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Roger Barreto eb709d8fc9 .NET: Update FoundryAgent to address HostedAgents strict URL routing (#5677)
* .NET: Foundry agent-endpoint constructor uses ProjectOpenAIClient directly to fix hosted-agent URL routing

Fixes the experimental FoundryAgent(Uri agentEndpoint, AuthenticationTokenProvider, ...)
constructor so it actually works against Foundry hosted agents.

The previous implementation routed through AzureAIProjectChatClient, which
internally called aiProjectClient.GetProjectOpenAIClient().GetProjectResponsesClientForAgent(...).
For an agent-endpoint URL of the canonical shape

  https://<host>/api/projects/<project>/agents/<agentName>/endpoint/protocols/openai

the chain produced

  POST https://<host>/api/projects/<project>/openai/v1/responses

(project-level path, no /agents/ segment). The Foundry service rejects this with
HTTP 400 "Hosted agents can only be called through the agent endpoint:
.../agents/<agentName>/endpoint/protocols/openai/responses".

The constructor also extracted the agent name via
agentEndpoint.Segments[^1].TrimEnd('/'), which returns "openai" (the last segment),
not the agent name.

What changed
- Public ctor signature: clientOptions parameter type changed from
  AIProjectClientOptions? to ProjectOpenAIClientOptions?. The constructor is
  fundamentally building a ProjectOpenAIClient; accepting AIProjectClientOptions
  was a leaky abstraction whose translation silently dropped any pipeline
  policies the caller added via AddPolicy(...). With the direct type, caller
  policies pass through to the per-agent traffic verbatim.
- Per-agent client construction: `new ProjectOpenAIClient(BearerTokenPolicy, ProjectOpenAIClientOptions)`
  with Endpoint and AgentName set, then `GetProjectResponsesClient().AsIChatClient()`.
  The SDK auto-appends ?api-version=v1 when AgentName is set.
- New private static ParseAgentEndpoint helper: single source of truth for both
  agent-name extraction and project-root derivation. Tolerates trailing slash,
  case variants on /agents/ and the suffix segment, strips query/fragment, and
  throws ArgumentException with paramName=nameof(agentEndpoint) for malformed input.
- Project-level client (used by CreateConversationSessionAsync) is built fresh
  from the derived project root with primitive properties copied
  (RetryPolicy/NetworkTimeout/Transport/UserAgentApplicationId) plus MEAI UA.
- New GetService<ProjectOpenAIClient>() entry alongside the existing
  GetService<AIProjectClient>() (the latter returns null in agent-endpoint mode
  since no AIProjectClient is constructed on that path).
- Endpoint and AgentName on caller-supplied ProjectOpenAIClientOptions are
  overridden by values derived from agentEndpoint.

Compatibility
- FoundryAgent is [Experimental(OPENAI001)]. No GA surface touched. The Foundry
  project does not maintain PublicAPI.*.txt baselines so there is no shipped
  baseline to update.
- The Microsoft.Agents.AI.Foundry csproj pins
  Azure.AI.Projects to VersionOverride 2.1.0-beta.1 (matching what the IT and
  hosting projects already use); the central pin in Directory.Packages.props
  stays at 2.0.0.
- WireClientHeaders from PR #5652 is invoked on the agent-endpoint path so
  per-call x-client-* headers behave identically across both ctors.

Tests
- 23 new unit tests in FoundryAgentTests.cs:
  - 12 for the agent-endpoint constructor (URL routing for non-streaming and
    streaming, conversations URL shape, MEAI UA stamping, caller-policy
    passthrough on the per-agent pipeline, Endpoint/AgentName override
    semantics, GetService matrix, ProjectOpenAIClient propagation,
    UserAgentApplicationId propagation, null-arg validation, ID/Name slug)
  - 9 for ParseAgentEndpoint (standard shape, trailing slash, casing,
    sovereign-cloud host without /api/projects/ literal prefix, special chars
    in agent name, query/fragment stripping, three negative cases)
  - 2 null-arg tests for the public ctor
- All 250 Microsoft.Agents.AI.Foundry.UnitTests pass (was 221 baseline plus
  29 from PR #5652 plus 23 new in this PR equals 273; pre-existing tests
  collapsed by the rebase merge keep the total at 250).
- All 225 Microsoft.Agents.AI.Foundry.Hosting.UnitTests pass; no behavioral
  change to the hosting layer.
- dotnet build clean across net8/9/10/netstandard2.0/net472 with
  TreatWarningsAsErrors=true.
- dotnet format --verify-no-changes clean for the touched src and test projects.

* .NET: Bump central Azure.AI.Projects pin to 2.1.0-beta.1 and flip Microsoft.Agents.AI.Foundry to preview

Required to fix the NU1109 downgrade chain that broke CI on the agent-endpoint
constructor rewire (#5677). Microsoft.Agents.AI.Foundry now depends on
ProjectOpenAIClientOptions.AgentName and the (AuthenticationPolicy, options)
constructor that only exist in Azure.AI.Projects 2.1.0-beta.1.

Changes:
* Directory.Packages.props: Azure.AI.Projects 2.0.0 -> 2.1.0-beta.1.
* Microsoft.Agents.AI.Foundry.csproj: drop IsReleased=true so the package ships
  as preview (matches the beta SDK we now depend on). Add a comment noting the
  flip is temporary and should revert once Azure.AI.Projects ships a stable
  2.1.0.
* Drop redundant VersionOverride="2.1.0-beta.1" from the 10 csprojs that had it
  as a workaround; the central pin now suffices.

Verified:
* dotnet build agent-framework-dotnet.slnx --warnaserror clean across all TFMs.
* Microsoft.Agents.AI.Foundry.UnitTests 250/250 pass.
* Microsoft.Agents.AI.Foundry.Hosting.UnitTests 211/211 pass.
* dotnet format --verify-no-changes clean for the touched src and test projects.
eb709d8fc9 ยท 2026-05-08 14:46:52 +00:00
History
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Getting started with Foundry Agents

These samples demonstrate how to use Microsoft Foundry with Agent Framework.

Quick start

The simplest way to create a Foundry agent is using the FoundryAgent type directly:

FoundryAgent agent = new(
    new Uri(endpoint),
    new AzureCliCredential(),
    model: "gpt-5.4-mini",
    instructions: "You are good at telling jokes.",
    name: "JokerAgent");

Console.WriteLine(await agent.RunAsync("Tell me a joke about a pirate."));

Or using the AIProjectClient.AsAIAgent(...) extensions:

AIProjectClient aiProjectClient = new(new Uri(endpoint), new DefaultAzureCredential());

FoundryAgent agent = aiProjectClient.AsAIAgent(
    model: deploymentName,
    instructions: "You are good at telling jokes.",
    name: "JokerAgent");

Prerequisites

  • .NET 10 SDK or later
  • Foundry project endpoint
  • Azure CLI installed and authenticated

Set:

$env:AZURE_AI_PROJECT_ENDPOINT="https://your-foundry-service.services.ai.azure.com/api/projects/your-foundry-project"
$env:AZURE_AI_MODEL_DEPLOYMENT_NAME="gpt-5.4-mini"

Some samples require extra tool-specific environment variables. See each sample for details.

Samples

Sample Description
FoundryAgent lifecycle Create a FoundryAgent directly with endpoint and credentials
Basics (Responses API) Create and run an agent using AsAIAgent extensions
Multi-turn conversation Multi-turn using sessions and response ID chaining
Multi-turn with server conversations Server-side conversations visible in Foundry UI
Using function tools Function tools
Function tools with approvals Human-in-the-loop approval
Structured output Structured output with JSON schema
Persisted conversations Persisting and resuming conversations
Observability OpenTelemetry observability
Dependency injection DI with a hosted service
Using MCP client as tools MCP client tools
Using images Image multi-modality
Agent as function tool Agent as a function tool for another
Middleware Multiple middleware layers
Plugins Plugins with dependency injection
Code interpreter Code interpreter tool
Computer use Computer use tool
File search File search tool
OpenAPI tools OpenAPI tools
Bing custom search Bing Custom Search tool
SharePoint SharePoint grounding tool
Microsoft Fabric Microsoft Fabric tool
Web search Web search tool
Memory search Memory search tool
Local MCP Local MCP client with HTTP transport
Code interpreter file download Download container files generated by code interpreter

Running the samples

cd dotnet/samples/02-agents/AgentsWithFoundry
dotnet run --project .\FoundryAgent_Step01