Fix: Add missing MCP SDK discovery attributes to PivotTable tool

[Copilot]

Summary

excel_pivottable tool was invisible to LLMs despite complete implementation. Missing [McpServerToolType] class attribute and explicit tool name prevented MCP SDK's WithToolsFromAssembly() discovery.

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update
• 🔧 Maintenance (dependency updates, code cleanup, etc.)

Related Issues

Closes #[issue number per problem statement]

Changes Made

ExcelPivotTableTool.cs (2 lines):

• Added [McpServerToolType] to class - required for SDK assembly scanning
• Added explicit Name = "excel_pivottable" to [McpServerTool] attribute

ToolDiscoveryTests.cs (new file, 24 tests):

• Verifies all 11 tools have [McpServerToolType] class attribute
• Verifies all 11 tools have [McpServerTool(Name = "...")] with correct naming convention
• Prevents regression

Pattern comparison:

// ❌ Before (not discoverable)
public static partial class ExcelPivotTableTool
{
    [McpServerTool]
    public static async Task<string> ExcelPivotTable(...)

// ✅ After (discoverable, matches all other tools)
[McpServerToolType]
public static partial class ExcelPivotTableTool
{
    [McpServerTool(Name = "excel_pivottable")]
    public static async Task<string> ExcelPivotTable(...)

Testing Performed

• Build produces zero warnings
• All 24 unit tests pass (ToolDiscoveryTests)
• Smoke test compiles and references tool correctly
• Verified pattern matches all 10 other working MCP tools

Test Commands

# Unit tests (no Excel required)
dotnet test --filter "Category=Unit&Feature=ToolDiscovery"

# Smoke test (requires Excel)
dotnet test --filter "FullyQualifiedName~McpServerSmokeTests.SmokeTest_AllTools_LlmWorkflow"

Screenshots (if applicable)

N/A - attribute-only fix with no UI changes

Core Commands Coverage Checklist ⚠️

Does this PR add or modify Core Commands methods? [x] No

Core implementation already existed and was complete. Only MCP SDK discovery attributes were missing.

Checklist

• Code follows project style guidelines
• Self-review of code completed
• Code builds with zero warnings
• Appropriate error handling added
• Updated help text (if adding new commands)
• Updated README.md (if needed)
• Follows Excel COM best practices from copilot-instructions.md
• Uses ExcelHelper.WithExcel() for Excel operations
• Properly handles 1-based Excel indexing
• Escapes user input with .EscapeMarkup()
• Returns consistent exit codes (0 = success, 1+ = error)

Additional Notes

Documentation already listed excel_pivottable as tool #6 of 11 - only discovery mechanism was broken. Zero functional changes to PivotTable implementation itself.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[BUG] LLMs cannot find the PivotTable functionality in the MCP Server</issue_title>
<issue_description>They only see:

excel_batch
excel_connection
excel_datamodel
excel_file
excel_namedrange
excel_powerquery
excel_querytable
excel_range
excel_table
excel_vba
excel_worksheet</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [BUG] LLMs cannot find the PivotTable functionality in the MCP Server #155

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[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None