Remove enable http preproccessor blocks (#3437)

* Remove ENABLE_HTTP preprocessor blocks

* Update comment in New-BuildInfo.ps1

* Fix typo

Directory.Build.props

@@ -28,16 +28,6 @@
     <DefineConstants>$(DefineConstants);BUILD_NATIVE</DefineConstants>
   </PropertyGroup>
 
-    <!-- We're using a prerelease version of IdWeb with trimmer support, which enables HTTP support for
-      trimmed azmcp builds across all distributions. The ENABLE_HTTP flag provides a rollback mechanism:
-      if we need to revert to an IdWeb version without trimmer support, we can disable HTTP accordingly.
-      Eventually, ENABLE_HTTP directives will be removed from the code as IdWeb's trimmer support moves
-      closer to GA.
-      See https://github.com/microsoft/mcp/issues/1764 -->
-  <PropertyGroup>
-    <DefineConstants>$(DefineConstants);ENABLE_HTTP</DefineConstants>
-  </PropertyGroup>
-
     <!-- Windows AOT native build security flags to enable 'Control Flow Guard' (CFG) -->
   <PropertyGroup Condition="'$(BuildNative)' == 'true' and $(RuntimeIdentifier.StartsWith('win'))">
     <ControlFlowGuard>Guard</ControlFlowGuard>

core/Microsoft.Mcp.Core/src/Areas/Server/Commands/ServerStartCommand.cs

@@ -218,8 +218,7 @@ public sealed class ServerStartCommand : BaseCommand<ServerStartOptions, string>
 
     /// <summary>
     /// Validates the transport configuration, ensuring the transport type is valid and compatible with other options.
-    /// Verifies that HTTP transport is only used when available (ENABLE_HTTP), and that --dangerously-disable-http-incoming-auth
-    /// is only specified with HTTP transport.
+    /// Verifies that --dangerously-disable-http-incoming-auth is only specified with HTTP transport.
     /// </summary>
     /// <param name="options">The bound ServerStartOptions.</param>
     /// <param name="validationResult">Validation result to update on failure.</param>
@@ -236,12 +235,7 @@ public sealed class ServerStartCommand : BaseCommand<ServerStartOptions, string>
 
         if (options.Transport == TransportTypes.Http)
         {
-#if ENABLE_HTTP
             return;
-#else
-            validationResult.Errors.Add($"{TransportTypes.Http} transport is only supported in the Docker image distribution of Azure MCP Server. Please use the Docker image or switch to {TransportTypes.StdIo} transport.");
-            return;
-#endif
         }
 
         validationResult.Errors.Add($"Invalid transport '{options.Transport}'. Valid transports are: {TransportTypes.StdIo}, {TransportTypes.Http}.");
@@ -272,16 +266,11 @@ public sealed class ServerStartCommand : BaseCommand<ServerStartOptions, string>
     {
         if (options.OutgoingAuthStrategy == OutgoingAuthStrategy.UseOnBehalfOf)
         {
-#if ENABLE_HTTP
             if (options.Transport != TransportTypes.Http || options.DangerouslyDisableHttpIncomingAuth)
             {
                 validationResult.Errors.Add($"The {OutgoingAuthStrategy.UseOnBehalfOf} outgoing authentication strategy requires the server to run in authenticated HTTP mode (--transport http without --dangerously-disable-http-incoming-auth).");
             }
             return;
-#else
-            validationResult.Errors.Add($"{OutgoingAuthStrategy.UseOnBehalfOf} outgoing authentication strategy is only supported in the Docker image distribution of Azure MCP Server. " +
-                "Please use the Docker image or switch to a different outgoing authentication strategy.");
-#endif
         }
     }
 
@@ -316,7 +305,6 @@ public sealed class ServerStartCommand : BaseCommand<ServerStartOptions, string>
         // that require a user-facing terminal (e.g. DeviceCodeCredential) can refuse to activate.
         CustomChainedCredential.ActiveTransport = serverOptions.Transport;
 
-#if ENABLE_HTTP
         if (serverOptions.Transport == TransportTypes.Http)
         {
             if (serverOptions.DangerouslyDisableHttpIncomingAuth)
@@ -332,9 +320,6 @@ public sealed class ServerStartCommand : BaseCommand<ServerStartOptions, string>
         {
             return CreateStdioHost(serverOptions);
         }
-#else
-        return CreateStdioHost(serverOptions);
-#endif
     }
 
     /// <summary>
@@ -880,7 +865,6 @@ public sealed class ServerStartCommand : BaseCommand<ServerStartOptions, string>
     /// <returns>The resolved OutgoingAuthStrategy.</returns>
     private static OutgoingAuthStrategy ResolveAuthStrategy(ServerStartOptions options)
     {
-#if ENABLE_HTTP
         if (options.OutgoingAuthStrategy == OutgoingAuthStrategy.NotSet)
         {
             if (options.Transport == TransportTypes.Http)
@@ -895,9 +879,6 @@ public sealed class ServerStartCommand : BaseCommand<ServerStartOptions, string>
             }
         }
         return options.OutgoingAuthStrategy;
-#else
-        return OutgoingAuthStrategy.UseHostingEnvironmentIdentity;
-#endif
     }
 
     private static WebApplication UseHttpsRedirectionIfEnabled(WebApplication app)

eng/scripts/New-BuildInfo.ps1

@@ -37,14 +37,9 @@ $excludedPlatforms = @(
 # Platforms outside of the standard combinations that should also be built.  Setting a "specialPurpose" allows then to
 # be targeted or excluded in packaging scripts
 $additionalPlatforms = @(
-    # We currently use a prerelease version of Microsoft.Identity.Web with AOT-safe HTTP support,
-    # which allows shipping trimmed azmcp with http across all distributions (including Docker). 
-    # Previously, Docker was shipped untrimmed to enable http support, while only other distributions
-    # where trimmed without HTTP support. These additional Docker platforms are retained as a rollback safety net
-    # in case we need to revert to the non-prerelease version and limit HTTP support to Docker only.
-    # Once Microsoft.Identity.Web with AOT support reaches GA, additionalPlatforms should be removed
-    # and Docker builds should use the standard platform definitions.
-    # https://github.com/microsoft/mcp/issues/1764
+    # Add additional builds for Docker as they use the musl runtime variant which differs from the default Linux builds.
+    # In the future we can evaluate if these can be moved to the standard Linux builds to remove two jobs from our
+    # standard pipeline.
     @{
         name            = 'linux-musl-x64-docker'
         operatingSystem = 'linux'