[jongalloway]

Why

The MCP 2.x migration is already present, but the full suite still had 35 failures and tool command tests could modify the checked-in tool manifest or the user's global installations. This restores a green suite while retaining the existing MCP SDK 2.3.0 packages and native/legacy protocol contracts.

Approach

• Align Microsoft.Build.Utilities.Core with Microsoft.Build 18.9.6 so .NET 10 runtime assemblies are available, and explicitly supply the NuGet.Frameworks version required by MSBuild property functions.
• Correct fixtures that assumed SDK-defaulted properties were unset. Separately cover missing-framework validation for non-SDK projects and evaluation errors for SDK projects.
• Serialize workspace snapshot tests through the existing process-wide-state collection.
• Add an internal, per-instance executor override so tool command tests record commands instead of changing real installations. Strengthen install/update/uninstall argument assertions and cover interception for both local and global operations. Other commands and production execution remain unchanged.
• Document test isolation and runtime dependency requirements. The source-controlled tool manifest has no diff.

Verification

• Release server build: passed with zero warnings or errors.
• Full Release suite: 1,615 passed, 46 expected skips, zero failures (baseline: 1,573 passed, 35 failed, 46 skipped).
• Focused repaired tests and SDK compatibility matrix: 607 passed, two interactive skips.
• Real-stdio scenario suite: all 14 passed.
• Isolated local-tool manifest/install/restore/list release scenario: passed.

Fixes: #488

[Copilot]

🟢 Approval recommended

No active review issues are identified for the fixture repairs and tool-command test isolation changes.

No open issues 🎉

What changed in this PR

This PR addresses #488 by repairing test fixtures and isolating tool-command tests while retaining MCP SDK 2.3.0 and the existing native and legacy protocol contracts.

Changes:

• Align MSBuild runtime dependencies and correct project-analysis fixtures for SDK-evaluated properties.
• Record tool commands through a per-instance executor override, with stronger argument assertions and local/global interception coverage.
• Serialize workspace snapshot tests and document test isolation and runtime requirements.

File	Description
DotNetMcp/​Tools/​Cli/​DotNetCliTools.Core.cs	Adds an internal executor override shared by normal and concurrency-controlled execution.
DotNetMcp/​DotNetMcp.csproj	Aligns MSBuild packages and explicitly references NuGet.Frameworks.
DotNetMcp.Tests/​Tools/​EdgeCaseAndIntegrationTests.cs	Enables tool-command recording to avoid real tool changes.
DotNetMcp.Tests/​Tools/​DotNetCliToolsTests.cs	Records tool commands and strengthens argument assertions.
DotNetMcp.Tests/​Tools/​DotNetCliToolsConsolidatedToolTests.cs	Adds local/global interception coverage and command assertions.
DotNetMcp.Tests/​SdkIntegration/​ProjectAnalysisHelperTests.cs	Corrects unset-property fixtures and separates evaluation-error coverage from validation.
DotNetMcp.Tests/​Resources/​WorkspaceSnapshotResourceTests.cs	Uses the nonparallel process-wide-state collection.
DotNetMcp.Tests/​Infrastructure/​MachineReadableCommandAssertions.cs	Adds a recorder for tool commands while preserving execution of other commands.
doc/​testing.md	Documents compatibility, isolation, and runtime dependency requirements.

_{Review effort: Balanced}