.NET: Migrate 01-get-started samples to Foundry as canonical default

[alliscode]

This pull request updates the canonical "01-get-started" .NET samples to use Microsoft Foundry as the default AI provider instead of Azure OpenAI. It replaces all references to Azure OpenAI with Microsoft Foundry, updates environment variables, and adjusts project dependencies accordingly. The documentation is also revised to reflect these changes.

Provider migration and environment variables:

• All samples in 01-get-started now use FoundryAgent from Microsoft.Agents.AI.Foundry instead of AzureOpenAIClient from Microsoft.Agents.AI.OpenAI. [1] [2] [3] [4] [5]
• Environment variables have been updated from AZURE_OPENAI_ENDPOINT and AZURE_OPENAI_DEPLOYMENT_NAME to FOUNDRY_PROJECT_ENDPOINT and FOUNDRY_MODEL throughout code, sample verification, and documentation. [1] [2] [3] [4] [5] [6]

Project and package dependency updates:

• All sample .csproj files now reference Microsoft.Agents.AI.Foundry and Microsoft.Extensions.AI.Abstractions instead of OpenAI-specific packages. [1] [2]

Sample code and logic changes:

• Sample logic is updated to instantiate and use FoundryAgent, including for advanced scenarios like memory and Azure Functions hosting. [1] [2] [3]
• Sample descriptions and comments are revised to reference Foundry and the new environment variables. [1] [2] [3]

Documentation updates:

• AGENTS.md is updated to show Foundry as the default provider, including code snippets and environment variable descriptions. [1] [2]

[Copilot]

Pull request overview

Migrates the canonical .NET “01-get-started” samples to use Microsoft Foundry (Foundry Responses API) as the default backend, updating code, environment variables, and project references so the onboarding path aligns with the Foundry-first direction of the Agent Framework samples.

Changes:

• Switch 01-get-started samples from Azure OpenAI (AzureOpenAIClient) to Foundry (FoundryAgent) and rename env vars to FOUNDRY_PROJECT_ENDPOINT / FOUNDRY_MODEL.
• Update sample project dependencies to reference Microsoft.Agents.AI.Foundry and remove Azure OpenAI-specific packages/references.
• Refresh dotnet/samples/AGENTS.md to document Foundry as the default provider and point readers to other provider samples.

Show a summary per file

File	Description
dotnet/samples/AGENTS.md	Updates documentation to state Foundry is the default backend for canonical samples and updates the example/env vars accordingly.
dotnet/samples/01-get-started/01_hello_agent/Program.cs	Migrates the “hello agent” sample to instantiate and run a FoundryAgent.
dotnet/samples/01-get-started/01_hello_agent/01_hello_agent.csproj	Removes Azure OpenAI deps and references the Foundry project.
dotnet/samples/01-get-started/02_add_tools/Program.cs	Migrates the tools sample to use FoundryAgent and keeps function tool wiring.
dotnet/samples/01-get-started/02_add_tools/02_add_tools.csproj	Removes Azure OpenAI deps and references the Foundry project.
dotnet/samples/01-get-started/03_multi_turn/Program.cs	Migrates multi-turn conversation sample to FoundryAgent with Foundry env vars.
dotnet/samples/01-get-started/03_multi_turn/03_multi_turn.csproj	Removes Azure OpenAI deps and references the Foundry project.
dotnet/samples/01-get-started/04_memory/Program.cs	Migrates memory sample to Foundry and updates how the IChatClient is obtained and passed into the memory provider.
dotnet/samples/01-get-started/04_memory/04_memory.csproj	Removes Azure OpenAI deps and references the Foundry project; swaps to MEAI abstractions.
dotnet/samples/01-get-started/06_host_your_agent/Program.cs	Migrates Azure Functions hosting sample to use FoundryAgent and Foundry env vars.
dotnet/samples/01-get-started/06_host_your_agent/06_host_your_agent.csproj	Removes Azure OpenAI deps and references the Foundry project.

Copilot's findings

• Files reviewed: 11/11 changed files
• Comments generated: 1

[github-actions]

Automated Code Review

Reviewers: 5 | Confidence: 92%

✓ Correctness

This PR cleanly migrates the 01-get-started samples from Azure OpenAI to Microsoft Foundry. The API usage is correct: FoundryAgent constructor signatures match, GetService() delegation chain works properly, and transitive dependencies (Microsoft.Extensions.AI for AIFunctionFactory) are satisfied through the Foundry project reference. The only issue is a missing using directive in the AGENTS.md documentation snippet.

✓ Security Reliability

This PR migrates 01-get-started samples from Azure OpenAI to Microsoft Foundry. The changes are straightforward provider swaps with no security or reliability regressions. All samples properly validate required environment variables, include appropriate warnings about DefaultAzureCredential in production, hardcode no secrets, and the FoundryAgent constructor validates all parameters (null/whitespace checks on model, instructions, endpoint, credential). The 04_memory sample correctly handles the nullable return from GetService() with an explicit null check and throw.

✓ Test Coverage

The PR migrates 01-get-started samples from Azure OpenAI to Microsoft Foundry but does not update the sample verification harness (dotnet/eng/verify-samples/GetStartedSamples.cs). That file still declares RequiredEnvironmentVariables as ['AZURE_OPENAI_ENDPOINT'] and OptionalEnvironmentVariables as ['AZURE_OPENAI_DEPLOYMENT_NAME'] for samples 01–04 and 06, but the samples now require FOUNDRY_PROJECT_ENDPOINT and optionally FOUNDRY_MODEL. This means the harness will incorrectly skip these samples when only Foundry env vars are set, or attempt to run them (then fail at startup) when only the old OpenAI env vars are set.

✓ Failure Modes

This PR cleanly migrates 01-get-started samples from Azure OpenAI to Microsoft Foundry. The most complex change (04_memory) creates a FoundryAgent to bootstrap the IChatClient, extracts it via GetService(), and wraps it in a new ChatClientAgent with different options. This pattern is safe: the null check properly handles the failure case, the middleware deduplication in WithDefaultAgentMiddleware prevents double-decoration, and the baseAgent's instructions don't propagate through the raw IChatClient. All other samples are straightforward constructor swaps with no new failure paths introduced.

✓ Design Approach

I found one non-blocking design inconsistency in the 04_memory sample. The PR updates the canonical 01-get-started story to say these samples use Foundry via FoundryAgent or AIProjectClient.AsAIAgent(), but this sample still drops down to a generic IChatClient.AsAIAgent(...) path after constructing a temporary FoundryAgent. The repo already provides an AIProjectClient.AsAIAgent(ChatClientAgentOptions) overload for exactly this kind of customized setup, so the current approach weakens the new canonical provider story without adding capability.

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Automated review by alliscode's agents

[github-actions]

Automated Code Review

Reviewers: 5 | Confidence: 91% | Result: All clear

Reviewed: Correctness, Security Reliability, Test Coverage, Failure Modes, Design Approach

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Automated review by alliscode's agents