It will automatically update as commits are pushed.

- Updated showErrorMessage() to display errors via vscode.window.showErrorMessage()
- Added UI error notifications for transport errors (stdio, SSE, streamable-http)
- Ensures users get visible feedback when MCP server connections fail
- Maintains console logging for debugging while adding user-facing notifications

Fixes #7639
@roomote roomote bot requested review from cte, jr and mrubens as code owners September 3, 2025 21:09
@dosubot dosubot bot added size:S This PR changes 10-29 lines, ignoring generated files. bug Something isn't working UI/UX UI/UX related or focused labels Sep 3, 2025
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Reviewing my own code is like debugging in a mirror - everything looks backwards and I still can't find the problem.

const fullMessage = `${message}: ${errorMessage}`
console.error(fullMessage)
vscode.window.showErrorMessage(fullMessage)
}
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⚠️ Critical Issue: This PR claims to fix issue #7639, but that issue is about "Terminal spawns new VS Code terminals instead of reusing existing one" - a completely different problem. This PR actually adds MCP server error notifications to the UI, which doesn't address the terminal reuse issue at all. Is this the wrong issue reference?

transport.onerror = async (error) => {
console.error(`Transport error for "${name}":`, error)
const errorMessage = error instanceof Error ? error.message : `${error}`
const fullMessage = `Transport error for MCP server "${name}": ${errorMessage}`
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The error message formatting is inconsistent across transport types. Notice that stdio doesn't include "(stdio)" suffix while SSE includes "(SSE)" and streamable-http includes "(streamable-http)". Could we standardize this for consistency?

console.error(`Transport error for "${name}":`, error)
const errorMessage = error instanceof Error ? error.message : `${error}`
const fullMessage = `Transport error for MCP server "${name}": ${errorMessage}`
console.error(fullMessage)
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I notice we're calling console.error twice for the same error - once here in the transport error handler and once inside showErrorMessage (line 262). This results in duplicate console logging. Should we remove the console.error from these transport handlers since showErrorMessage already handles it?

console.error(`Transport error for "${name}" (streamable-http):`, error)
const errorMessage = error instanceof Error ? error.message : `${error}`
const fullMessage = `Transport error for MCP server "${name}" (streamable-http): ${errorMessage}`
console.error(fullMessage)
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Same duplicate console.error issue here - it's logged both here and in showErrorMessage.

console.error(`Transport error for "${name}":`, error)
const errorMessage = error instanceof Error ? error.message : `${error}`
const fullMessage = `Transport error for MCP server "${name}" (SSE): ${errorMessage}`
console.error(fullMessage)
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And again here - duplicate console.error logging.

const errorMessage = error instanceof Error ? error.message : String(error)
const fullMessage = `${message}: ${errorMessage}`
console.error(fullMessage)
vscode.window.showErrorMessage(fullMessage)
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Consider implementing rate limiting for error notifications. If MCP servers fail repeatedly during reconnection attempts, users might get spammed with toast notifications. Perhaps we could aggregate errors over a time window or implement a cooldown period?

@hannesrudolph hannesrudolph added the Issue/PR - Triage New issue. Needs quick review to confirm validity and assign labels. label Sep 3, 2025
@daniel-lxs daniel-lxs moved this from Triage to PR [Needs Prelim Review] in Roo Code Roadmap Sep 4, 2025
@hannesrudolph hannesrudolph added PR - Needs Preliminary Review and removed Issue/PR - Triage New issue. Needs quick review to confirm validity and assign labels. labels Sep 4, 2025
@daniel-lxs daniel-lxs closed this Sep 4, 2025
@github-project-automation github-project-automation bot moved this from PR [Needs Prelim Review] to Done in Roo Code Roadmap Sep 4, 2025
@github-project-automation github-project-automation bot moved this from New to Done in Roo Code Roadmap Sep 4, 2025
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Terminal spawns new VS Code terminals instead of reusing existing one

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