.NET: Declarative Agents

[markwallace-microsoft]

Motivation and Context

• Update declarative agent samples
• Add the Microsoft.Agents.AI.Declarative project

Description

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[Copilot]

Pull request overview

This PR introduces declarative agent support to the .NET Agent Framework by adding the Microsoft.Agents.AI.Declarative project and updating sample YAML configuration files.

Key changes:

• Added new Microsoft.Agents.AI.Declarative project with factory pattern for creating agents from YAML definitions
• Implemented extension methods for converting between declarative object model types and runtime AI types
• Fixed spelling errors in agent instruction texts across multiple YAML sample files

Reviewed changes

Copilot reviewed 28 out of 28 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
Microsoft.Agents.AI.Declarative.csproj	New project file defining dependencies and configuration for the declarative agents library
agent-framework-dotnet.slnx	Added the new declarative project to the solution
AgentFactory.cs	Base abstract factory class for creating AI agents from declarative definitions
AggregatorAgentFactory.cs	Composite factory that aggregates multiple agent factories
ChatClientAgentFactory.cs	Concrete factory implementation for creating ChatClient-based agents
AgentBotElementYaml.cs	Helper methods for deserializing YAML to agent definitions
YamlAgentFactoryExtensions.cs	Extension methods to create agents from YAML strings
PromptAgentExtensions.cs	Extensions for converting GptComponentMetadata to ChatOptions and tools
Extension files (RecordData*, PropertyInfo*, StringExpression*, ModelOptions*, Tool*)	Type conversion extensions between declarative and runtime types
YAML sample files	Updated instructions to fix grammar errors and standardized property names from kind to type