diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index fbf9ea1..ba0f13f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -1,6 +1,8 @@
 name: Test
 
-on: push
+on:
+  pull_request:
+  push:
 
 jobs:
   test:
diff --git a/src/v1/chat.rs b/src/v1/chat.rs
index 455303e..2ce252a 100644
--- a/src/v1/chat.rs
+++ b/src/v1/chat.rs
@@ -30,12 +30,17 @@ impl ChatMessage {
     }
 }
 
+/// See the [Mistral AI API documentation](https://docs.mistral.ai/capabilities/completion/#chat-messages) for more information.
 #[derive(Clone, Debug, Eq, PartialEq, Deserialize, Serialize)]
 pub enum ChatMessageRole {
+    #[serde(rename = "system")]
+    System,
     #[serde(rename = "assistant")]
     Assistant,
     #[serde(rename = "user")]
     User,
+    #[serde(rename = "tool")]
+    Tool,
 }
 
 /// The format that the model must output.