Migrate Search tools to new tool design

[alzimmermsft]

What does this PR do?

Migrates Search tools to new design where Register and Bind options are based on Option attributes.

GitHub issue number?

[Link to the GitHub issue this PR addresses]

Pre-merge Checklist

• Required for All PRs
  • Read contribution guidelines
  • PR title clearly describes the change
  • Commit history is clean with descriptive messages (cleanup guide)
  • Added comprehensive tests for new/modified functionality
  • Created a changelog entry if the change falls among the following: new feature, bug fix, UI/UX update, breaking change, or updated dependencies. Follow the changelog entry guide
• For MCP tool changes:
  • One tool per PR: This PR adds or modifies only one MCP tool for faster review cycles
  • Updated servers/Azure.Mcp.Server/README.md and/or servers/Fabric.Mcp.Server/README.md documentation
  • Validate README.md changes running the script ./eng/scripts/Process-PackageReadMe.ps1. See Package README
  • For new or modified tool descriptions, ran ToolDescriptionEvaluator and obtained a score of 0.4 or more and a top 3 ranking for all related test prompts
  • For tools with new names, including new tools or renamed tools, update consolidated-tools.json
  • For renamed tools, follow the Tool Rename Checklist and tag the PR with the breaking-change label
  • For new tools associated with Azure services or publicly available tools/APIs/products, add URL to documentation in the PR description
• Extra steps for Azure MCP Server tool changes:
  • Updated command list in servers/Azure.Mcp.Server/docs/azmcp-commands.md
  • Ran ./eng/scripts/Update-AzCommandsMetadata.ps1 to update tool metadata in azmcp-commands.md (required for CI)
  • Updated test prompts in servers/Azure.Mcp.Server/docs/e2eTestPrompts.md
  • 👉 For Community (non-Microsoft team member) PRs:
    • Security review: Reviewed code for security vulnerabilities, malicious code, or suspicious activities before running tests (crypto mining, spam, data exfiltration, etc.)
    • Manual tests run: added comment /azp run mcp - pullrequest - live to run Live Test Pipeline

[Copilot]

Pull request overview

This PR migrates the Azure Search toolset commands from explicit RegisterOptions/BindOptions(ParseResult) patterns to the newer attribute-based options model (Options POCO + [Option]/[OptionContainer]), aligning Search commands with the newer command base classes and reducing direct System.CommandLine usage in the toolset.

Changes:

• Converted Search commands to the new AuthenticatedCommand<TOptions, TResult> / SubscriptionCommand<TOptions, TResult> style with Options POCO binding.
• Replaced legacy option definition classes/base option types with [Option]-attributed options and a new SearchOptionDescriptions constants holder.
• Simplified toolset dependencies (e.g., removed explicit System.CommandLine package reference) and adjusted tests/service construction accordingly.

Reviewed changes

Copilot reviewed 26 out of 26 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tools/Azure.Mcp.Tools.Search/tests/Azure.Mcp.Tools.Search.Tests/Service/ServiceListCommandTests.cs	Updates test base class to match new subscription command shape.
tools/Azure.Mcp.Tools.Search/tests/Azure.Mcp.Tools.Search.Tests/Service/SearchServiceTests.cs	Updates service instantiation after constructor signature change.
tools/Azure.Mcp.Tools.Search/src/Services/SearchService.cs	Removes logger dependency and updates usings for System.Text.Json.
tools/Azure.Mcp.Tools.Search/src/Services/ISearchService.cs	Adds System.Text.Json import for JsonElement return types.
tools/Azure.Mcp.Tools.Search/src/Options/Service/ServiceListOptions.cs	Converts subscription options to [Option] attributes + ISubscriptionOption.
tools/Azure.Mcp.Tools.Search/src/Options/SearchOptionDescriptions.cs	Adds centralized option description constants for Search options.
tools/Azure.Mcp.Tools.Search/src/Options/SearchOptionDefinitions.cs	Removes legacy System.CommandLine-based option definitions.
tools/Azure.Mcp.Tools.Search/src/Options/Knowledge/KnowledgeSourceGetOptions.cs	Converts options to [Option] attribute model.
tools/Azure.Mcp.Tools.Search/src/Options/Knowledge/KnowledgeBaseRetrieveOptions.cs	Converts options to [Option] attribute model (query/messages/service/retry).
tools/Azure.Mcp.Tools.Search/src/Options/Knowledge/KnowledgeBaseGetOptions.cs	Converts options to [Option] attribute model.
tools/Azure.Mcp.Tools.Search/src/Options/Index/IndexQueryOptions.cs	Converts options to [Option] attribute model.
tools/Azure.Mcp.Tools.Search/src/Options/Index/IndexGetOptions.cs	Converts options to [Option] attribute model.
tools/Azure.Mcp.Tools.Search/src/Options/Index/BaseIndexOptions.cs	Removes obsolete base options type.
tools/Azure.Mcp.Tools.Search/src/Options/BaseSearchOptions.cs	Removes obsolete base options type.
tools/Azure.Mcp.Tools.Search/src/Models/IndexInfo.cs	Removes explicit JSON property annotations (rely on serializer naming policy).
tools/Azure.Mcp.Tools.Search/src/Models/FieldInfo.cs	Removes explicit JSON property annotations (rely on serializer naming policy).
tools/Azure.Mcp.Tools.Search/src/GlobalUsings.cs	Removes global usings no longer needed after migration.
tools/Azure.Mcp.Tools.Search/src/Commands/Service/ServiceListCommand.cs	Migrates to SubscriptionCommand<TOptions, TResult> and options binding model.
tools/Azure.Mcp.Tools.Search/src/Commands/SearchJsonContext.cs	Simplifies source-gen context declaration.
tools/Azure.Mcp.Tools.Search/src/Commands/Knowledge/KnowledgeSourceGetCommand.cs	Migrates to AuthenticatedCommand<TOptions, TResult> + options binding model.
tools/Azure.Mcp.Tools.Search/src/Commands/Knowledge/KnowledgeBaseRetrieveCommand.cs	Migrates to AuthenticatedCommand<TOptions, TResult> and moves validation into ValidateOptions.
tools/Azure.Mcp.Tools.Search/src/Commands/Knowledge/KnowledgeBaseGetCommand.cs	Migrates to AuthenticatedCommand<TOptions, TResult> + options binding model.
tools/Azure.Mcp.Tools.Search/src/Commands/Index/IndexQueryCommand.cs	Migrates to AuthenticatedCommand<TOptions, TResult> and updates result type.
tools/Azure.Mcp.Tools.Search/src/Commands/Index/IndexGetCommand.cs	Migrates to AuthenticatedCommand<TOptions, TResult> + options binding model.
tools/Azure.Mcp.Tools.Search/src/Azure.Mcp.Tools.Search.csproj	Updates core ProjectReference path and removes System.CommandLine PackageReference.
servers/Azure.Mcp.Server/changelog-entries/1782416793886.yaml	Adds changelog entry indicating breaking changes for Search tools.

[jongio]

Clean migration that follows the pattern established by the ACR, StorageSync, and Monitor migrations. One minor nit below.

Note: the existing Copilot bot comment about options.Messages.Index() not compiling is incorrect. Enumerable.Index() is available in .NET 9+ and the repo targets net10.0, so it compiles fine (CI confirms).

[jongio]

Nit: all other options classes in this PR are public sealed class (consistent with the StorageSync migration pattern). This one is public class without sealed. Likely just an oversight.