diff --git a/dev/restate/service/protocol.proto b/dev/restate/service/protocol.proto
index 8131bfb..9c4fbce 100644
--- a/dev/restate/service/protocol.proto
+++ b/dev/restate/service/protocol.proto
@@ -40,10 +40,8 @@ message StartMessage {
   repeated StateEntry state_map = 4;
   bool partial_state = 5;
 
-  repeated Header headers = 6;
-
   // If this invocation has a key associated (e.g. for objects and workflows), then this key is filled in. Empty otherwise.
-  string key = 7;
+  string key = 6;
 }
 
 // Type: 0x0000 + 1
@@ -106,20 +104,19 @@ message EndMessage {
 
 // ------ Input and output ------
 
-// Completable: Yes
+// Completable: No
 // Fallible: No
 // Type: 0x0400 + 0
-message PollInputStreamEntryMessage {
-  oneof result {
-    bytes value = 14;
-    Failure failure = 15;
-  }
+message InputEntryMessage {
+  repeated Header headers = 1;
+
+  bytes value = 14;
 }
 
 // Completable: No
 // Fallible: No
 // Type: 0x0400 + 1
-message OutputStreamEntryMessage {
+message OutputEntryMessage {
   oneof result {
     bytes value = 14;
     Failure failure = 15;
diff --git a/service-invocation-protocol.md b/service-invocation-protocol.md
index d592ad0..7aef70e 100644
--- a/service-invocation-protocol.md
+++ b/service-invocation-protocol.md
@@ -282,7 +282,7 @@ descriptions in [`protocol.proto`](dev/restate/service/protocol.proto).
 
 | Message                         | Type     | Completable | Fallible | Description                                                                                                                                                      |
 | ------------------------------- | -------- | ----------- | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `PollInputStreamEntryMessage`   | `0x0400` | Yes         | No       | Carries the invocation input message(s) of the invocation. Note: currently the runtime always sends this entry completed, but this may change in future.         |
+| `InputEntryMessage`             | `0x0400` | No          | No       | Carries the invocation input message(s) of the invocation.                                                                                                       |
 | `GetStateEntryMessage`          | `0x0800` | Yes         | No       | Get the value of a service instance state key.                                                                                                                   |
 | `GetStateKeysEntryMessage`      | `0x0804` | Yes         | No       | Get all the known state keys for this service instance. Note: the completion value for this message is a protobuf of type `GetStateKeysEntryMessage.StateKeys`.  |
 | `SleepEntryMessage`             | `0x0C00` | Yes         | No       | Initiate a timer that completes after the given time.                                                                                                            |
@@ -290,7 +290,7 @@ descriptions in [`protocol.proto`](dev/restate/service/protocol.proto).
 | `AwakeableEntryMessage`         | `0x0C03` | Yes         | No       | Arbitrary result container which can be completed from another service, given a specific id. See [Awakeable identifier](#awakeable-identifier) for more details. |
 | `BackgroundInvokeEntryMessage`  | `0x0C02` | No          | Yes      | Invoke another Restate service at the given time, without waiting for the response.                                                                              |
 | `CompleteAwakeableEntryMessage` | `0x0C04` | No          | Yes      | Complete an `Awakeable`, given its id. See [Awakeable identifier](#awakeable-identifier) for more details.                                                       |
-| `OutputStreamEntryMessage`      | `0x0401` | No          | No       | Carries the invocation output message(s) or terminal failure of the invocation.                                                                                  |
+| `OutputEntryMessage`            | `0x0401` | No          | No       | Carries the invocation output message(s) or terminal failure of the invocation.                                                                                  |
 | `SetStateEntryMessage`          | `0x0800` | No          | No       | Set the value of a service instance state key.                                                                                                                   |
 | `ClearStateEntryMessage`        | `0x0801` | No          | No       | Clear the value of a service instance state key.                                                                                                                 |
 | `ClearAllStateEntryMessage`     | `0x0802` | No          | No       | Clear all the values of the service instance state.                                                                                                              |