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Roger Barreto b12109b7e4 .NET: Bump MEAI to 10.5.1 and add Foundry per-call x-client header support (#5652)
* Bump MEAI to 10.5.1 and add per-call x-client header support

Replaces the brittle UserAgentResponsesClient subclass with a clean
per-call x-client-* header pipeline built on the new Microsoft.Extensions.AI
10.5.1 OpenAIRequestPolicies hook.

Public surface (Microsoft.Agents.AI.Foundry, [Experimental(MAAI001)]):
* chatOptions.WithClientHeader(name, value) and .WithClientHeaders(IEnumerable)
  validate the x-client- prefix (case-insensitive), apply all-or-nothing on
  bulk, and throw InvalidOperationException on foreign-typed slot collision
* myAgent.AsBuilder().UseClientHeaders().Build() opts a customer-built agent
  into the pipeline; idempotent via agent.GetService<ClientHeadersAgent>()
* Foundry-built agents (FoundryAgent.Create*) pre-wire automatically

Internals:
* ClientHeadersAgent decorator snapshots the dict at scope-push time so
  concurrent runs sharing a ChatOptions reference do not leak headers
* ClientHeadersScope is an AsyncLocal<IReadOnlyDictionary<string,string>?>
  with LIFO push/dispose semantics
* ClientHeadersPolicy singleton stamps headers via Headers.Set so per-call
  values overwrite any same-name header from earlier policies and so
  duplicate registration is value-stable
* OpenAIRequestPoliciesReflection dedups against MEAI's private _entries
  field and falls back to AddPolicy on any reflection failure; a CI test
  asserts the field shape on every MEAI bump

Hosting cleanup:
* Deleted UserAgentResponsesClient and its dummy throwing pipeline
* HostedAgentUserAgentPolicy is now registered via OpenAIRequestPolicies
  in FoundryHostingExtensions.TryApplyUserAgent

Tests:
* 19 new unit tests in ClientHeadersExtensionsTests.cs covering validation,
  AsyncLocal isolation, snapshot semantics, end-to-end wire stamping, and
  shared-chat-client dedup
* Updated OpenTelemetryAgentTests for MEAI 10.5.1 changes to web_search
  serialization and the reduced tool definition payload when sensitive
  data capture is disabled

Microsoft.Extensions.Compliance.Abstractions stays at 10.5.0 because no
10.5.1 release exists on nuget.org.

* Address PR review: pre-wire AsAIAgent path and dedup TryApplyUserAgent

* FoundryAgent: extract WireClientHeaders helper and call it from the
  internal (AIProjectClient, ChatClientAgent) constructor used by
  AzureAIProjectChatClientExtensions.AsAIAgent so those Foundry-built
  agents also pre-wire the x-client header pipeline.
* Foundry.Hosting TryApplyUserAgent: dedup HostedAgentUserAgentPolicy
  registration per OpenAIRequestPolicies instance via
  ConditionalWeakTable so per-request resolution does not grow the
  policy list unboundedly on singleton agents.

* Add tests covering AsAIAgent pre-wire and TryApplyUserAgent dedup

Backs the PR review fixes from a4c8f91 with regression tests:
* ClientHeadersExtensionsTests: AsAIAgent_FoundryAgent_HasPreWiredClientHeadersAgent
  asserts the FoundryAgent built via AzureAIProjectChatClientExtensions.AsAIAgent
  contains a ClientHeadersAgent in its delegating chain (catches future
  regressions of the bypass).
* ClientHeadersExtensionsTests: FoundryAgent_PublicConstructor_HasPreWiredClientHeadersAgent
  covers the public constructor path the same way.
* ClientHeadersExtensionsTests: UseClientHeaders_RepeatedRegistrations_OnSameChatClient_OnlyRegistersOnce
  invokes UseClientHeaders 25 times on a shared chat client and asserts via
  reflection that OpenAIRequestPolicies._entries length is exactly 1.
* HostedTryApplyUserAgentDedupTests: two tests asserting
  FoundryHostingExtensions.TryApplyUserAgent stays at one entry per
  OpenAIRequestPolicies instance after 50 calls on the same agent and across
  distinct agents on different chat clients.

* Move tests next to their SUT

Removes the dedicated HostedTryApplyUserAgentDedupTests.cs test class.
Tests are co-located with the SUT they exercise:

* FoundryAgentTests.cs gains the Constructor_PreWiresClientHeadersAgent
  and Constructor_FromAsAIAgentExtension_PreWiresClientHeadersAgent
  cases, since FoundryAgent is the SUT for the pre-wire behavior.
* HostedOutboundUserAgentTests.cs gains the two TryApplyUserAgent dedup
  cases, since FoundryHostingExtensions.TryApplyUserAgent is the SUT
  it already covers.
* ClientHeadersExtensionsTests.cs keeps only the
  UseClientHeaders_RepeatedRegistrations_OnSameChatClient_OnlyRegistersOnce
  case, which exercises the public ClientHeadersExtensions surface.

* Remove redundant WithCancellation on inner streaming call

ct is already passed to InnerAgent.RunStreamingAsync, so
.WithCancellation(ct) on the resulting IAsyncEnumerable is a no-op.
Caught by Sergey on PR review.

* Address PR review: surface downstream MEAI experimental ID

* Add AIOpenAIRequestPolicies = MEAIExperiments alias to
  DiagnosticIds.Experiments (matches the existing AIResponseContinuations,
  AIMcpServers, AIFunctionApprovals pattern).
* Mark public ClientHeadersExtensions with [Experimental(AIOpenAIRequestPolicies)]
  instead of AgentsAIExperiments. Consumers now see the MEAI001 warning,
  surfacing the dependency on MEAI's experimental OpenAIRequestPolicies hook.
* Mark internal OpenAIRequestPoliciesReflection with the same alias to
  suppress warnings at the source rather than via project-wide NoWarn.
* Remove MEAI001 from Foundry csproj NoWarn (kept on Foundry.Hosting where
  pre-PR usages remain).
* Clarify ClientHeadersScope XML doc: AsyncLocal flows values forward but
  does NOT auto-restore on method return; explicit using/Dispose is what
  gives stack-style LIFO semantics.
b12109b7e4 ยท 2026-05-06 14:43:08 +00:00
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