diff --git a/router/src/infer/chat_template.rs b/router/src/infer/chat_template.rs
index 6a9289c0..12a79f6a 100644
--- a/router/src/infer/chat_template.rs
+++ b/router/src/infer/chat_template.rs
@@ -1,5 +1,5 @@
 use crate::infer::InferError;
-use crate::{ChatTemplateInputs, Message, MessageChunk, TextMessage, TokenizerConfigToken, Tool};
+use crate::{ChatTemplateInputs, Message, MessageChunk, MessageContent, TextMessage, TokenizerConfigToken, Tool};
 use chrono::Local;
 use minijinja::{Environment, ErrorKind, Template};
 use minijinja_contrib::pycompat;
@@ -74,14 +74,38 @@ impl ChatTemplate {
                     format!("\n---\n{}", tool_prompt)
                 };
                 if let Some(last_message) = messages.last_mut() {
-                    last_message.content.push(MessageChunk::Text { text });
+                    if let Some(ref mut content) = last_message.content {
+                        content.push(MessageChunk::Text { text });
+                    } else {
+                        last_message.content = Some(MessageContent::SingleText(text));
+                    }
                 }
                 Some(tools)
             }
             None => None,
         };
 
-        let messages: Vec<TextMessage> = messages.into_iter().map(|c| c.into()).collect();
+        let messages: Vec<TextMessage> = messages
+            .into_iter()
+            .map(|m| {
+                if m.role == "assistant" && m.tool_calls.is_some() && m.content.is_none() {
+                    // For assistant messages with tool calls but no content,
+                    // just use the standard conversion which will handle None content
+                    Ok(m.into())
+                } else if m.content.is_none() {
+                    // For messages requiring content but having none, return error
+                    return Err(InferError::TemplateError(
+                        minijinja::Error::new(
+                            minijinja::ErrorKind::SyntaxError,
+                            "Content is required for this message type",
+                        )
+                    ));
+                } else {
+                    Ok(m.into())
+                }
+            })
+            .collect::<Result<_, _>>()?;
+
         let final_message = messages.last().cloned();
         let mut rendered_template = self
             .template
diff --git a/router/src/lib.rs b/router/src/lib.rs
index 959da7f4..e9d4bb59 100644
--- a/router/src/lib.rs
+++ b/router/src/lib.rs
@@ -1189,10 +1189,13 @@ pub struct Message {
     #[schema(example = "user")]
     role: String,
     #[schema(example = "My name is David and I")]
-    pub content: MessageContent,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    content: Option<MessageContent>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[schema(example = "\"David\"")]
     name: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    tool_calls: Option<Vec<ToolCall>>,
 }
 
 #[derive(Clone, Deserialize, Serialize, ToSchema, Debug, PartialEq)]
@@ -1232,8 +1235,8 @@ impl From<Message> for TextMessage {
         TextMessage {
             role: value.role,
             content: match value.content {
-                MessageContent::SingleText(text) => text,
-                MessageContent::MultipleChunks(chunks) => chunks
+                Some(MessageContent::SingleText(text)) => text,
+                Some(MessageContent::MultipleChunks(chunks)) => chunks
                     .into_iter()
                     .map(|chunk| match chunk {
                         MessageChunk::Text { text } => text,
@@ -1241,6 +1244,7 @@ impl From<Message> for TextMessage {
                     })
                     .collect::<Vec<_>>()
                     .join(""),
+                None => String::new(),
             },
         }
     }