.NET: Update FoundryAgent to address HostedAgents strict URL routing#5677
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rogerbarreto merged 5 commits intomicrosoft:mainfrom May 8, 2026
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…ectly 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 microsoft#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 microsoft#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.
…rosoft.Agents.AI.Foundry to preview Required to fix the NU1109 downgrade chain that broke CI on the agent-endpoint constructor rewire (microsoft#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.
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Summary
Workaround for Azure/azure-sdk-for-net#59011: the experimental
FoundryAgent(Uri agentEndpoint, AuthenticationTokenProvider, ...)constructor was producing a project-level URL that the Foundry service rejects with HTTP 400 for hosted agents.This PR rewires the agent-endpoint constructor to build a per-agent
ProjectOpenAIClientdirectly so the outbound URL matches the per-agent shape the service expects. TheMicrosoft.Agents.AI.Foundrypackage flips back to preview while we depend onAzure.AI.Projects 2.1.0-beta.1.FoundryAgentis[Experimental(OPENAI001)]. No GA surface touched.