diff --git a/src/jvm/com/tjclp/scalagent/a2a/A2AServerLive.scala b/src/jvm/com/tjclp/scalagent/a2a/A2AServerLive.scala
index d129fef..dc9a7bc 100644
--- a/src/jvm/com/tjclp/scalagent/a2a/A2AServerLive.scala
+++ b/src/jvm/com/tjclp/scalagent/a2a/A2AServerLive.scala
@@ -136,7 +136,16 @@ private[a2a] final class A2AServerLiveImpl(
       scope <- Scope.make
       _     <-
         (for
-          serverEnv <- (ZLayer.succeed(Server.Config.default.binding(config.host, config.port)) >>> Server.live)
+          // zio-http's Server.Config.default caps request bodies at 100 KiB
+          // (RequestStreaming.Disabled(1024*100)); A2A messages carry base64
+          // file uploads that exceed that, so apply the configured limit or
+          // they'd 413. disableRequestStreaming keeps full-body aggregation
+          // (the routes parse the whole JSON-RPC body) with the larger cap.
+          serverEnv <- (ZLayer.succeed(
+                         Server.Config.default
+                           .binding(config.host, config.port)
+                           .disableRequestStreaming(config.maxRequestBodyBytes)
+                       ) >>> Server.live)
             .build(scope)
           _ <- Server.install(a2aRoutes).provideEnvironment(serverEnv)
           _ <- startGrpcServer
diff --git a/src/shared/com/tjclp/scalagent/a2a/A2AServerDefaults.scala b/src/shared/com/tjclp/scalagent/a2a/A2AServerDefaults.scala
index 8883280..9182460 100644
--- a/src/shared/com/tjclp/scalagent/a2a/A2AServerDefaults.scala
+++ b/src/shared/com/tjclp/scalagent/a2a/A2AServerDefaults.scala
@@ -10,7 +10,10 @@ object A2AServerDefaults:
   val EventReplayLimit: Int                    = 1000
   val EventStoreAppendTimeout: Duration        = 2.seconds
   val EventStoreLoadTimeout: Duration          = 5.seconds
-  val MaxRequestBodyBytes: Int                 = 1024 * 1024
+  // A2A messages carry file uploads as base64 inside the JSON-RPC body
+  // (~33% inflation), so this must comfortably exceed the largest raw
+  // upload a client allows. 64 MiB covers rtalk's 32 MB raw cap encoded.
+  val MaxRequestBodyBytes: Int                 = 64 * 1024 * 1024
   val PushNotificationPostTimeout: Duration    = 20.seconds
   val PushNotificationMaxRetries: Int          = 2
   val PushNotificationRetryBaseDelay: Duration = 250.millis
diff --git a/test/js/com/tjclp/scalagent/a2a/A2ARestTransportSpec.scala b/test/js/com/tjclp/scalagent/a2a/A2ARestTransportSpec.scala
index 86feb00..2990a47 100644
--- a/test/js/com/tjclp/scalagent/a2a/A2ARestTransportSpec.scala
+++ b/test/js/com/tjclp/scalagent/a2a/A2ARestTransportSpec.scala
@@ -552,6 +552,44 @@ class A2ARestTransportSpec extends FunSuite:
       assert(response.error.exists(_.message.contains("Request body exceeds 8 byte limit")))
     }
 
+  // Parity with the JVM #58 fix: the JS server enforces maxRequestBodyBytes in
+  // readBodyLimited (not via a framework default), so the raised 64 MiB shared
+  // default must let it accept the same large inline uploads. Uses the default
+  // limit (no override) and a body well above zio-http's old 100 KiB cap.
+  test("accepts message/send bodies larger than the old 100 KiB cap with the default limit"):
+    val config = A2AServer.Config(
+      name = "LargeBodyTest",
+      description = "Large body test server",
+      host = "127.0.0.1",
+      port = 0,
+      executionOverride = Some(completedExecution),
+    )
+    // ~200 KiB: above zio-http's old 100 KiB cap, well below the 64 MiB default.
+    val request = A2ARequest
+      .MessageSend(A2AMessage.userText("x" * (200 * 1024)), configuration = Some(MessageSendConfiguration.default))
+      .toJson
+    val headers = Map(
+      "Content-Type" -> A2AContentType.A2AJson,
+      A2AHeader.Version -> A2AProtocol.Version,
+    )
+
+    val program =
+      ZIO.scoped {
+        for
+          server <- A2AServer.create(config)
+          sent   <- fetchText(server.url + "/message:send", method = "POST", body = Some(request), headers = headers)
+          result <- ZIO.fromEither(sent._3.fromJson[A2AResponse.SendMessageResult].left.map(new RuntimeException(_)))
+          task = result match
+            case A2AResponse.SendMessageResult.TaskResult(task) => task
+            case other                                          => throw new RuntimeException(s"Expected task, got $other")
+        yield (sent._1, task)
+      }
+
+    runTask(program).map { case (status, task) =>
+      assertEquals(status, 200)
+      assertEquals(task.status.state, TaskState.Completed)
+    }
+
   test("REST errors use google.rpc-style bodies"):
     val config = A2AServer.Config(
       name = "RestErrorTest",
diff --git a/test/jvm/com/tjclp/scalagent/a2a/A2AServerLiveSpec.scala b/test/jvm/com/tjclp/scalagent/a2a/A2AServerLiveSpec.scala
index c92ae30..549aacf 100644
--- a/test/jvm/com/tjclp/scalagent/a2a/A2AServerLiveSpec.scala
+++ b/test/jvm/com/tjclp/scalagent/a2a/A2AServerLiveSpec.scala
@@ -59,6 +59,17 @@ class A2AServerLiveSpec extends FunSuite:
       response.statusCode() -> response.body()
     }
 
+  private def post(url: String, body: String, requestHeaders: Map[String, String]): Task[(Int, String)] =
+    ZIO.attemptBlocking {
+      val builder = HttpRequest
+        .newBuilder(URI.create(url))
+        .timeout(JavaDuration.ofSeconds(10))
+        .POST(HttpRequest.BodyPublishers.ofString(body))
+      requestHeaders.foreach { case (name, value) => builder.header(name, value) }
+      val response = client.send(builder.build(), HttpResponse.BodyHandlers.ofString())
+      response.statusCode() -> response.body()
+    }
+
   private def grpcStreamingResponse(
     port: Int,
     message: A2AMessage,
@@ -688,6 +699,49 @@ class A2AServerLiveSpec extends FunSuite:
       assert(response.error.exists(_.message.contains("Request body exceeds 8 byte limit")))
     }
 
+  // Regression for #58: zio-http's Server.Config.default caps request streaming at
+  // 100 KiB, so unless config.maxRequestBodyBytes is wired into the server the bound
+  // server 413s on larger bodies (e.g. base64 file uploads) before the handler runs.
+  // The handleHttp-based body-limit test above bypasses the Server.Config cap, so this
+  // exercises a real bound zio-http server end to end.
+  test("JVM bound server accepts JSON-RPC bodies larger than zio-http's default 100 KiB cap"):
+    // ~200 KiB: above zio-http's 100 KiB default, well below the 64 MiB configured limit.
+    val largeText = "x" * (200 * 1024)
+    val body = rpc(
+      A2AMethod.MessageSend,
+      A2ARequest.MessageSend(A2AMessage.userText(largeText)).toJsonAST.toOption.get,
+      58,
+    ).toJson
+
+    val program =
+      ZIO.scoped {
+        for
+          port <- freeLocalPort
+          config = A2AServerLive.Config(
+            name = "LargeBodyJvmTest",
+            description = "Large body JVM test server",
+            host = "127.0.0.1",
+            port = port,
+            executionOverride = Some(completedExecution),
+          )
+          _ <- A2AServerLive
+                 .create(config)
+                 .timeoutFail(new RuntimeException("server did not become ready"))(10.seconds)
+          result <- post(
+                      s"http://127.0.0.1:$port/",
+                      body,
+                      Map("Content-Type" -> A2AContentType.Json, A2AHeader.Version -> A2AProtocol.Version),
+                    )
+          response <- ZIO.fromEither(result._2.fromJson[JsonRpcResponse].left.map(new RuntimeException(_)))
+          task     <- sendTask(response)
+        yield (result._1, task)
+      }
+
+    runTask(program).map { case (status, task) =>
+      assertEquals(status, 200)
+      assertEquals(task.status.state, TaskState.Completed)
+    }
+
   test("JVM start fails when the configured port is already bound"):
     val program =
       ZIO.scoped {