diff --git a/AyCode.Core/Serializers/Binaries/AcBinaryDeserializer.cs b/AyCode.Core/Serializers/Binaries/AcBinaryDeserializer.cs
index 209cf47..dabbfd5 100644
--- a/AyCode.Core/Serializers/Binaries/AcBinaryDeserializer.cs
+++ b/AyCode.Core/Serializers/Binaries/AcBinaryDeserializer.cs
@@ -5,7 +5,6 @@ using System.Collections.Concurrent;
 using System.Collections.Frozen;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using System.IO.Pipelines;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.CompilerServices;
@@ -375,57 +374,6 @@ public static partial class AcBinaryDeserializer
         }
     }
 
-    /// <summary>
-    /// Drains a <see cref="PipeReader"/> end-to-end into a fresh <see cref="AsyncPipeReaderInput"/>
-    /// and deserializes one message. Background <c>Task.Run</c> deserializes incrementally while
-    /// the calling thread drains the reader. For long-lived multi-message scenarios use the
-    /// <see cref="AsyncPipeReaderInput"/> overloads directly.
-    /// </summary>
-    public static async Task<T?> DeserializeFromPipeReaderAsync<[DynamicallyAccessedMembers(TypeMetadataBase.RequiredMembers)] T>(PipeReader reader, AcBinarySerializerOptions options, CancellationToken cancellationToken = default)
-    {
-        if (reader is null) throw new ArgumentNullException(nameof(reader));
-        using var input = new AsyncPipeReaderInput(options.BufferWriterChunkSize * 2);
-        var deserTask = Task.Run(() => Deserialize<T>(input, options), cancellationToken);
-        await DrainPipeReaderToInputAsync(reader, input, cancellationToken).ConfigureAwait(false);
-        return await deserTask.ConfigureAwait(false);
-    }
-
-    /// <summary>
-    /// Non-generic <c>Type</c>-based counterpart to <see cref="DeserializeFromPipeReaderAsync{T}"/>.
-    /// For runtime-typed scenarios (MVC formatters, plugin frameworks).
-    /// </summary>
-    public static async Task<object?> DeserializeFromPipeReaderAsync(PipeReader reader, [DynamicallyAccessedMembers(TypeMetadataBase.RequiredMembers)] Type targetType, AcBinarySerializerOptions options, CancellationToken cancellationToken = default)
-    {
-        if (reader is null) throw new ArgumentNullException(nameof(reader));
-        using var input = new AsyncPipeReaderInput(options.BufferWriterChunkSize * 2);
-        var deserTask = Task.Run(() => Deserialize(input, targetType, options), cancellationToken);
-        await DrainPipeReaderToInputAsync(reader, input, cancellationToken).ConfigureAwait(false);
-        return await deserTask.ConfigureAwait(false);
-    }
-
-    /// <summary>
-    /// Pumps a <see cref="PipeReader"/> into a <see cref="AsyncPipeReaderInput"/> via repeated
-    /// <see cref="AsyncPipeReaderInput.Feed"/> calls; signals <see cref="AsyncPipeReaderInput.Complete"/>
-    /// at end-of-stream (in finally so consumer always wakes up on cancellation / exception).
-    /// </summary>
-    private static async Task DrainPipeReaderToInputAsync(PipeReader reader, AsyncPipeReaderInput input, CancellationToken cancellationToken)
-    {
-        try
-        {
-            while (true)
-            {
-                var result = await reader.ReadAsync(cancellationToken).ConfigureAwait(false);
-                foreach (var segment in result.Buffer) input.Feed(segment.Span);
-                reader.AdvanceTo(result.Buffer.End);
-                if (result.IsCompleted) break;
-            }
-        }
-        finally
-        {
-            input.Complete();
-        }
-    }
-
     /// <summary>
     /// Internal: Deserialize with any TInput (multi-segment or other future input types).
     /// </summary>
diff --git a/AyCode.Core/docs/BINARY/BINARY_TODO.md b/AyCode.Core/docs/BINARY/BINARY_TODO.md
index c9e9a0a..d9b71fb 100644
--- a/AyCode.Core/docs/BINARY/BINARY_TODO.md
+++ b/AyCode.Core/docs/BINARY/BINARY_TODO.md
@@ -371,13 +371,11 @@ Added in `AcBinarySerializer.cs`:
 - `SerializeChunked(object?, Type, PipeWriter, opts)` → `int`
 - `SerializeChunkedFramed(object?, Type, PipeWriter, opts)` → `int`
 
-Added in `AcBinaryDeserializer.cs`:
-- `DeserializeFromPipeReaderAsync<T>(PipeReader, opts, ct)` → `Task<T?>`
-- `DeserializeFromPipeReaderAsync(PipeReader, Type, opts, ct)` → `Task<object?>`
+`AcBinaryDeserializer.cs` already had `Deserialize(byte[], Type, opts)` / `Deserialize(ReadOnlySequence<byte>, Type, opts)` / `Deserialize(AsyncPipeReaderInput, Type, opts)` overloads — no new entries needed.
 
-The `Deserialize(byte[], Type, opts)` / `Deserialize(ReadOnlySequence<byte>, Type, opts)` / `Deserialize(AsyncPipeReaderInput, Type, opts)` overloads already existed.
+**Layering note**: `PipeReader → AsyncPipeReaderInput` drain-loop is the consumer's responsibility, not the binary serializer's. The serializer surface ends at `AsyncPipeReaderInput`; transport-specific draining (PipeReader, NamedPipe, SignalR `state.Buffer.Write`, etc.) lives in the consumer layer (e.g. `AcBinaryInputFormatter`, `AcBinaryHubProtocol.TryParseChunkData`).
 
-Consumed by ASP.NET Core MVC formatter package (`AyCode.Services/Mvc/`) — `AcBinaryInputFormatter`, `AcBinaryOutputFormatter`, `AddAcBinaryFormatters` extension. Media type: `application/vnd.acbinary`.
+Consumed by ASP.NET Core MVC formatter package (`AyCode.Services/Mvc/`) — `AcBinaryInputFormatter`, `AcBinaryOutputFormatter`, `AddAcBinaryFormatters` extension. Media type: `application/vnd.acbinary`. Drain-loop inlined in `AcBinaryInputFormatter.ReadRequestBodyAsync`.
 
 Plugin frameworks, ASP.NET ModelBinding, DI middleware, and DataContractSerializer-style "generic-API container" use-cases need to serialize an `object` whose type is known only at runtime. Current AcBinary surface forces a reflection trampoline through the generic `Serialize<T>`:
 
diff --git a/AyCode.Services/Mvc/AcBinaryInputFormatter.cs b/AyCode.Services/Mvc/AcBinaryInputFormatter.cs
index c068bda..1daf837 100644
--- a/AyCode.Services/Mvc/AcBinaryInputFormatter.cs
+++ b/AyCode.Services/Mvc/AcBinaryInputFormatter.cs
@@ -7,8 +7,9 @@ namespace AyCode.Services.Mvc;
 
 /// <summary>
 /// ASP.NET Core MVC InputFormatter for AcBinary wire format. Reads request body via PipeReader,
-/// drains into AsyncPipeReaderInput, deserializes to ModelType. Standard ProblemDetails error
-/// flow on failure (ModelState.AddModelError → 400 + application/problem+json).
+/// drains chunks into AsyncPipeReaderInput on the calling thread while a background task
+/// deserializes incrementally, then returns the result. Standard ProblemDetails error flow on
+/// failure (ModelState.AddModelError → 400 + application/problem+json).
 /// </summary>
 public class AcBinaryInputFormatter : InputFormatter
 {
@@ -31,9 +32,28 @@ public class AcBinaryInputFormatter : InputFormatter
 
         var ct = context.HttpContext.RequestAborted;
         var reader = PipeReader.Create(context.HttpContext.Request.Body);
+
         try
         {
-            var model = await AcBinaryDeserializer.DeserializeFromPipeReaderAsync(reader, context.ModelType, _options, ct).ConfigureAwait(false);
+            using var input = new AsyncPipeReaderInput(_options.BufferWriterChunkSize * 2);
+            var deserTask = Task.Run(() => AcBinaryDeserializer.Deserialize(input, context.ModelType, _options), ct);
+
+            try
+            {
+                while (true)
+                {
+                    var result = await reader.ReadAsync(ct).ConfigureAwait(false);
+                    foreach (var segment in result.Buffer) input.Feed(segment.Span);
+                    reader.AdvanceTo(result.Buffer.End);
+                    if (result.IsCompleted) break;
+                }
+            }
+            finally
+            {
+                input.Complete();
+            }
+
+            var model = await deserTask.ConfigureAwait(false);
             return await InputFormatterResult.SuccessAsync(model).ConfigureAwait(false);
         }
         catch (OperationCanceledException) when (ct.IsCancellationRequested)