[Remote] Live tests for HTTP accidentally test stdio mode

[vukelich]

Step that says it's testing HTTP transport:

mcp/eng/pipelines/templates/jobs/live-test.yml

Lines 93 to 110 in b9f596c

	- task: AzurePowershell@5
	displayName: "Run tests (http) - az pwsh"
	env:
	SYSTEM_ACCESSTOKEN: $(System.AccessToken)
	AZURE_MCP_COLLECT_TELEMETRY: 'false'
	inputs:
	azureSubscription: azure-sdk-tests-public
	azurePowerShellVersion: 'LatestVersion'
	scriptType: InlineScript
	Inline: |
	./eng/scripts/Test-Code.ps1 `
	-TestType 'Live' `
	-Path $(PathToTest) `
	-TestResultsPath '$(Build.ArtifactStagingDirectory)/testResults'
	exit $LastExitCode
	pwsh: true
	workingDirectory: $(Build.SourcesDirectory)

The step needs to assign a value to the MCP_TEST_TRANSPORT environment variable as per McpTestUtilities.CreateMcpClientAsync()

mcp/core/Microsoft.Mcp.Core/tests/Microsoft.Mcp.Tests/Client/Helpers/McpTestUtilities.cs

Lines 65 to 68 in b9f596c

	bool useHttp = string.Equals(
	Environment.GetEnvironmentVariable("MCP_TEST_TRANSPORT"),
	"http",
	StringComparison.OrdinalIgnoreCase);

Stdio setup that prints "MCP client initialized successfully":

mcp/core/Microsoft.Mcp.Core/tests/Microsoft.Mcp.Tests/Client/Helpers/McpTestUtilities.cs

Line 108 in b9f596c

output?.WriteLine("MCP client initialized successfully");

http setup that prints "HTTP test client initialized at {serverUrl}":

mcp/core/Microsoft.Mcp.Core/tests/Microsoft.Mcp.Tests/Client/Helpers/McpTestUtilities.cs

Line 92 in b9f596c

output?.WriteLine($"HTTP test client initialized at {serverUrl}");

Proof that the http job is spitting out setup output from LiveServerFixture along the branch that uses stdio, i.e., MCP client initialized successfully:
https://dev.azure.com/azure-sdk/internal/_build/results?buildId=6694418&view=logs&j=5159808d-2ee1-5ad5-3b4c-ac54c933eeca&t=ede6e3df-33c6-5265-3117-059cd58c238d&l=34

[github-actions]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc Vinay Gera (@g2vinay) JasonYeMSFT (@JasonYeMSFT) @microsoft/azure-mcp Srikanta (@srnagar) Steven Vukelich (@vukelich).

[github-actions]

Triage Summary

Classification: bug — The HTTP live test pipeline step is missing the MCP_TEST_TRANSPORT environment variable assignment, causing it to silently fall back to stdio mode. This means HTTP transport is not actually being tested despite the step's intent.

Priority: High — This is a test correctness issue for Remote MCP: the HTTP transport path is completely untested in CI, masking any HTTP-specific regressions.

Issue Type: Bug

Labels added: bug

Owner recommendation: @chidozieononiwu and @JasonYeMSFT are already assigned and are the right owners given the remote-mcp context. The fix is straightforward: add MCP_TEST_TRANSPORT: http (or equivalent) to the live-test pipeline step at eng/pipelines/templates/jobs/live-test.yml lines 93–110.

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