diff --git a/src/v1/message.rs b/src/v1/message.rs
index e82644b..094689c 100644
--- a/src/v1/message.rs
+++ b/src/v1/message.rs
@@ -101,7 +101,7 @@ pub struct Content {
 #[derive(Debug, Deserialize, Serialize)]
 pub struct ContentText {
     pub value: String,
-    pub annotations: Vec<String>,
+    pub annotations: Vec<ContentTextAnnotations>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -132,3 +132,38 @@ pub struct ListMessageFile {
     pub has_more: bool,
     pub headers: Option<HashMap<String, String>>,
 }
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(tag = "type")]
+#[serde(rename_all = "snake_case")]
+pub enum ContentTextAnnotations {
+    FileCitation(ContentTextAnnotationsFileCitationObject),
+    FilePath(ContentTextAnnotationsFilePathObject),
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct ContentTextAnnotationsFileCitationObject {
+    pub text: String,
+    pub file_citation: FileCitation,
+    pub start_index: u32,
+    pub end_index: u32,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct FileCitation {
+    pub file_id: String,
+    pub quote: Option<String>,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct ContentTextAnnotationsFilePathObject {
+    pub text: String,
+    pub file_path: FilePath,
+    pub start_index: u32,
+    pub end_index: u32,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct FilePath {
+    pub file_id: String,
+}