diff --git a/AGENTS.md b/AGENTS.md
new file mode 100644
index 00000000..f17c774a
--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,9 @@
+# Agent Instructions
+
+## XML documentation
+
+- Prefer `<see cref="..."/>` for linkable XML doc references, including explicit overloads like `<see cref="ForServiceUrl(Uri)"/>`; use `<c>...</c>` only for inline code formatting.
+
+## Pull requests
+
+- If a change breaks a public-facing API or behavior, call it out explicitly in the PR/review description.
diff --git a/core/src/Microsoft.Teams.Apps/Api/Clients/ActivityClient.cs b/core/src/Microsoft.Teams.Apps/Api/Clients/ActivityClient.cs
index 1cf236fa..8a1601fe 100644
--- a/core/src/Microsoft.Teams.Apps/Api/Clients/ActivityClient.cs
+++ b/core/src/Microsoft.Teams.Apps/Api/Clients/ActivityClient.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 using System.Diagnostics.CodeAnalysis;
+using Microsoft.Teams.Apps.Schema;
 using Microsoft.Teams.Core;
 using Microsoft.Teams.Core.Http;
 using Microsoft.Teams.Core.Schema;
@@ -19,52 +20,72 @@ public class ActivityClient
 {
     private readonly CoreConversationClient _client;
     private readonly Uri _serviceUrl;
+    private readonly AgenticIdentity? _defaultAgenticIdentity;
 
-    internal ActivityClient(Uri serviceUrl, CoreConversationClient client)
+    internal ActivityClient(Uri serviceUrl, CoreConversationClient client, AgenticIdentity? defaultAgenticIdentity = null)
     {
         _serviceUrl = serviceUrl;
         _client = client;
+        _defaultAgenticIdentity = defaultAgenticIdentity;
     }
 
     /// <summary>
     /// Create a new activity in a conversation.
     /// </summary>
-    public Task<SendActivityResponse?> CreateAsync(string conversationId, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<SendActivityResponse?> CreateAsync(string conversationId, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
-        activity.ServiceUrl ??= _serviceUrl;
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
         activity.Conversation ??= new Conversation(conversationId);
-        return _client.SendActivityAsync(activity, customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.SendActivityAsync(activity, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Update an existing activity in a conversation.
     /// </summary>
-    public Task<UpdateActivityResponse> UpdateAsync(string conversationId, string id, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<UpdateActivityResponse> UpdateAsync(string conversationId, string id, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
-        activity.ServiceUrl ??= _serviceUrl;
-        return _client.UpdateActivityAsync(conversationId, id, activity, requestContext: BotRequestContext.FromActivity(activity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
+        BotRequestContext? requestContext = BotRequestContext.Merge(
+            options.ToBotRequestContext(_defaultAgenticIdentity),
+            BotRequestContext.FromActivity(activity));
+        return _client.UpdateActivityAsync(conversationId, id, activity, requestContext: requestContext, cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Reply to an existing activity in a conversation.
     /// </summary>
-    public Task<SendActivityResponse?> ReplyAsync(string conversationId, string id, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<SendActivityResponse?> ReplyAsync(string conversationId, string id, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
         activity.ReplyToId = id;
-        activity.ServiceUrl ??= _serviceUrl;
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
         activity.Conversation ??= new Conversation(conversationId);
-        return _client.SendActivityAsync(activity, customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.SendActivityAsync(activity, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Delete an activity from a conversation.
     /// </summary>
-    public Task DeleteAsync(string conversationId, string id, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task DeleteAsync(string conversationId, string id, AgenticIdentity? agenticIdentity = null, CancellationToken cancellationToken = default)
+        => DeleteAsync(conversationId, id, new RequestOptions { AgenticIdentity = agenticIdentity }, cancellationToken);
+
+    /// <summary>
+    /// Delete an activity from a conversation.
+    /// </summary>
+    public Task DeleteAsync(string conversationId, string id, RequestOptions options, CancellationToken cancellationToken = default)
     {
-        return _client.DeleteActivityAsync(conversationId, id, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.DeleteActivityAsync(conversationId, id, options.ServiceUrl ?? _serviceUrl, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
+    }
+
+    /// <summary>
+    /// Get members of a specific activity.
+    /// </summary>
+    public async Task<IList<TeamsChannelAccount?>> GetMembersAsync(string conversationId, string id, RequestOptions options = default, CancellationToken cancellationToken = default)
+    {
+        IList<ChannelAccount> members = await _client.GetActivityMembersAsync(conversationId, id, options.ServiceUrl ?? _serviceUrl, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken).ConfigureAwait(false);
+        return [.. members.Select(m => TeamsChannelAccount.FromChannelAccount(m))];
     }
 
     /// <summary>
@@ -72,35 +93,44 @@ public Task DeleteAsync(string conversationId, string id, AgenticIdentity? agent
     /// Targeted activities are only visible to the specified recipient.
     /// </summary>
     [Experimental("ExperimentalTeamsTargeted")]
-    public Task<SendActivityResponse?> CreateTargetedAsync(string conversationId, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<SendActivityResponse?> CreateTargetedAsync(string conversationId, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
-        activity.ServiceUrl ??= _serviceUrl;
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
         activity.Conversation ??= new Conversation(conversationId);
         // Ensure recipient is marked as targeted
         if (activity.Recipient is not null)
         {
             activity.Recipient.IsTargeted = true;
         }
-        return _client.SendActivityAsync(activity, customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.SendActivityAsync(activity, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Update an existing targeted activity in a conversation.
     /// </summary>
     [Experimental("ExperimentalTeamsTargeted")]
-    public Task<UpdateActivityResponse> UpdateTargetedAsync(string conversationId, string id, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<UpdateActivityResponse> UpdateTargetedAsync(string conversationId, string id, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
-        activity.ServiceUrl ??= _serviceUrl;
-        return _client.UpdateTargetedActivityAsync(conversationId, id, activity, requestContext: BotRequestContext.FromActivity(activity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
+        BotRequestContext? requestContext = BotRequestContext.Merge(
+            options.ToBotRequestContext(_defaultAgenticIdentity),
+            BotRequestContext.FromActivity(activity));
+        return _client.UpdateTargetedActivityAsync(conversationId, id, activity, requestContext: requestContext, cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Delete a targeted activity from a conversation.
     /// </summary>
-    public Task DeleteTargetedAsync(string conversationId, string id, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task DeleteTargetedAsync(string conversationId, string id, AgenticIdentity? agenticIdentity = null, CancellationToken cancellationToken = default)
+        => DeleteTargetedAsync(conversationId, id, new RequestOptions { AgenticIdentity = agenticIdentity }, cancellationToken);
+
+    /// <summary>
+    /// Delete a targeted activity from a conversation.
+    /// </summary>
+    public Task DeleteTargetedAsync(string conversationId, string id, RequestOptions options, CancellationToken cancellationToken = default)
     {
-        return _client.DeleteTargetedActivityAsync(conversationId, id, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.DeleteTargetedActivityAsync(conversationId, id, options.ServiceUrl ?? _serviceUrl, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
     }
 }
diff --git a/core/src/Microsoft.Teams.Apps/Api/Clients/ApiClient.cs b/core/src/Microsoft.Teams.Apps/Api/Clients/ApiClient.cs
index 2d17636a..933a6524 100644
--- a/core/src/Microsoft.Teams.Apps/Api/Clients/ApiClient.cs
+++ b/core/src/Microsoft.Teams.Apps/Api/Clients/ApiClient.cs
@@ -3,7 +3,9 @@
 
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
+using Microsoft.Teams.Apps.Schema;
 using Microsoft.Teams.Core.Http;
+using Microsoft.Teams.Core.Schema;
 
 using CoreConversationClient = Microsoft.Teams.Core.ConversationClient;
 using CoreUserTokenClient = Microsoft.Teams.Core.UserTokenClient;
@@ -18,9 +20,9 @@ namespace Microsoft.Teams.Apps.Api.Clients;
 /// This client can be constructed in two ways:
 /// </para>
 /// <list type="bullet">
-/// <item><b>DI-friendly (no serviceUrl)</b> — Use <see cref="ApiClient(HttpClient, CoreConversationClient, CoreUserTokenClient, ILogger)"/>
-/// and call <see cref="ForServiceUrl"/> per-request to create a scoped instance.</item>
-/// <item><b>Fully initialized</b> — Use <see cref="ApiClient(Uri, HttpClient, CoreConversationClient, CoreUserTokenClient, ILogger)"/>
+/// <item><b>DI-friendly (no serviceUrl)</b> — Use <c>ApiClient(HttpClient, ConversationClient, UserTokenClient, ILogger)</c>
+/// and call <see cref="ForServiceUrl(Uri)"/>, <see cref="ForRequestOptions(RequestOptions)"/>, or <see cref="ForInboundActivity(TeamsActivity)"/> per-request to create a scoped instance.</item>
+/// <item><b>Fully initialized</b> — Use <c>ApiClient(Uri, HttpClient, ConversationClient, UserTokenClient, ILogger)</c>
 /// when the service URL is known upfront.</item>
 /// </list>
 /// </remarks>
@@ -32,10 +34,12 @@ public class ApiClient
 
     internal CoreUserTokenClient UserTokenClient { get; }
 
+    internal AgenticIdentity? DefaultAgenticIdentity { get; }
+
     /// <summary>
     /// The service URL used by this client.
     /// Null when constructed without a service URL (DI-friendly constructor).
-    /// Call <see cref="ForServiceUrl"/> to create a scoped instance with a service URL.
+    /// Call <see cref="ForServiceUrl(Uri)"/> or <see cref="ForRequestOptions(RequestOptions)"/> to create a scoped instance with a service URL.
     /// </summary>
     public virtual Uri ServiceUrl { get; }
 
@@ -64,7 +68,7 @@ public class ApiClient
 
     /// <summary>
     /// Creates a new <see cref="ApiClient"/> without a service URL (DI-friendly).
-    /// Use <see cref="ForServiceUrl"/> to create a scoped instance bound to a specific service URL.
+    /// Use <see cref="ForServiceUrl(Uri)"/> to create a scoped instance bound to a specific service URL.
     /// </summary>
     /// <param name="httpClient">An <see cref="HttpClient"/> configured with authentication (e.g., via DI with <c>BotAuthenticationHandler</c>).</param>
     /// <param name="conversationClient">The core conversation client for conversation/activity/member operations.</param>
@@ -80,6 +84,7 @@ internal ApiClient(HttpClient httpClient, CoreConversationClient conversationCli
         _http = new BotHttpClient(httpClient, logger);
         ConversationClient = conversationClient;
         UserTokenClient = userTokenClient;
+        DefaultAgenticIdentity = null;
 
         // ServiceUrl-dependent sub-clients require ForServiceUrl() before use
         ServiceUrl = null!;
@@ -96,7 +101,8 @@ internal ApiClient(HttpClient httpClient, CoreConversationClient conversationCli
     /// <param name="conversationClient">The core conversation client for conversation/activity/member operations.</param>
     /// <param name="userTokenClient">The core user token client for sign-in and token operations.</param>
     /// <param name="logger">Optional logger.</param>
-    internal ApiClient(Uri serviceUrl, HttpClient httpClient, CoreConversationClient conversationClient, CoreUserTokenClient userTokenClient, ILogger? logger = null)
+    /// <param name="defaultAgenticIdentity">Optional default agentic identity for service URL-bound sub-clients.</param>
+    internal ApiClient(Uri serviceUrl, HttpClient httpClient, CoreConversationClient conversationClient, CoreUserTokenClient userTokenClient, ILogger? logger = null, AgenticIdentity? defaultAgenticIdentity = null)
     {
         ArgumentNullException.ThrowIfNull(serviceUrl);
         ArgumentNullException.ThrowIfNull(httpClient);
@@ -106,22 +112,26 @@ internal ApiClient(Uri serviceUrl, HttpClient httpClient, CoreConversationClient
         _http = new BotHttpClient(httpClient, logger);
         ConversationClient = conversationClient;
         UserTokenClient = userTokenClient;
+        DefaultAgenticIdentity = defaultAgenticIdentity;
         ServiceUrl = serviceUrl;
-        Conversations = new ConversationApiClient(serviceUrl, conversationClient);
-        Teams = new TeamClient(serviceUrl.ToString(), _http);
-        Meetings = new MeetingClient(serviceUrl.ToString(), _http);
+        Conversations = new ConversationApiClient(serviceUrl, conversationClient, DefaultAgenticIdentity);
+        Teams = new TeamClient(serviceUrl.ToString(), _http, DefaultAgenticIdentity);
+        Meetings = new MeetingClient(serviceUrl.ToString(), _http, DefaultAgenticIdentity);
     }
 
-    // Private constructor for ForServiceUrl — shares BotHttpClient, ConversationClient, and UserTokenClient
-    private ApiClient(BotHttpClient http, CoreConversationClient conversationClient, CoreUserTokenClient userTokenClient, Uri serviceUrl)
+    // Private constructor for scoped clients — shares BotHttpClient, ConversationClient, and UserTokenClient
+    private ApiClient(BotHttpClient http, CoreConversationClient conversationClient, CoreUserTokenClient userTokenClient, RequestOptions options)
     {
+        Uri serviceUrl = options.ServiceUrl ?? throw new InvalidOperationException("RequestOptions.ServiceUrl is required to scope the Api client.");
+
         _http = http;
         ConversationClient = conversationClient;
         UserTokenClient = userTokenClient;
+        DefaultAgenticIdentity = options.AgenticIdentity;
         ServiceUrl = serviceUrl;
-        Conversations = new ConversationApiClient(serviceUrl, conversationClient);
-        Teams = new TeamClient(serviceUrl.ToString(), http);
-        Meetings = new MeetingClient(serviceUrl.ToString(), http);
+        Conversations = new ConversationApiClient(serviceUrl, conversationClient, DefaultAgenticIdentity);
+        Teams = new TeamClient(serviceUrl.ToString(), http, DefaultAgenticIdentity);
+        Meetings = new MeetingClient(serviceUrl.ToString(), http, DefaultAgenticIdentity);
     }
 
     /// <summary>
@@ -133,6 +143,33 @@ private ApiClient(BotHttpClient http, CoreConversationClient conversationClient,
     public virtual ApiClient ForServiceUrl(Uri serviceUrl)
     {
         ArgumentNullException.ThrowIfNull(serviceUrl);
-        return new ApiClient(_http, ConversationClient, UserTokenClient, serviceUrl);
+        return ForRequestOptions(new RequestOptions { ServiceUrl = serviceUrl });
+    }
+
+    /// <summary>
+    /// Creates a new <see cref="ApiClient"/> with defaults from the request options.
+    /// </summary>
+    /// <param name="options">The request options. <see cref="RequestOptions.ServiceUrl"/> is required.</param>
+    /// <returns>A new <see cref="ApiClient"/> bound to the request options.</returns>
+    /// <exception cref="InvalidOperationException">Thrown when <see cref="RequestOptions.ServiceUrl"/> is not provided.</exception>
+    public virtual ApiClient ForRequestOptions(RequestOptions options)
+    {
+        return new ApiClient(_http, ConversationClient, UserTokenClient, options);
+    }
+
+    /// <summary>
+    /// Creates a new <see cref="ApiClient"/> with defaults from the inbound activity.
+    /// </summary>
+    /// <param name="activity">The inbound activity that supplies defaults for this scope.</param>
+    /// <returns>A new <see cref="ApiClient"/> with defaults from the inbound activity.</returns>
+    /// <exception cref="InvalidOperationException">Thrown when <paramref name="activity"/> does not include required API defaults.</exception>
+    public virtual ApiClient ForInboundActivity(TeamsActivity activity)
+    {
+        ArgumentNullException.ThrowIfNull(activity);
+        return ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = activity.ServiceUrl ?? throw new InvalidOperationException("Activity.ServiceUrl is required to use the Api client."),
+            AgenticIdentity = activity.Recipient?.GetAgenticIdentity()
+        });
     }
 }
diff --git a/core/src/Microsoft.Teams.Apps/Api/Clients/ConversationApiClient.cs b/core/src/Microsoft.Teams.Apps/Api/Clients/ConversationApiClient.cs
index 26b49bd0..df6f2471 100644
--- a/core/src/Microsoft.Teams.Apps/Api/Clients/ConversationApiClient.cs
+++ b/core/src/Microsoft.Teams.Apps/Api/Clients/ConversationApiClient.cs
@@ -20,6 +20,7 @@ public class ConversationApiClient
 {
     private readonly CoreConversationClient _client;
     private readonly Uri _serviceUrl;
+    private readonly AgenticIdentity? _defaultAgenticIdentity;
 
     /// <summary>
     /// Client for activity operations.
@@ -39,14 +40,15 @@ public class ConversationApiClient
     [Obsolete("Use ConversationApiClient.AddReactionAsync and ConversationApiClient.DeleteReactionAsync instead.")]
     public ReactionClient Reactions { get; }
 
-    internal ConversationApiClient(Uri serviceUrl, CoreConversationClient client)
+    internal ConversationApiClient(Uri serviceUrl, CoreConversationClient client, AgenticIdentity? defaultAgenticIdentity = null)
     {
         _serviceUrl = serviceUrl;
         _client = client;
+        _defaultAgenticIdentity = defaultAgenticIdentity;
 #pragma warning disable CS0618 // Suppress obsolete warnings for backward-compatible initialization
-        Activities = new ActivityClient(serviceUrl, client);
-        Members = new MemberClient(serviceUrl, client);
-        Reactions = new ReactionClient(serviceUrl, client);
+        Activities = new ActivityClient(serviceUrl, client, defaultAgenticIdentity);
+        Members = new MemberClient(serviceUrl, client, defaultAgenticIdentity);
+        Reactions = new ReactionClient(serviceUrl, client, defaultAgenticIdentity);
 #pragma warning restore CS0618
     }
 
@@ -55,7 +57,7 @@ internal ConversationApiClient(Uri serviceUrl, CoreConversationClient client)
     /// </summary>
     public Task<CreateConversationResponse> CreateAsync(ConversationParameters request, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
     {
-        return _client.CreateConversationAsync(request, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.CreateConversationAsync(request, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
     }
 
     #region Activity Methods
@@ -63,42 +65,60 @@ public Task<CreateConversationResponse> CreateAsync(ConversationParameters reque
     /// <summary>
     /// Create a new activity in a conversation.
     /// </summary>
-    public Task<SendActivityResponse?> CreateActivityAsync(string conversationId, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<SendActivityResponse?> CreateActivityAsync(string conversationId, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
-        activity.ServiceUrl ??= _serviceUrl;
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
         activity.Conversation ??= new Conversation(conversationId);
-        return _client.SendActivityAsync(activity, customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.SendActivityAsync(activity, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Update an existing activity in a conversation.
     /// </summary>
-    public Task<UpdateActivityResponse> UpdateActivityAsync(string conversationId, string id, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<UpdateActivityResponse> UpdateActivityAsync(string conversationId, string id, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
-        activity.ServiceUrl ??= _serviceUrl;
-        return _client.UpdateActivityAsync(conversationId, id, activity, requestContext: BotRequestContext.FromActivity(activity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
+        BotRequestContext? requestContext = BotRequestContext.Merge(
+            options.ToBotRequestContext(_defaultAgenticIdentity),
+            BotRequestContext.FromActivity(activity));
+        return _client.UpdateActivityAsync(conversationId, id, activity, requestContext: requestContext, cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Reply to an existing activity in a conversation.
     /// </summary>
-    public Task<SendActivityResponse?> ReplyToActivityAsync(string conversationId, string id, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<SendActivityResponse?> ReplyToActivityAsync(string conversationId, string id, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
         activity.ReplyToId = id;
-        activity.ServiceUrl ??= _serviceUrl;
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
         activity.Conversation ??= new Conversation(conversationId);
-        return _client.SendActivityAsync(activity, customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.SendActivityAsync(activity, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Delete an activity from a conversation.
     /// </summary>
-    public Task DeleteActivityAsync(string conversationId, string id, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task DeleteActivityAsync(string conversationId, string id, AgenticIdentity? agenticIdentity = null, CancellationToken cancellationToken = default)
+        => DeleteActivityAsync(conversationId, id, new RequestOptions { AgenticIdentity = agenticIdentity }, cancellationToken);
+
+    /// <summary>
+    /// Delete an activity from a conversation.
+    /// </summary>
+    public Task DeleteActivityAsync(string conversationId, string id, RequestOptions options, CancellationToken cancellationToken = default)
+    {
+        return _client.DeleteActivityAsync(conversationId, id, options.ServiceUrl ?? _serviceUrl, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
+    }
+
+    /// <summary>
+    /// Get members of a specific activity.
+    /// </summary>
+    public async Task<IList<TeamsChannelAccount?>> GetActivityMembersAsync(string conversationId, string id, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
-        return _client.DeleteActivityAsync(conversationId, id, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        IList<ChannelAccount> members = await _client.GetActivityMembersAsync(conversationId, id, options.ServiceUrl ?? _serviceUrl, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken).ConfigureAwait(false);
+        return [.. members.Select(m => TeamsChannelAccount.FromChannelAccount(m))];
     }
 
     /// <summary>
@@ -106,35 +126,44 @@ public Task DeleteActivityAsync(string conversationId, string id, AgenticIdentit
     /// Targeted activities are only visible to the specified recipient.
     /// </summary>
     [Experimental("ExperimentalTeamsTargeted")]
-    public Task<SendActivityResponse?> CreateTargetedActivityAsync(string conversationId, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<SendActivityResponse?> CreateTargetedActivityAsync(string conversationId, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
-        activity.ServiceUrl ??= _serviceUrl;
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
         activity.Conversation ??= new Conversation(conversationId);
         if (activity.Recipient is not null)
         {
             activity.Recipient.IsTargeted = true;
         }
-        return _client.SendActivityAsync(activity, customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.SendActivityAsync(activity, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Update an existing targeted activity in a conversation.
     /// </summary>
     [Experimental("ExperimentalTeamsTargeted")]
-    public Task<UpdateActivityResponse> UpdateTargetedActivityAsync(string conversationId, string id, CoreActivity activity, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task<UpdateActivityResponse> UpdateTargetedActivityAsync(string conversationId, string id, CoreActivity activity, RequestOptions options = default, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(activity);
-        activity.ServiceUrl ??= _serviceUrl;
-        return _client.UpdateTargetedActivityAsync(conversationId, id, activity, requestContext: BotRequestContext.FromActivity(activity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        activity.ServiceUrl ??= options.ServiceUrl ?? _serviceUrl;
+        BotRequestContext? requestContext = BotRequestContext.Merge(
+            options.ToBotRequestContext(_defaultAgenticIdentity),
+            BotRequestContext.FromActivity(activity));
+        return _client.UpdateTargetedActivityAsync(conversationId, id, activity, requestContext: requestContext, cancellationToken: cancellationToken);
     }
 
     /// <summary>
     /// Delete a targeted activity from a conversation.
     /// </summary>
-    public Task DeleteTargetedActivityAsync(string conversationId, string id, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
+    public Task DeleteTargetedActivityAsync(string conversationId, string id, AgenticIdentity? agenticIdentity = null, CancellationToken cancellationToken = default)
+        => DeleteTargetedActivityAsync(conversationId, id, new RequestOptions { AgenticIdentity = agenticIdentity }, cancellationToken);
+
+    /// <summary>
+    /// Delete a targeted activity from a conversation.
+    /// </summary>
+    public Task DeleteTargetedActivityAsync(string conversationId, string id, RequestOptions options, CancellationToken cancellationToken = default)
     {
-        return _client.DeleteTargetedActivityAsync(conversationId, id, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.DeleteTargetedActivityAsync(conversationId, id, options.ServiceUrl ?? _serviceUrl, requestContext: options.ToBotRequestContext(_defaultAgenticIdentity), cancellationToken: cancellationToken);
     }
 
     #endregion
@@ -147,7 +176,7 @@ public Task DeleteTargetedActivityAsync(string conversationId, string id, Agenti
     [Obsolete("Use GetMembersPagedAsync instead.")]
     public async Task<IList<TeamsChannelAccount?>> GetMembersAsync(string conversationId, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
     {
-        IList<ChannelAccount> members = await _client.GetConversationMembersAsync(conversationId, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken).ConfigureAwait(false);
+        IList<ChannelAccount> members = await _client.GetConversationMembersAsync(conversationId, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken).ConfigureAwait(false);
         return [.. members.Select(m => TeamsChannelAccount.FromChannelAccount(m))];
     }
 
@@ -167,7 +196,7 @@ public async Task<PagedTeamsMembersResult> GetMembersPagedAsync(
             _serviceUrl,
             pageSize,
             continuationToken,
-            requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity),
+            requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity),
             customHeaders: additionalHeaders,
             cancellationToken: cancellationToken).ConfigureAwait(false);
         PagedTeamsMembersResult result = new();
@@ -226,7 +255,7 @@ public async IAsyncEnumerable<TeamsChannelAccount> GetAllMembersAsync(
     /// </summary>
     public Task<T> GetMemberByIdAsync<T>(string conversationId, string memberId, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default) where T : ChannelAccount
     {
-        return _client.GetConversationMemberAsync<T>(conversationId, memberId, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.GetConversationMemberAsync<T>(conversationId, memberId, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
     }
 
     /// <summary>
@@ -253,7 +282,7 @@ public Task<T> GetMemberByIdAsync<T>(string conversationId, string memberId, Age
     /// <param name="cancellationToken">A <see cref="CancellationToken"/> to observe while waiting for the task to complete.</param>
     public Task AddReactionAsync(string conversationId, string activityId, string reactionType, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
     {
-        return _client.AddReactionAsync(conversationId, activityId, reactionType, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.AddReactionAsync(conversationId, activityId, reactionType, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
     }
 
     /// <summary>
@@ -267,7 +296,7 @@ public Task AddReactionAsync(string conversationId, string activityId, string re
     /// <param name="cancellationToken">A <see cref="CancellationToken"/> to observe while waiting for the task to complete.</param>
     public Task DeleteReactionAsync(string conversationId, string activityId, string reactionType, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
     {
-        return _client.DeleteReactionAsync(conversationId, activityId, reactionType, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.DeleteReactionAsync(conversationId, activityId, reactionType, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
     }
 
     #endregion
diff --git a/core/src/Microsoft.Teams.Apps/Api/Clients/MeetingClient.cs b/core/src/Microsoft.Teams.Apps/Api/Clients/MeetingClient.cs
index 43485ee3..c8bdd4d5 100644
--- a/core/src/Microsoft.Teams.Apps/Api/Clients/MeetingClient.cs
+++ b/core/src/Microsoft.Teams.Apps/Api/Clients/MeetingClient.cs
@@ -14,11 +14,13 @@ public class MeetingClient
 {
     private readonly BotHttpClient _http;
     private readonly string _serviceUrl;
+    private readonly AgenticIdentity? _defaultAgenticIdentity;
 
-    internal MeetingClient(string serviceUrl, BotHttpClient http)
+    internal MeetingClient(string serviceUrl, BotHttpClient http, AgenticIdentity? defaultAgenticIdentity = null)
     {
         _serviceUrl = serviceUrl.TrimEnd('/');
         _http = http;
+        _defaultAgenticIdentity = defaultAgenticIdentity;
     }
 
     /// <summary>
@@ -27,7 +29,7 @@ internal MeetingClient(string serviceUrl, BotHttpClient http)
     public async Task<Meeting?> GetByIdAsync(string id, AgenticIdentity? agenticIdentity = null, CancellationToken cancellationToken = default)
     {
         string url = $"{_serviceUrl}/v1/meetings/{Uri.EscapeDataString(id)}";
-        return await _http.SendAsync<Meeting>(HttpMethod.Get, url, body: null, options: CreateRequestOptions(agenticIdentity), cancellationToken).ConfigureAwait(false);
+        return await _http.SendAsync<Meeting>(HttpMethod.Get, url, body: null, options: new BotRequestOptions { RequestContext = BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity) }, cancellationToken).ConfigureAwait(false);
     }
 
     /// <summary>
@@ -36,11 +38,8 @@ internal MeetingClient(string serviceUrl, BotHttpClient http)
     public async Task<MeetingParticipant?> GetParticipantAsync(string meetingId, string id, string tenantId, AgenticIdentity? agenticIdentity = null, CancellationToken cancellationToken = default)
     {
         string url = $"{_serviceUrl}/v1/meetings/{Uri.EscapeDataString(meetingId)}/participants/{Uri.EscapeDataString(id)}?tenantId={Uri.EscapeDataString(tenantId)}";
-        return await _http.SendAsync<MeetingParticipant>(HttpMethod.Get, url, body: null, options: CreateRequestOptions(agenticIdentity), cancellationToken).ConfigureAwait(false);
+        return await _http.SendAsync<MeetingParticipant>(HttpMethod.Get, url, body: null, options: new BotRequestOptions { RequestContext = BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity) }, cancellationToken).ConfigureAwait(false);
     }
-
-    private static BotRequestOptions? CreateRequestOptions(AgenticIdentity? agenticIdentity) =>
-        agenticIdentity is null ? null : new() { RequestContext = BotRequestContext.FromAgenticIdentity(agenticIdentity) };
 }
 
 /// <summary>
diff --git a/core/src/Microsoft.Teams.Apps/Api/Clients/MemberClient.cs b/core/src/Microsoft.Teams.Apps/Api/Clients/MemberClient.cs
index cfd05b82..bb8d23fd 100644
--- a/core/src/Microsoft.Teams.Apps/Api/Clients/MemberClient.cs
+++ b/core/src/Microsoft.Teams.Apps/Api/Clients/MemberClient.cs
@@ -20,11 +20,13 @@ public class MemberClient
 {
     private readonly CoreConversationClient _client;
     private readonly Uri _serviceUrl;
+    private readonly AgenticIdentity? _defaultAgenticIdentity;
 
-    internal MemberClient(Uri serviceUrl, CoreConversationClient client)
+    internal MemberClient(Uri serviceUrl, CoreConversationClient client, AgenticIdentity? defaultAgenticIdentity = null)
     {
         _serviceUrl = serviceUrl;
         _client = client;
+        _defaultAgenticIdentity = defaultAgenticIdentity;
     }
 
     /// <summary>
@@ -33,7 +35,7 @@ internal MemberClient(Uri serviceUrl, CoreConversationClient client)
     [Obsolete("Use GetPagedAsync instead.")]
     public async Task<IList<TeamsChannelAccount?>> GetAsync(string conversationId, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
     {
-        IList<ChannelAccount> members = await _client.GetConversationMembersAsync(conversationId, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken).ConfigureAwait(false);
+        IList<ChannelAccount> members = await _client.GetConversationMembersAsync(conversationId, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken).ConfigureAwait(false);
         return [.. members.Select(m => TeamsChannelAccount.FromChannelAccount(m))];
     }
 
@@ -53,7 +55,7 @@ public async Task<PagedTeamsMembersResult> GetPagedAsync(
             _serviceUrl,
             pageSize,
             continuationToken,
-            requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity),
+            requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity),
             customHeaders: additionalHeaders,
             cancellationToken: cancellationToken).ConfigureAwait(false);
         PagedTeamsMembersResult result = new();
@@ -112,7 +114,7 @@ public async IAsyncEnumerable<TeamsChannelAccount> GetAllAsync(
     /// </summary>
     public Task<T> GetByIdAsync<T>(string conversationId, string memberId, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default) where T : ChannelAccount
     {
-        return _client.GetConversationMemberAsync<T>(conversationId, memberId, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.GetConversationMemberAsync<T>(conversationId, memberId, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
     }
 
     /// <summary>
diff --git a/core/src/Microsoft.Teams.Apps/Api/Clients/ReactionClient.cs b/core/src/Microsoft.Teams.Apps/Api/Clients/ReactionClient.cs
index 88419ec9..3b6e64ed 100644
--- a/core/src/Microsoft.Teams.Apps/Api/Clients/ReactionClient.cs
+++ b/core/src/Microsoft.Teams.Apps/Api/Clients/ReactionClient.cs
@@ -17,11 +17,13 @@ public class ReactionClient
 {
     private readonly CoreConversationClient _client;
     private readonly Uri _serviceUrl;
+    private readonly AgenticIdentity? _defaultAgenticIdentity;
 
-    internal ReactionClient(Uri serviceUrl, CoreConversationClient client)
+    internal ReactionClient(Uri serviceUrl, CoreConversationClient client, AgenticIdentity? defaultAgenticIdentity = null)
     {
         _serviceUrl = serviceUrl;
         _client = client;
+        _defaultAgenticIdentity = defaultAgenticIdentity;
     }
 
     /// <summary>
@@ -35,7 +37,7 @@ internal ReactionClient(Uri serviceUrl, CoreConversationClient client)
     /// <param name="cancellationToken">A <see cref="CancellationToken"/> to observe while waiting for the task to complete.</param>
     public Task AddAsync(string conversationId, string activityId, string reactionType, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
     {
-        return _client.AddReactionAsync(conversationId, activityId, reactionType, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.AddReactionAsync(conversationId, activityId, reactionType, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
     }
 
     /// <summary>
@@ -49,6 +51,6 @@ public Task AddAsync(string conversationId, string activityId, string reactionTy
     /// <param name="cancellationToken">A <see cref="CancellationToken"/> to observe while waiting for the task to complete.</param>
     public Task DeleteAsync(string conversationId, string activityId, string reactionType, AgenticIdentity? agenticIdentity = null, Dictionary<string, string>? additionalHeaders = null, CancellationToken cancellationToken = default)
     {
-        return _client.DeleteReactionAsync(conversationId, activityId, reactionType, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
+        return _client.DeleteReactionAsync(conversationId, activityId, reactionType, _serviceUrl, requestContext: BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity), customHeaders: additionalHeaders, cancellationToken: cancellationToken);
     }
 }
diff --git a/core/src/Microsoft.Teams.Apps/Api/Clients/RequestOptions.cs b/core/src/Microsoft.Teams.Apps/Api/Clients/RequestOptions.cs
new file mode 100644
index 00000000..1a3c5e73
--- /dev/null
+++ b/core/src/Microsoft.Teams.Apps/Api/Clients/RequestOptions.cs
@@ -0,0 +1,31 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using Microsoft.Teams.Core.Http;
+using Microsoft.Teams.Core.Schema;
+
+namespace Microsoft.Teams.Apps.Api.Clients;
+
+/// <summary>
+/// Options for Apps API requests that need per-call settings beyond the required method parameters.
+/// </summary>
+public readonly record struct RequestOptions
+{
+    /// <summary>
+    /// Gets the service URL for this request.
+    /// </summary>
+    public Uri? ServiceUrl { get; init; }
+
+    /// <summary>
+    /// Gets the agentic identity to authenticate as for this request.
+    /// </summary>
+    public AgenticIdentity? AgenticIdentity { get; init; }
+
+    internal BotRequestContext? ToBotRequestContext(AgenticIdentity? defaultAgenticIdentity = null)
+        => BotRequestContext.FromAgenticIdentity(AgenticIdentity ?? defaultAgenticIdentity);
+
+    internal BotRequestOptions? ToBotRequestOptions(AgenticIdentity? defaultAgenticIdentity = null)
+        => ToBotRequestContext(defaultAgenticIdentity) is { } requestContext
+            ? new BotRequestOptions { RequestContext = requestContext }
+            : null;
+}
diff --git a/core/src/Microsoft.Teams.Apps/Api/Clients/TeamClient.cs b/core/src/Microsoft.Teams.Apps/Api/Clients/TeamClient.cs
index 4b3dd905..5e9de7ed 100644
--- a/core/src/Microsoft.Teams.Apps/Api/Clients/TeamClient.cs
+++ b/core/src/Microsoft.Teams.Apps/Api/Clients/TeamClient.cs
@@ -15,11 +15,13 @@ public class TeamClient
 {
     private readonly BotHttpClient _http;
     private readonly string _serviceUrl;
+    private readonly AgenticIdentity? _defaultAgenticIdentity;
 
-    internal TeamClient(string serviceUrl, BotHttpClient http)
+    internal TeamClient(string serviceUrl, BotHttpClient http, AgenticIdentity? defaultAgenticIdentity = null)
     {
         _serviceUrl = serviceUrl.TrimEnd('/');
         _http = http;
+        _defaultAgenticIdentity = defaultAgenticIdentity;
     }
 
     /// <summary>
@@ -28,7 +30,7 @@ internal TeamClient(string serviceUrl, BotHttpClient http)
     public async Task<Team?> GetByIdAsync(string id, AgenticIdentity? agenticIdentity = null, CancellationToken cancellationToken = default)
     {
         string url = $"{_serviceUrl}/v3/teams/{Uri.EscapeDataString(id)}";
-        return await _http.SendAsync<Team>(HttpMethod.Get, url, body: null, options: CreateRequestOptions(agenticIdentity), cancellationToken).ConfigureAwait(false);
+        return await _http.SendAsync<Team>(HttpMethod.Get, url, body: null, options: new BotRequestOptions { RequestContext = BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity) }, cancellationToken).ConfigureAwait(false);
     }
 
     /// <summary>
@@ -37,13 +39,10 @@ internal TeamClient(string serviceUrl, BotHttpClient http)
     public async Task<List<TeamsChannel>?> GetConversationsAsync(string id, AgenticIdentity? agenticIdentity = null, CancellationToken cancellationToken = default)
     {
         string url = $"{_serviceUrl}/v3/teams/{Uri.EscapeDataString(id)}/conversations";
-        ConversationListResponse? response = await _http.SendAsync<ConversationListResponse>(HttpMethod.Get, url, body: null, options: CreateRequestOptions(agenticIdentity), cancellationToken).ConfigureAwait(false);
+        ConversationListResponse? response = await _http.SendAsync<ConversationListResponse>(HttpMethod.Get, url, body: null, options: new BotRequestOptions { RequestContext = BotRequestContext.FromAgenticIdentity(agenticIdentity ?? _defaultAgenticIdentity) }, cancellationToken).ConfigureAwait(false);
         return response?.Conversations;
     }
 
-    private static BotRequestOptions? CreateRequestOptions(AgenticIdentity? agenticIdentity) =>
-        agenticIdentity is null ? null : new() { RequestContext = BotRequestContext.FromAgenticIdentity(agenticIdentity) };
-
     private sealed class ConversationListResponse
     {
         [JsonPropertyName("conversations")]
diff --git a/core/src/Microsoft.Teams.Apps/Context.cs b/core/src/Microsoft.Teams.Apps/Context.cs
index 53851f38..a4bc2b45 100644
--- a/core/src/Microsoft.Teams.Apps/Context.cs
+++ b/core/src/Microsoft.Teams.Apps/Context.cs
@@ -48,8 +48,7 @@ public class Context<TActivity>(TeamsBotApplication botApplication, TActivity ac
     /// <summary>
     /// Gets the <see cref="ApiClient"/> scoped to the current activity's service URL.
     /// </summary>
-    public ApiClient Api => _api ??= TeamsBotApplication.Api.ForServiceUrl(
-        Activity.ServiceUrl ?? throw new InvalidOperationException("Activity.ServiceUrl is required to use the Api client."));
+    public ApiClient Api => _api ??= TeamsBotApplication.Api.ForInboundActivity(Activity);
 
     // ==================== Turn State ====================
 
diff --git a/core/src/Microsoft.Teams.Apps/TeamsBotApplication.HostingExtensions.cs b/core/src/Microsoft.Teams.Apps/TeamsBotApplication.HostingExtensions.cs
index 9f9bc60c..38eaef2b 100644
--- a/core/src/Microsoft.Teams.Apps/TeamsBotApplication.HostingExtensions.cs
+++ b/core/src/Microsoft.Teams.Apps/TeamsBotApplication.HostingExtensions.cs
@@ -115,7 +115,11 @@ public static IServiceCollection AddTeamsBotApplication<TApp>(this IServiceColle
         BotConfig botConfig = BotConfig.Resolve(services, sectionName);
 
         // Register TeamsBotApplicationOptions
-        TeamsBotApplicationOptions teamsOptions = new() { AppId = botConfig.ClientId };
+        TeamsBotApplicationOptions teamsOptions = new()
+        {
+            AppId = botConfig.ClientId,
+            TenantId = string.IsNullOrWhiteSpace(botConfig.TenantId) ? null : botConfig.TenantId
+        };
         configure?.Invoke(teamsOptions);
         services.AddSingleton(teamsOptions);
 
diff --git a/core/src/Microsoft.Teams.Apps/TeamsBotApplication.cs b/core/src/Microsoft.Teams.Apps/TeamsBotApplication.cs
index f273c8e9..9116b424 100644
--- a/core/src/Microsoft.Teams.Apps/TeamsBotApplication.cs
+++ b/core/src/Microsoft.Teams.Apps/TeamsBotApplication.cs
@@ -21,6 +21,7 @@ namespace Microsoft.Teams.Apps;
 public class TeamsBotApplication : BotApplication
 {
     private readonly TurnStateLoader? _stateLoader;
+    private readonly string? _tenantId;
     private Uri? _lastServiceUrl;
 
     /// <summary>
@@ -112,6 +113,7 @@ public TeamsBotApplication(
             options)
     {
         _stateLoader = stateLoader;
+        _tenantId = string.IsNullOrWhiteSpace(options?.TenantId) ? null : options.TenantId;
         Api = teamsApiClient;
         Logger = logger;
         Router = new Router(logger);
@@ -217,6 +219,7 @@ public TeamsBotApplication(
                 AgenticAppId = agenticIdentity.AgenticAppId,
                 AgenticUserId = agenticIdentity.AgenticUserId,
                 AgenticAppBlueprintId = agenticIdentity.AgenticAppBlueprintId,
+                TenantId = agenticIdentity.TenantId,
             });
         }
 
@@ -241,6 +244,33 @@ public TeamsBotApplication(
         return SendAsync(threadedConversationId, text, agenticIdentity: agenticIdentity, cancellationToken: cancellationToken);
     }
 
+    /// <summary>
+    /// Creates an agentic identity using this application's defaults.
+    /// </summary>
+    /// <remarks>
+    /// The agentic app blueprint ID defaults to <see cref="BotApplication.AppId"/>.
+    /// The tenant ID defaults to the configured <see cref="TeamsBotApplicationOptions.TenantId"/> when available;
+    /// otherwise it remains null unless explicitly provided.
+    /// </remarks>
+    /// <param name="agenticAppId">The agentic application ID.</param>
+    /// <param name="agenticUserId">The agentic user ID.</param>
+    /// <param name="tenantId">Optional tenant ID of the agent instance for multi-tenant applications. Overrides the configured tenant ID when provided.</param>
+    /// <param name="agenticAppBlueprintId">Optional agentic application blueprint ID. Defaults to this application's AppId.</param>
+    /// <returns>An <see cref="AgenticIdentity"/> populated with application defaults.</returns>
+    public AgenticIdentity GetAgenticIdentity(string agenticAppId, string agenticUserId, string? tenantId = null, string? agenticAppBlueprintId = null)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(agenticAppId);
+        ArgumentException.ThrowIfNullOrWhiteSpace(agenticUserId);
+
+        return new AgenticIdentity
+        {
+            AgenticAppId = agenticAppId,
+            AgenticUserId = agenticUserId,
+            TenantId = tenantId ?? _tenantId,
+            AgenticAppBlueprintId = agenticAppBlueprintId ?? AppId
+        };
+    }
+
     /// <inheritdoc cref="SendAsync(string, string, Uri?, AgenticIdentity?, CancellationToken)"/>
     [Obsolete("Use SendAsync instead.")]
     public Task<SendActivityResponse?> Send(string conversationId, string text, Uri? serviceUrl = null, AgenticIdentity? agenticIdentity = null, CancellationToken cancellationToken = default)
diff --git a/core/src/Microsoft.Teams.Apps/TeamsBotApplicationOptions.cs b/core/src/Microsoft.Teams.Apps/TeamsBotApplicationOptions.cs
index 1bc1ca16..56362971 100644
--- a/core/src/Microsoft.Teams.Apps/TeamsBotApplicationOptions.cs
+++ b/core/src/Microsoft.Teams.Apps/TeamsBotApplicationOptions.cs
@@ -15,6 +15,11 @@ public sealed class TeamsBotApplicationOptions : BotApplicationOptions
 {
     internal List<OAuthFlowDescriptor> OAuthFlows { get; } = [];
 
+    /// <summary>
+    /// Gets or sets the configured tenant ID. Used as the default tenant for agentic identities created by <see cref="TeamsBotApplication.GetAgenticIdentity"/>.
+    /// </summary>
+    public string? TenantId { get; set; }
+
     /// <summary>
     /// Register an OAuth flow with the given connection name and optional configuration.
     /// </summary>
diff --git a/core/test/Microsoft.Teams.Apps.UnitTests/AgenticIdentityDefaultsTests.cs b/core/test/Microsoft.Teams.Apps.UnitTests/AgenticIdentityDefaultsTests.cs
new file mode 100644
index 00000000..c27f6668
--- /dev/null
+++ b/core/test/Microsoft.Teams.Apps.UnitTests/AgenticIdentityDefaultsTests.cs
@@ -0,0 +1,529 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.Net;
+using System.Text;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Teams.Apps.Api.Clients;
+using Microsoft.Teams.Apps.Schema;
+using Microsoft.Teams.Core;
+using Microsoft.Teams.Core.Http;
+using Microsoft.Teams.Core.Schema;
+
+namespace Microsoft.Teams.Apps.UnitTests;
+
+public class AgenticIdentityDefaultsTests
+{
+    private static readonly Uri ServiceUrl = new("https://smba.trafficmanager.net/amer/");
+
+    [Fact]
+    public async Task ContextApi_UsesRecipientAgenticIdentityAsDefault()
+    {
+        CapturingHttpMessageHandler handler = new();
+        TeamsBotApplication app = CreateApp(handler);
+        AgenticIdentity expected = DefaultIdentity();
+        Context<TeamsActivity> context = new(
+            app,
+            new TeamsActivity
+            {
+                Type = TeamsActivityTypes.Message,
+                ServiceUrl = ServiceUrl,
+                Recipient = new TeamsChannelAccount
+                {
+                    AgenticAppId = expected.AgenticAppId,
+                    AgenticUserId = expected.AgenticUserId,
+                    AgenticAppBlueprintId = expected.AgenticAppBlueprintId,
+                    TenantId = expected.TenantId
+                }
+            });
+
+        await context.Api.Conversations.GetMembersPagedAsync("conversation-id");
+
+        CapturedRequest request = Assert.Single(handler.Requests);
+        AssertIdentity(expected, request.AgenticIdentity);
+    }
+
+    [Fact]
+    public async Task ContextApi_ExplicitIdentityOverridesRecipientDefault()
+    {
+        CapturingHttpMessageHandler handler = new();
+        TeamsBotApplication app = CreateApp(handler);
+        AgenticIdentity explicitIdentity = ExplicitIdentity();
+        Context<TeamsActivity> context = new(
+            app,
+            new TeamsActivity
+            {
+                Type = TeamsActivityTypes.Message,
+                ServiceUrl = ServiceUrl,
+                Recipient = new TeamsChannelAccount
+                {
+                    AgenticAppId = "default-agentic-app-id",
+                    AgenticUserId = "default-agentic-user-id",
+                    AgenticAppBlueprintId = "default-agentic-blueprint-id",
+                    TenantId = "default-tenant-id"
+                }
+            });
+
+        await context.Api.Conversations.GetMemberByIdAsync("conversation-id", "member-id", explicitIdentity);
+
+        CapturedRequest request = Assert.Single(handler.Requests);
+        AssertIdentity(explicitIdentity, request.AgenticIdentity);
+    }
+
+    [Fact]
+    public async Task ScopedApi_ServiceUrlBoundClientsUseDefaultIdentity()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity expected = DefaultIdentity();
+        ApiClient api = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = expected
+        });
+
+        await api.Conversations.CreateAsync(new ConversationParameters());
+        await api.Conversations.GetMemberByIdAsync("conversation-id", "member-id");
+        await api.Conversations.AddReactionAsync("conversation-id", "activity-id", "like");
+        await api.Teams.GetByIdAsync("team-id");
+        await api.Meetings.GetByIdAsync("meeting-id");
+
+        Assert.Equal(5, handler.Requests.Count);
+        Assert.All(handler.Requests, request => AssertIdentity(expected, request.AgenticIdentity));
+    }
+
+    [Fact]
+    public async Task ScopedApi_ExplicitIdentityOverridesDefaultIdentity()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity explicitIdentity = ExplicitIdentity();
+        ApiClient api = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = DefaultIdentity()
+        });
+
+        await api.Meetings.GetParticipantAsync("meeting-id", "participant-id", "tenant-id", explicitIdentity);
+
+        CapturedRequest request = Assert.Single(handler.Requests);
+        AssertIdentity(explicitIdentity, request.AgenticIdentity);
+    }
+
+    [Fact]
+    public async Task ForInboundActivity_UsesServiceUrlAndRecipientAgenticIdentity()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity expected = DefaultIdentity();
+        ApiClient api = CreateApiClient(handler).ForInboundActivity(new TeamsActivity
+        {
+            ServiceUrl = ServiceUrl,
+            Recipient = new TeamsChannelAccount
+            {
+                AgenticAppId = expected.AgenticAppId,
+                AgenticUserId = expected.AgenticUserId,
+                AgenticAppBlueprintId = expected.AgenticAppBlueprintId,
+                TenantId = expected.TenantId
+            }
+        });
+
+        await api.Conversations.GetMembersPagedAsync("conversation-id");
+
+        Assert.Equal(ServiceUrl, api.ServiceUrl);
+        CapturedRequest request = Assert.Single(handler.Requests);
+        AssertIdentity(expected, request.AgenticIdentity);
+    }
+
+    [Fact]
+    public async Task ForRequestOptions_UsesServiceUrlAndAgenticIdentity()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity expected = DefaultIdentity();
+        ApiClient api = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = expected
+        });
+
+        await api.Conversations.GetMembersPagedAsync("conversation-id");
+
+        Assert.Equal(ServiceUrl, api.ServiceUrl);
+        CapturedRequest request = Assert.Single(handler.Requests);
+        AssertIdentity(expected, request.AgenticIdentity);
+    }
+
+    [Fact]
+    public void ForInboundActivity_ThrowsWhenServiceUrlIsMissing()
+    {
+        ApiClient api = CreateApiClient(new CapturingHttpMessageHandler());
+
+        InvalidOperationException exception = Assert.Throws<InvalidOperationException>(() => api.ForInboundActivity(new TeamsActivity()));
+
+        Assert.Equal("Activity.ServiceUrl is required to use the Api client.", exception.Message);
+    }
+
+    [Fact]
+    public void ForRequestOptions_ThrowsWhenServiceUrlIsMissing()
+    {
+        ApiClient api = CreateApiClient(new CapturingHttpMessageHandler());
+
+        InvalidOperationException exception = Assert.Throws<InvalidOperationException>(() => api.ForRequestOptions(new RequestOptions()));
+
+        Assert.Equal("RequestOptions.ServiceUrl is required to scope the Api client.", exception.Message);
+    }
+
+    [Fact]
+    public async Task ConversationApi_ActivityMethodsUseDefaultIdentityWhenExplicitIdentityIsMissing()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity expected = DefaultIdentity();
+        ConversationApiClient conversations = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = expected
+        }).Conversations;
+
+        await conversations.CreateActivityAsync("conversation-id", CreateActivity());
+        await conversations.UpdateActivityAsync("conversation-id", "activity-id", CreateActivity());
+        await conversations.ReplyToActivityAsync("conversation-id", "activity-id", CreateActivity());
+        await conversations.DeleteActivityAsync("conversation-id", "activity-id");
+        await conversations.GetActivityMembersAsync("conversation-id", "activity-id");
+        await conversations.CreateTargetedActivityAsync("conversation-id", CreateTargetedActivity());
+        await conversations.UpdateTargetedActivityAsync("conversation-id", "activity-id", CreateActivity());
+        await conversations.DeleteTargetedActivityAsync("conversation-id", "activity-id");
+
+        Assert.Equal(8, handler.Requests.Count);
+        Assert.All(handler.Requests, request => AssertIdentity(expected, request.AgenticIdentity));
+    }
+
+    [Fact]
+    public async Task ConversationApi_ActivityMethodsExplicitIdentityOverridesDefaultIdentity()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity explicitIdentity = ExplicitIdentity();
+        ConversationApiClient conversations = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = DefaultIdentity()
+        }).Conversations;
+        RequestOptions options = CreateRequestOptions(explicitIdentity);
+
+        await conversations.CreateActivityAsync("conversation-id", CreateActivity(), options);
+        await conversations.UpdateActivityAsync("conversation-id", "activity-id", CreateActivity(), options);
+        await conversations.ReplyToActivityAsync("conversation-id", "activity-id", CreateActivity(), options);
+        await conversations.DeleteActivityAsync("conversation-id", "activity-id", options);
+        await conversations.GetActivityMembersAsync("conversation-id", "activity-id", options);
+        await conversations.CreateTargetedActivityAsync("conversation-id", CreateTargetedActivity(), options);
+        await conversations.UpdateTargetedActivityAsync("conversation-id", "activity-id", CreateActivity(), options);
+        await conversations.DeleteTargetedActivityAsync("conversation-id", "activity-id", options);
+
+        Assert.Equal(8, handler.Requests.Count);
+        Assert.All(handler.Requests, request => AssertIdentity(explicitIdentity, request.AgenticIdentity));
+    }
+
+    [Fact]
+    public async Task ConversationApi_ActivityFromIdentityOverridesFallbackIdentity()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity fromIdentity = new()
+        {
+            AgenticAppId = "from-agentic-app-id",
+            AgenticUserId = "from-agentic-user-id",
+            AgenticAppBlueprintId = "from-agentic-blueprint-id",
+            TenantId = "from-tenant-id"
+        };
+        ConversationApiClient conversations = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = DefaultIdentity()
+        }).Conversations;
+        RequestOptions options = CreateRequestOptions(ExplicitIdentity());
+
+        await conversations.CreateActivityAsync("conversation-id", CreateActivity(fromIdentity), options);
+        await conversations.UpdateActivityAsync("conversation-id", "activity-id", CreateActivity(fromIdentity), options);
+
+        Assert.Equal(2, handler.Requests.Count);
+        Assert.All(handler.Requests, request =>
+        {
+            AssertIdentity(fromIdentity, request.AgenticIdentity);
+            Assert.Equal("from-bot-id", request.BotAppId);
+        });
+    }
+
+    [Fact]
+    public async Task ConversationApi_ActivityRequestOptionsServiceUrlOverridesScopedServiceUrl()
+    {
+        CapturingHttpMessageHandler handler = new();
+        Uri serviceUrl = new("https://override.example.com/");
+        ConversationApiClient conversations = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = DefaultIdentity()
+        }).Conversations;
+
+        await conversations.CreateActivityAsync("conversation-id", CreateActivity(), new RequestOptions { ServiceUrl = serviceUrl });
+
+        CapturedRequest request = Assert.Single(handler.Requests);
+        Assert.StartsWith(serviceUrl.ToString(), request.Url, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public async Task ActivityClient_UsesDefaultIdentityWhenExplicitIdentityIsMissing()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity expected = DefaultIdentity();
+#pragma warning disable CS0618 // Verifies backward-compatible obsolete wrapper behavior.
+        ActivityClient activities = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = expected
+        }).Conversations.Activities;
+#pragma warning restore CS0618
+
+        await activities.CreateAsync("conversation-id", CreateActivity());
+        await activities.UpdateAsync("conversation-id", "activity-id", CreateActivity());
+        await activities.ReplyAsync("conversation-id", "activity-id", CreateActivity());
+        await activities.DeleteAsync("conversation-id", "activity-id");
+        await activities.GetMembersAsync("conversation-id", "activity-id");
+        await activities.CreateTargetedAsync("conversation-id", CreateTargetedActivity());
+        await activities.UpdateTargetedAsync("conversation-id", "activity-id", CreateActivity());
+        await activities.DeleteTargetedAsync("conversation-id", "activity-id");
+
+        Assert.Equal(8, handler.Requests.Count);
+        Assert.All(handler.Requests, request => AssertIdentity(expected, request.AgenticIdentity));
+    }
+
+    [Fact]
+    public async Task ActivityClient_ExplicitIdentityOverridesDefaultIdentity()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity explicitIdentity = ExplicitIdentity();
+#pragma warning disable CS0618 // Verifies backward-compatible obsolete wrapper behavior.
+        ActivityClient activities = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = DefaultIdentity()
+        }).Conversations.Activities;
+#pragma warning restore CS0618
+        RequestOptions options = CreateRequestOptions(explicitIdentity);
+
+        await activities.CreateAsync("conversation-id", CreateActivity(), options);
+        await activities.UpdateAsync("conversation-id", "activity-id", CreateActivity(), options);
+        await activities.ReplyAsync("conversation-id", "activity-id", CreateActivity(), options);
+        await activities.DeleteAsync("conversation-id", "activity-id", options);
+        await activities.GetMembersAsync("conversation-id", "activity-id", options);
+        await activities.CreateTargetedAsync("conversation-id", CreateTargetedActivity(), options);
+        await activities.UpdateTargetedAsync("conversation-id", "activity-id", CreateActivity(), options);
+        await activities.DeleteTargetedAsync("conversation-id", "activity-id", options);
+
+        Assert.Equal(8, handler.Requests.Count);
+        Assert.All(handler.Requests, request => AssertIdentity(explicitIdentity, request.AgenticIdentity));
+    }
+
+    [Fact]
+    public async Task ActivityClient_ActivityFromIdentityOverridesFallbackIdentity()
+    {
+        CapturingHttpMessageHandler handler = new();
+        AgenticIdentity fromIdentity = new()
+        {
+            AgenticAppId = "from-agentic-app-id",
+            AgenticUserId = "from-agentic-user-id",
+            AgenticAppBlueprintId = "from-agentic-blueprint-id",
+            TenantId = "from-tenant-id"
+        };
+#pragma warning disable CS0618 // Verifies backward-compatible obsolete wrapper behavior.
+        ActivityClient activities = CreateApiClient(handler).ForRequestOptions(new RequestOptions
+        {
+            ServiceUrl = ServiceUrl,
+            AgenticIdentity = DefaultIdentity()
+        }).Conversations.Activities;
+#pragma warning restore CS0618
+        RequestOptions options = CreateRequestOptions(ExplicitIdentity());
+
+        await activities.CreateAsync("conversation-id", CreateActivity(fromIdentity), options);
+        await activities.UpdateAsync("conversation-id", "activity-id", CreateActivity(fromIdentity), options);
+
+        Assert.Equal(2, handler.Requests.Count);
+        Assert.All(handler.Requests, request =>
+        {
+            AssertIdentity(fromIdentity, request.AgenticIdentity);
+            Assert.Equal("from-bot-id", request.BotAppId);
+        });
+    }
+
+    [Fact]
+    public void GetAgenticIdentity_DefaultsBlueprintAndTenant()
+    {
+        TeamsBotApplication app = CreateApp(options: new TeamsBotApplicationOptions
+        {
+            AppId = "app-id",
+            TenantId = "tenant-id"
+        });
+
+        AgenticIdentity identity = app.GetAgenticIdentity("agentic-app-id", "agentic-user-id");
+
+        Assert.Equal("agentic-app-id", identity.AgenticAppId);
+        Assert.Equal("agentic-user-id", identity.AgenticUserId);
+        Assert.Equal("app-id", identity.AgenticAppBlueprintId);
+        Assert.Equal("tenant-id", identity.TenantId);
+    }
+
+    [Fact]
+    public void GetAgenticIdentity_ExplicitValuesOverrideDefaults()
+    {
+        TeamsBotApplication app = CreateApp(options: new TeamsBotApplicationOptions
+        {
+            AppId = "app-id",
+            TenantId = "tenant-id"
+        });
+
+        AgenticIdentity identity = app.GetAgenticIdentity(
+            "agentic-app-id",
+            "agentic-user-id",
+            tenantId: "explicit-tenant-id",
+            agenticAppBlueprintId: "explicit-blueprint-id");
+
+        Assert.Equal("explicit-blueprint-id", identity.AgenticAppBlueprintId);
+        Assert.Equal("explicit-tenant-id", identity.TenantId);
+    }
+
+    [Fact]
+    public void GetAgenticIdentity_LeavesTenantNullWhenUnconfigured()
+    {
+        TeamsBotApplication app = CreateApp(options: new TeamsBotApplicationOptions { AppId = "app-id" });
+
+        AgenticIdentity identity = app.GetAgenticIdentity("agentic-app-id", "agentic-user-id");
+
+        Assert.Equal("app-id", identity.AgenticAppBlueprintId);
+        Assert.Null(identity.TenantId);
+    }
+
+    private static TeamsBotApplication CreateApp(CapturingHttpMessageHandler? handler = null, TeamsBotApplicationOptions? options = null)
+        => new(
+            CreateApiClient(handler ?? new CapturingHttpMessageHandler()),
+            new HttpContextAccessor(),
+            NullLogger<TeamsBotApplication>.Instance,
+            options ?? new TeamsBotApplicationOptions { AppId = "app-id" });
+
+    private static ApiClient CreateApiClient(CapturingHttpMessageHandler handler)
+    {
+        HttpClient httpClient = new(handler);
+        ConversationClient conversationClient = new(httpClient, NullLogger<ConversationClient>.Instance);
+        UserTokenClient userTokenClient = new(new HttpClient(), new ConfigurationBuilder().Build(), NullLogger<UserTokenClient>.Instance);
+        return new ApiClient(httpClient, conversationClient, userTokenClient);
+    }
+
+    private static CoreActivity CreateActivity(AgenticIdentity? fromIdentity = null)
+    {
+        CoreActivity activity = new()
+        {
+            Type = ActivityType.Message
+        };
+
+        if (fromIdentity is not null)
+        {
+            activity.From = new ChannelAccount
+            {
+                Id = "28:from-bot-id",
+                AgenticAppId = fromIdentity.AgenticAppId,
+                AgenticUserId = fromIdentity.AgenticUserId,
+                AgenticAppBlueprintId = fromIdentity.AgenticAppBlueprintId,
+                TenantId = fromIdentity.TenantId
+            };
+        }
+
+        return activity;
+    }
+
+    private static CoreActivity CreateTargetedActivity()
+        => new()
+        {
+            Type = ActivityType.Message,
+            Recipient = new ChannelAccount { Id = "recipient-id" }
+        };
+
+    private static AgenticIdentity DefaultIdentity()
+        => new()
+        {
+            AgenticAppId = "default-agentic-app-id",
+            AgenticUserId = "default-agentic-user-id",
+            AgenticAppBlueprintId = "default-agentic-blueprint-id",
+            TenantId = "default-tenant-id"
+        };
+
+    private static AgenticIdentity ExplicitIdentity()
+        => new()
+        {
+            AgenticAppId = "explicit-agentic-app-id",
+            AgenticUserId = "explicit-agentic-user-id",
+            AgenticAppBlueprintId = "explicit-agentic-blueprint-id",
+            TenantId = "explicit-tenant-id"
+        };
+
+    private static RequestOptions CreateRequestOptions(AgenticIdentity agenticIdentity)
+        => new() { AgenticIdentity = agenticIdentity };
+
+    private static void AssertIdentity(AgenticIdentity expected, AgenticIdentity? actual)
+    {
+        Assert.NotNull(actual);
+        Assert.Equal(expected.AgenticAppId, actual!.AgenticAppId);
+        Assert.Equal(expected.AgenticUserId, actual.AgenticUserId);
+        Assert.Equal(expected.AgenticAppBlueprintId, actual.AgenticAppBlueprintId);
+        Assert.Equal(expected.TenantId, actual.TenantId);
+    }
+
+    private sealed class CapturingHttpMessageHandler : HttpMessageHandler
+    {
+        private static readonly HttpRequestOptionsKey<object?> AgenticIdentityKey = new(BotRequestContext.AgenticIdentityKey);
+        private static readonly HttpRequestOptionsKey<object?> BotAppIdKey = new(BotRequestContext.BotAppIdKey);
+
+        public List<CapturedRequest> Requests { get; } = [];
+
+        protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            request.Options.TryGetValue(AgenticIdentityKey, out object? agenticIdentity);
+            request.Options.TryGetValue(BotAppIdKey, out object? botAppId);
+            Requests.Add(new CapturedRequest(
+                request.Method,
+                request.RequestUri?.ToString() ?? string.Empty,
+                agenticIdentity as AgenticIdentity,
+                botAppId as string));
+
+            return Task.FromResult(CreateResponse(request));
+        }
+
+        private static HttpResponseMessage CreateResponse(HttpRequestMessage request)
+        {
+            string path = request.RequestUri?.AbsolutePath ?? string.Empty;
+            string json = path.Contains("/pagedmembers", StringComparison.Ordinal)
+                ? "{\"members\":[{\"id\":\"member-id\"}]}"
+                : path.EndsWith("/members", StringComparison.Ordinal)
+                    ? "[{\"id\":\"member-id\"}]"
+                    : path.Contains("/members/", StringComparison.Ordinal)
+                        ? "{\"id\":\"member-id\"}"
+                        : path.EndsWith("/conversations", StringComparison.Ordinal) && request.Method == HttpMethod.Post
+                            ? "{\"id\":\"conversation-id\"}"
+                            : path.Contains("/activities", StringComparison.Ordinal) && request.Method != HttpMethod.Delete
+                                ? "{\"id\":\"activity-id\"}"
+                                : path.Contains("/teams/", StringComparison.Ordinal) && path.EndsWith("/conversations", StringComparison.Ordinal)
+                                    ? "{\"conversations\":[]}"
+                                    : path.Contains("/teams/", StringComparison.Ordinal)
+                                        ? "{\"id\":\"team-id\"}"
+                                        : path.Contains("/meetings/", StringComparison.Ordinal) && path.Contains("/participants/", StringComparison.Ordinal)
+                                            ? "{\"user\":{\"id\":\"participant-id\"}}"
+                                            : path.Contains("/meetings/", StringComparison.Ordinal)
+                                                ? "{\"id\":\"meeting-id\"}"
+                                                : string.Empty;
+
+            HttpResponseMessage response = new(HttpStatusCode.OK);
+            if (json.Length > 0)
+            {
+                response.Content = new StringContent(json, Encoding.UTF8, "application/json");
+            }
+
+            return response;
+        }
+    }
+
+    private sealed record CapturedRequest(HttpMethod Method, string Url, AgenticIdentity? AgenticIdentity, string? BotAppId);
+}
diff --git a/core/test/Microsoft.Teams.Apps.UnitTests/TeamsBotApplicationHostingExtensionsTests.cs b/core/test/Microsoft.Teams.Apps.UnitTests/TeamsBotApplicationHostingExtensionsTests.cs
index 7acabc0d..9369c813 100644
--- a/core/test/Microsoft.Teams.Apps.UnitTests/TeamsBotApplicationHostingExtensionsTests.cs
+++ b/core/test/Microsoft.Teams.Apps.UnitTests/TeamsBotApplicationHostingExtensionsTests.cs
@@ -42,6 +42,7 @@ public void AddTeamsBotApplication_RegistersAllRequiredServices()
         Assert.NotNull(serviceProvider.GetRequiredService<IHttpContextAccessor>());
         TeamsBotApplicationOptions options = serviceProvider.GetRequiredService<TeamsBotApplicationOptions>();
         Assert.Equal("teams-bundle-client-id", options.AppId);
+        Assert.Equal("teams-bundle-tenant-id", options.TenantId);
 
         BotApplicationOptions botOptions = serviceProvider.GetRequiredService<BotApplicationOptions>();
         Assert.Equal("teams-bundle-client-id", botOptions.AppId);