diff --git a/buildDeps.sc b/buildDeps.sc
index 230b05a..8dbd8b3 100644
--- a/buildDeps.sc
+++ b/buildDeps.sc
@@ -3,7 +3,7 @@ import mill.define._
 import mill.scalalib._
 
 object alloy {
-  val alloyVersion = "0.3.4"
+  val alloyVersion = "0.3.9"
   val core =
     ivy"com.disneystreaming.alloy:alloy-core:$alloyVersion"
   val protobuf =
@@ -25,7 +25,7 @@ object swagger {
   )
 }
 object smithy {
-  val smithyVersion = "1.41.1"
+  val smithyVersion = "1.49.0"
   val model = ivy"software.amazon.smithy:smithy-model:$smithyVersion"
   val build = ivy"software.amazon.smithy:smithy-build:$smithyVersion"
   val diff = ivy"software.amazon.smithy:smithy-diff:$smithyVersion"
diff --git a/modules/openapi/tests/resources/issue-23.json b/modules/openapi/tests/resources/issue-23.json
index d35b11b..09b88ef 100644
--- a/modules/openapi/tests/resources/issue-23.json
+++ b/modules/openapi/tests/resources/issue-23.json
@@ -15,7 +15,7 @@
     }
   ],
   "paths": {
-    "/Testers/{id}": {
+    "/Testers/{id_}": {
       "get": {
         "tags": ["Testers"],
         "summary": "Testers_GetTest",
diff --git a/modules/proto/src/smithytranslate/proto3/internals/Compiler.scala b/modules/proto/src/smithytranslate/proto3/internals/Compiler.scala
index 2227f00..e46a1a4 100644
--- a/modules/proto/src/smithytranslate/proto3/internals/Compiler.scala
+++ b/modules/proto/src/smithytranslate/proto3/internals/Compiler.scala
@@ -452,9 +452,16 @@ private[proto3] class Compiler(model: Model, allShapes: Boolean) {
             val isMap = targetShape.isMapShape()
             memberHasWrapped || targetHasWrapped || isList || isMap
           }
+          val maybeTimestampFormat = extractTimestampFormat(m)
           val fieldType =
             targetShape
-              .accept(typeVisitor(isWrapped = isWrapped, numType))
+              .accept(
+                typeVisitor(
+                  isWrapped = isWrapped,
+                  numType,
+                  maybeTimestampFormat
+                )
+              )
               .get
           val isDeprecated = m.hasTrait(classOf[DeprecatedTrait])
           Field(
diff --git a/modules/proto/tests/src/smithytranslate/proto3/internals/CompilerRendererSuite.scala b/modules/proto/tests/src/smithytranslate/proto3/internals/CompilerRendererSuite.scala
index 76577a4..ce2695f 100644
--- a/modules/proto/tests/src/smithytranslate/proto3/internals/CompilerRendererSuite.scala
+++ b/modules/proto/tests/src/smithytranslate/proto3/internals/CompilerRendererSuite.scala
@@ -67,6 +67,36 @@ class CompilerRendererSuite extends FunSuite {
     convertCheck(source, Map("com/example/example.proto" -> expected))
   }
 
+  test("top level - union with timestamp formats") {
+    val source = """|namespace com.example
+                    |
+                    |use alloy.proto#protoTimestampFormat
+                    |
+                    |union MyUnion {
+                    |  one: Timestamp
+                    |  @protoTimestampFormat("EPOCH_MILLIS")
+                    |  two: Timestamp
+                    |}
+                    |""".stripMargin
+
+    val expected = """|syntax = "proto3";
+                      |
+                      |package com.example;
+                      |
+                      |import "google/protobuf/timestamp.proto";
+                      |
+                      |import "alloy/protobuf/types.proto";
+                      |
+                      |message MyUnion {
+                      |  oneof definition {
+                      |    google.protobuf.Timestamp one = 1;
+                      |    alloy.protobuf.EpochMillisTimestamp two = 2;
+                      |  }
+                      |}
+                      |""".stripMargin
+    convertCheck(source, Map("com/example/example.proto" -> expected))
+  }
+
   test("@protoInlinedOneOf union - used within only one data structure") {
     val source = """|namespace com.example
                     |