eavanvalkenburg
diff --git a/‎dotnet/src/Microsoft.Agents.AI.Foundry.Hosting/HostedAgentUserAgentPolicy.cs‎
Lines changed: 60 additions & 5 deletions b/‎dotnet/src/Microsoft.Agents.AI.Foundry.Hosting/HostedAgentUserAgentPolicy.cs‎
Lines changed: 60 additions & 5 deletions
diff --git a/‎…ry/AzureAIProjectChatClientExtensions.cs‎ ‎….AI.Foundry/AIProjectClientExtensions.cs‎dotnet/src/Microsoft.Agents.AI.Foundry/AzureAIProjectChatClientExtensions.cs renamed to dotnet/src/Microsoft.Agents.AI.Foundry/AIProjectClientExtensions.cs
Lines changed: 8 additions & 11 deletions b/‎…ry/AzureAIProjectChatClientExtensions.cs‎ ‎….AI.Foundry/AIProjectClientExtensions.cs‎dotnet/src/Microsoft.Agents.AI.Foundry/AzureAIProjectChatClientExtensions.cs renamed to dotnet/src/Microsoft.Agents.AI.Foundry/AIProjectClientExtensions.cs
Lines changed: 8 additions & 11 deletions
diff --git a/‎dotnet/src/Microsoft.Agents.AI.Foundry/AgentFrameworkUserAgentPolicy.cs‎
Lines changed: 88 additions & 0 deletions b/‎dotnet/src/Microsoft.Agents.AI.Foundry/AgentFrameworkUserAgentPolicy.cs‎
Lines changed: 88 additions & 0 deletions
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+using System;
 using System.ClientModel.Primitives;
 using System.Collections.Generic;
 using System.Reflection;
@@ -9,8 +10,11 @@
 namespace Microsoft.Agents.AI.Foundry.Hosting;
 
 /// <summary>
-/// Pipeline policy that appends the hosted-agent <c>User-Agent</c> segment
-/// (e.g. <c>"foundry-hosting/agent-framework-dotnet/{version}"</c>) to outgoing requests.
+/// Pipeline policy that emits the hosted-agent <c>User-Agent</c> segment
+/// (<c>"foundry-hosting/agent-framework-dotnet/{version}"</c>), matching Python's hosted
+/// contract (<c>foundry-hosting/agent-framework-python/{version}</c>, see
+/// <c>python/packages/core/agent_framework/_telemetry.py</c>: the hosted prefix is joined
+/// with the base agent-framework segment into a single combined User-Agent value).
 /// </summary>
 /// <remarks>
 /// <para>
@@ -19,6 +23,12 @@ namespace Microsoft.Agents.AI.Foundry.Hosting;
 /// is already present in the <c>User-Agent</c> header, the policy does not append it again.
 /// </para>
 /// <para>
+/// When a bare <c>agent-framework-dotnet/{version}</c> segment is already present (stamped by
+/// the framework-wide <c>AgentFrameworkUserAgentPolicy</c> registered by
+/// <c>FoundryChatClient</c>), this policy <em>replaces</em> that segment with the combined
+/// hosted form so the wire never carries both forms simultaneously, preserving Python parity.
+/// </para>
+/// <para>
 /// This policy is added at hosted-agent resolution time via the MEAI 10.5.1
 /// <see cref="OpenAIRequestPolicies"/> hook on the agent's underlying chat client. It is only
 /// registered when an agent is resolved by the Foundry hosting layer.
@@ -30,6 +40,12 @@ internal sealed class HostedAgentUserAgentPolicy : PipelinePolicy
 
     private static readonly string s_supplementValue = CreateSupplementValue();
 
+    /// <summary>Bare segment stamped by <c>AgentFrameworkUserAgentPolicy</c> in the non-hosted scenario; this policy upgrades it in-place when both run.</summary>
+    private const string BareAgentFrameworkPrefix = "agent-framework-dotnet/";
+
+    /// <summary>Combined hosted segment that this policy emits. Recognized in-place so callers whose pipelines already carry a (possibly different-version) combined segment get it replaced rather than double-prefixed (Q-D fix).</summary>
+    private const string CombinedHostedPrefix = "foundry-hosting/agent-framework-dotnet/";
+
     public override void Process(PipelineMessage message, IReadOnlyList<PipelinePolicy> pipeline, int currentIndex)
     {
         AppendHeader(message);
@@ -46,10 +62,49 @@ private static void AppendHeader(PipelineMessage message)
     {
         if (message.Request.Headers.TryGetValue("User-Agent", out var existing) && !string.IsNullOrEmpty(existing))
         {
-            // Guard against double-append on retries or when the policy
-            // is registered on multiple pipeline positions.
-            if (existing.Contains(s_supplementValue))
+            // Guard against double-append on retries or when the policy is registered on
+            // multiple pipeline positions.
+            if (existing!.Contains(s_supplementValue))
+            {
+                return;
+            }
+
+            // Combined-form check first: if the caller's pipeline already has
+            // `foundry-hosting/agent-framework-dotnet/{version}` (with a version that differs
+            // from ours — otherwise the .Contains above would have returned early), replace the
+            // entire combined span in place. Without this, the bare-prefix search below would
+            // match `agent-framework-dotnet/` *inside* the combined segment and produce a
+            // malformed `foundry-hosting/foundry-hosting/agent-framework-dotnet/...` value.
+            var combinedIdx = existing.IndexOf(CombinedHostedPrefix, StringComparison.Ordinal);
+            if (combinedIdx >= 0)
             {
+                var combinedEnd = existing.IndexOf(' ', combinedIdx);
+                if (combinedEnd < 0)
+                {
+                    combinedEnd = existing.Length;
+                }
+
+                var replacedCombined = string.Concat(existing.AsSpan(0, combinedIdx), s_supplementValue.AsSpan(), existing.AsSpan(combinedEnd));
+                message.Request.Headers.Set("User-Agent", replacedCombined);
+                return;
+            }
+
+            // If the bare agent-framework segment is present (stamped by
+            // AgentFrameworkUserAgentPolicy when not hosted), upgrade it in place to the
+            // combined hosted form so the wire never carries both segments simultaneously.
+            // Mirrors Python where get_user_agent() returns a single combined string when the
+            // hosted prefix is registered.
+            var idx = existing.IndexOf(BareAgentFrameworkPrefix, StringComparison.Ordinal);
+            if (idx >= 0)
+            {
+                var end = existing.IndexOf(' ', idx);
+                if (end < 0)
+                {
+                    end = existing.Length;
+                }
+
+                var replaced = string.Concat(existing.AsSpan(0, idx), s_supplementValue.AsSpan(), existing.AsSpan(end));
+                message.Request.Headers.Set("User-Agent", replaced);
                 return;
             }
 
 
@@ -23,7 +23,7 @@ namespace Azure.AI.Projects;
 /// Provides extension methods for <see cref="AIProjectClient"/>.
 /// </summary>
 [Experimental(DiagnosticIds.Experiments.AIOpenAIResponses)]
-public static partial class AzureAIProjectChatClientExtensions
+public static partial class AIProjectClientExtensions
 {
     /// <summary>
     /// Uses an existing server side agent, wrapped as a <see cref="ChatClientAgent"/> using the provided <see cref="AIProjectClient"/> and <see cref="AgentReference"/>.
@@ -63,7 +63,7 @@ public static FoundryAgent AsAIAgent(
             clientFactory,
             services);
 
-        return new FoundryAgent(aiProjectClient, innerAgent);
+        return new FoundryAgent(innerAgent);
     }
 
     /// <summary>
@@ -132,7 +132,7 @@ public static FoundryAgent AsAIAgent(
             !allowDeclarativeMode,
             services);
 
-        return new FoundryAgent(aiProjectClient, innerAgent);
+        return new FoundryAgent(innerAgent);
     }
 
     /// <summary>
@@ -165,7 +165,7 @@ public static FoundryAgent AsAIAgent(
             !allowDeclarativeMode,
             services);
 
-        return new FoundryAgent(aiProjectClient, innerAgent);
+        return new FoundryAgent(innerAgent);
     }
 
     /// <summary>
@@ -246,7 +246,7 @@ private static ChatClientAgent CreateChatClientAgent(
         Func<IChatClient, IChatClient>? clientFactory,
         IServiceProvider? services)
     {
-        IChatClient chatClient = new AzureAIProjectChatClient(aiProjectClient, agentVersion, agentOptions.ChatOptions);
+        IChatClient chatClient = new FoundryChatClient(aiProjectClient, agentVersion, agentOptions.ChatOptions);
 
         if (clientFactory is not null)
         {
@@ -268,10 +268,7 @@ private static ChatClientAgent CreateResponsesChatClientAgent(
         Throw.IfNull(agentOptions.ChatOptions);
         Throw.IfNullOrWhitespace(agentOptions.ChatOptions.ModelId);
 
-        IChatClient chatClient = aiProjectClient
-            .GetProjectOpenAIClient()
-            .GetResponsesClient()
-            .AsIChatClient(agentOptions.ChatOptions.ModelId);
+        IChatClient chatClient = new FoundryChatClient(aiProjectClient, agentOptions.ChatOptions.ModelId);
 
         if (clientFactory is not null)
         {
@@ -298,7 +295,7 @@ private static ChatClientAgent AsChatClientAgent(
         Func<IChatClient, IChatClient>? clientFactory,
         IServiceProvider? services)
     {
-        IChatClient chatClient = new AzureAIProjectChatClient(aiProjectClient, agentRecord, agentOptions.ChatOptions);
+        IChatClient chatClient = new FoundryChatClient(aiProjectClient, agentRecord, agentOptions.ChatOptions);
 
         if (clientFactory is not null)
         {
@@ -316,7 +313,7 @@ private static ChatClientAgent AsChatClientAgent(
         Func<IChatClient, IChatClient>? clientFactory,
         IServiceProvider? services)
     {
-        IChatClient chatClient = new AzureAIProjectChatClient(aiProjectClient, agentReference, defaultModelId: null, agentOptions.ChatOptions);
+        IChatClient chatClient = new FoundryChatClient(aiProjectClient, agentReference, defaultModelId: null, agentOptions.ChatOptions);
 
         if (clientFactory is not null)
         {
 
@@ -0,0 +1,88 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.ClientModel.Primitives;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Threading.Tasks;
+
+namespace Microsoft.Agents.AI.Foundry;
+
+/// <summary>
+/// Framework-wide pipeline policy that appends the <c>agent-framework-dotnet/{version}</c>
+/// segment to outgoing <c>User-Agent</c> headers, mirroring the
+/// <c>agent-framework-python/{version}</c> contract used by every Python provider package.
+/// </summary>
+/// <remarks>
+/// <para>
+/// The segment value is computed once from the <c>Microsoft.Agents.AI.Foundry</c> assembly's
+/// <see cref="AssemblyInformationalVersionAttribute"/>. The policy is idempotent on retries: if
+/// the segment is already present in the <c>User-Agent</c> header, the policy does not append
+/// it again.
+/// </para>
+/// <para>
+/// The policy is registered by <c>FoundryChatClient</c> on the underlying chat client's
+/// <c>OpenAIRequestPolicies</c> hook so every outbound Foundry call carries the segment. The
+/// policy is currently colocated with the Foundry package; it is expected to migrate to a
+/// framework-wide location (such as <c>Microsoft.Agents.AI</c>) once another provider package
+/// adopts the same User-Agent contract.
+/// </para>
+/// </remarks>
+internal sealed class AgentFrameworkUserAgentPolicy : PipelinePolicy
+{
+    /// <summary>Gets the singleton policy instance.</summary>
+    public static AgentFrameworkUserAgentPolicy Instance { get; } = new AgentFrameworkUserAgentPolicy();
+
+    private static readonly string s_segmentValue = CreateSegmentValue();
+
+    public override void Process(PipelineMessage message, IReadOnlyList<PipelinePolicy> pipeline, int currentIndex)
+    {
+        AppendHeader(message);
+        ProcessNext(message, pipeline, currentIndex);
+    }
+
+    public override async ValueTask ProcessAsync(PipelineMessage message, IReadOnlyList<PipelinePolicy> pipeline, int currentIndex)
+    {
+        AppendHeader(message);
+        await ProcessNextAsync(message, pipeline, currentIndex).ConfigureAwait(false);
+    }
+
+    private static void AppendHeader(PipelineMessage message)
+    {
+        if (message.Request.Headers.TryGetValue("User-Agent", out var existing) && !string.IsNullOrEmpty(existing))
+        {
+            // Guard against double-append on retries or when the policy
+            // is registered on multiple pipeline positions.
+            if (existing!.Contains(s_segmentValue))
+            {
+                return;
+            }
+
+            message.Request.Headers.Set("User-Agent", $"{existing} {s_segmentValue}");
+        }
+        else
+        {
+            message.Request.Headers.Set("User-Agent", s_segmentValue);
+        }
+    }
+
+    private static string CreateSegmentValue()
+    {
+        const string Name = "agent-framework-dotnet";
+
+        if (typeof(AgentFrameworkUserAgentPolicy).Assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion is string version)
+        {
+            int pos = version.IndexOf('+');
+            if (pos >= 0)
+            {
+                version = version.Substring(0, pos);
+            }
+
+            if (version.Length > 0)
+            {
+                return $"{Name}/{version}";
+            }
+        }
+
+        return Name;
+    }
+}
Original file line number	Diff line number	Diff line change
`@@ -23,7 +23,7 @@ namespace Azure.AI.Projects;`
`23`	`23`	`/// Provides extension methods for <see cref="AIProjectClient"/>.`
`24`	`24`	`/// </summary>`
`25`	`25`	`[Experimental(DiagnosticIds.Experiments.AIOpenAIResponses)]`
`26`		`-public static partial class AzureAIProjectChatClientExtensions`
	`26`	`+public static partial class AIProjectClientExtensions`
`27`	`27`	`{`
`28`	`28`	`/// <summary>`
`29`	`29`	`/// Uses an existing server side agent, wrapped as a <see cref="ChatClientAgent"/> using the provided <see cref="AIProjectClient"/> and <see cref="AgentReference"/>.`
`@@ -63,7 +63,7 @@ public static FoundryAgent AsAIAgent(`
`63`	`63`	`clientFactory,`
`64`	`64`	`services);`
`65`	`65`
`66`		`- return new FoundryAgent(aiProjectClient, innerAgent);`
	`66`	`+ return new FoundryAgent(innerAgent);`
`67`	`67`	`}`
`68`	`68`
`69`	`69`	`/// <summary>`
`@@ -132,7 +132,7 @@ public static FoundryAgent AsAIAgent(`
`132`	`132`	`!allowDeclarativeMode,`
`133`	`133`	`services);`
`134`	`134`
`135`		`- return new FoundryAgent(aiProjectClient, innerAgent);`
	`135`	`+ return new FoundryAgent(innerAgent);`
`136`	`136`	`}`
`137`	`137`
`138`	`138`	`/// <summary>`
`@@ -165,7 +165,7 @@ public static FoundryAgent AsAIAgent(`
`165`	`165`	`!allowDeclarativeMode,`
`166`	`166`	`services);`
`167`	`167`
`168`		`- return new FoundryAgent(aiProjectClient, innerAgent);`
	`168`	`+ return new FoundryAgent(innerAgent);`
`169`	`169`	`}`
`170`	`170`
`171`	`171`	`/// <summary>`
`@@ -246,7 +246,7 @@ private static ChatClientAgent CreateChatClientAgent(`
`246`	`246`	`Func<IChatClient, IChatClient>? clientFactory,`
`247`	`247`	`IServiceProvider? services)`
`248`	`248`	`{`
`249`		`- IChatClient chatClient = new AzureAIProjectChatClient(aiProjectClient, agentVersion, agentOptions.ChatOptions);`
	`249`	`+ IChatClient chatClient = new FoundryChatClient(aiProjectClient, agentVersion, agentOptions.ChatOptions);`
`250`	`250`
`251`	`251`	`if (clientFactory is not null)`
`252`	`252`	`{`
`@@ -268,10 +268,7 @@ private static ChatClientAgent CreateResponsesChatClientAgent(`
`268`	`268`	`Throw.IfNull(agentOptions.ChatOptions);`
`269`	`269`	`Throw.IfNullOrWhitespace(agentOptions.ChatOptions.ModelId);`
`270`	`270`
`271`		`- IChatClient chatClient = aiProjectClient`
`272`		`- .GetProjectOpenAIClient()`
`273`		`- .GetResponsesClient()`
`274`		`- .AsIChatClient(agentOptions.ChatOptions.ModelId);`
	`271`	`+ IChatClient chatClient = new FoundryChatClient(aiProjectClient, agentOptions.ChatOptions.ModelId);`
`275`	`272`
`276`	`273`	`if (clientFactory is not null)`
`277`	`274`	`{`
`@@ -298,7 +295,7 @@ private static ChatClientAgent AsChatClientAgent(`
`298`	`295`	`Func<IChatClient, IChatClient>? clientFactory,`
`299`	`296`	`IServiceProvider? services)`
`300`	`297`	`{`
`301`		`- IChatClient chatClient = new AzureAIProjectChatClient(aiProjectClient, agentRecord, agentOptions.ChatOptions);`
	`298`	`+ IChatClient chatClient = new FoundryChatClient(aiProjectClient, agentRecord, agentOptions.ChatOptions);`
`302`	`299`
`303`	`300`	`if (clientFactory is not null)`
`304`	`301`	`{`
`@@ -316,7 +313,7 @@ private static ChatClientAgent AsChatClientAgent(`
`316`	`313`	`Func<IChatClient, IChatClient>? clientFactory,`
`317`	`314`	`IServiceProvider? services)`
`318`	`315`	`{`
`319`		`- IChatClient chatClient = new AzureAIProjectChatClient(aiProjectClient, agentReference, defaultModelId: null, agentOptions.ChatOptions);`
	`316`	`+ IChatClient chatClient = new FoundryChatClient(aiProjectClient, agentReference, defaultModelId: null, agentOptions.ChatOptions);`
`320`	`317`
`321`	`318`	`if (clientFactory is not null)`
`322`	`319`	`{`