diff --git a/docs/openapi.json b/docs/openapi.json
index ed9b0b96..ecd56e4d 100644
--- a/docs/openapi.json
+++ b/docs/openapi.json
@@ -819,6 +819,13 @@
             "example": "1.0",
             "nullable": true
           },
+          "guideline": {
+            "type": "string",
+            "description": "A guideline to be used in the chat_template",
+            "default": "null",
+            "example": "null",
+            "nullable": true
+          },
           "logit_bias": {
             "type": "array",
             "items": {
diff --git a/router/src/infer/chat_template.rs b/router/src/infer/chat_template.rs
index 24a00352..7c2753ed 100644
--- a/router/src/infer/chat_template.rs
+++ b/router/src/infer/chat_template.rs
@@ -48,6 +48,7 @@ impl ChatTemplate {
 
     pub(crate) fn apply(
         &self,
+        guideline: Option<&str>,
         mut messages: Vec<Message>,
         grammar_with_prompt: Option<(GrammarType, String)>,
     ) -> Result<String, InferError> {
@@ -65,6 +66,7 @@ impl ChatTemplate {
 
         self.template
             .render(ChatTemplateInputs {
+                guideline,
                 messages,
                 bos_token: self.bos_token.as_deref(),
                 eos_token: self.eos_token.as_deref(),
@@ -731,6 +733,19 @@ mod tests {
                 },
                 target: "You are a friendly chatbot who always responds in the style of a pirateYou are a friendly chatbot who always responds in the style of a pirate### Instruction: Hello, how are you?### Response: I'm doing great. How can I help you today?### Instruction: I'd like to show off how chat templating works!",
             },
+            ChatTemplateTestItem {
+                name: "google/shieldgemma-9b",
+                chat_template: "{{- bos_token }}\n{%- if messages[-1].role == 'user' %}\n    {{- \"You are a policy expert trying to help determine whether a user prompt is in violation of the defined safety policies.\\n\\n\" }}\n    {{- \"<start_of_turn>\\n\" }}\n    {{- \"Human Question: \" + messages[-1].content }}\n    {{- \"\\n<end_of_turn>\\n\\n\" }}\n    {{- \"Our safety principle is defined in the below:\\n\\n\" }}\n    {{- \"* \" + guideline + \"\\n\" }}\n    {{- \"\\n===\\n\\n\" }}\n    {{- \"Does the human question violate the above principle? Your answer must start with 'Yes' or 'No'. And then walk through step by step to be sure we answer correctly.\\n\\n\" }}\n{%- else %}\n    {{- \"You are a policy expert trying to help determine whether an AI response to a prompt is in violation of the defined safety policies.\\n\\n\" }}\n    {{- \"<start_of_turn>\\n\" }}\n    {{- \"Human Question: \" + messages[-2].content }}\n    {{- \"\\n<end_of_turn>\\n\" }}\n    {{- \"<start_of_turn>\\n\" }}\n    {{- \"Chatbot Response: \" + messages[-1].content }}\n    {{- \"\\n<end_of_turn>\\n\\n\" }}\n    {{- \"Our safety principle is defined in the below:\\n\\n\" }}\n    {{- \"* \" + guideline + \"\\n\" }}\n    {{- \"\\n===\\n\\n\" }}\n    {{- \"Does the Chatbot Response violate the above principle? Your answer must  start with 'Yes' or 'No'. And then walk through step by step to be sure we answer correctly.\\n\\n\" }}\n{%- endif %}\n\n",
+                input: ChatTemplateInputs {
+                    messages: example_chat_with_system.clone(),
+                    add_generation_prompt: false,
+                    bos_token: Some("<s>"),
+                    eos_token: Some("</s>"),
+                    guideline: Some("Do not use offensive language."),
+                    ..Default::default()
+                },
+                target: "<s>You are a policy expert trying to help determine whether a user prompt is in violation of the defined safety policies.\n\n<start_of_turn>\nHuman Question: I'd like to show off how chat templating works!\n<end_of_turn>\n\nOur safety principle is defined in the below:\n\n* Do not use offensive language.\n\n===\n\nDoes the human question violate the above principle? Your answer must start with 'Yes' or 'No'. And then walk through step by step to be sure we answer correctly.\n\n",
+            },
         ];
 
         #[allow(unused_variables)] // name is unused
diff --git a/router/src/infer/mod.rs b/router/src/infer/mod.rs
index 534a2647..58d5cf9a 100644
--- a/router/src/infer/mod.rs
+++ b/router/src/infer/mod.rs
@@ -138,13 +138,14 @@ impl Infer {
     #[instrument(skip_all)]
     pub(crate) fn apply_chat_template(
         &self,
+        guideline: Option<String>,
         messages: Vec<Message>,
         grammar_with_prompt: Option<(GrammarType, String)>,
     ) -> Result<String, InferError> {
         self.chat_template
             .as_ref()
             .ok_or_else(|| InferError::TemplateError(ErrorKind::TemplateNotFound.into()))?
-            .apply(messages, grammar_with_prompt)
+            .apply(guideline.as_deref(), messages, grammar_with_prompt)
             .map_err(|e| {
                 metrics::counter!("tgi_request_failure", "err" => "template").increment(1);
                 tracing::error!("{e}");
diff --git a/router/src/lib.rs b/router/src/lib.rs
index 66738706..0a15c495 100644
--- a/router/src/lib.rs
+++ b/router/src/lib.rs
@@ -858,6 +858,11 @@ pub(crate) struct ChatRequest {
     #[serde(default)]
     #[schema(nullable = true, default = "null", example = "null")]
     pub response_format: Option<GrammarType>,
+
+    /// A guideline to be used in the chat_template
+    #[serde(default)]
+    #[schema(nullable = true, default = "null", example = "null")]
+    pub guideline: Option<String>,
 }
 
 fn default_tool_prompt() -> Option<String> {
@@ -965,6 +970,7 @@ pub(crate) struct ChatTemplateInputs<'a> {
     add_generation_prompt: bool,
     tools: Option<&'a str>,
     tools_prompt: Option<&'a str>,
+    guideline: Option<&'a str>,
 }
 
 #[derive(Clone, Deserialize, Serialize, ToSchema, Default, Debug, PartialEq)]
diff --git a/router/src/server.rs b/router/src/server.rs
index 1d1cd36a..8c0bd762 100644
--- a/router/src/server.rs
+++ b/router/src/server.rs
@@ -141,6 +141,7 @@ async fn get_chat_tokenize(
         tool_prompt,
         temperature,
         response_format,
+        guideline,
         ..
     } = req;
 
@@ -151,6 +152,7 @@ async fn get_chat_tokenize(
         tools,
         tool_choice,
         &tool_prompt,
+        guideline,
         messages,
     )?;
 
@@ -1123,6 +1125,7 @@ async fn chat_completions(
         tool_prompt,
         temperature,
         response_format,
+        guideline,
         ..
     } = req;
 
@@ -1142,6 +1145,7 @@ async fn chat_completions(
         tools,
         tool_choice,
         &tool_prompt,
+        guideline,
         messages,
     )?;
 
@@ -2402,6 +2406,7 @@ fn prepare_chat_input(
     tools: Option<Vec<Tool>>,
     tool_choice: ToolChoice,
     tool_prompt: &str,
+    guideline: Option<String>,
     messages: Vec<Message>,
 ) -> Result<PreparedInput, InferError> {
     if response_format.is_some() && tools.is_some() {
@@ -2411,7 +2416,7 @@ fn prepare_chat_input(
     }
 
     if let Some(format) = response_format {
-        let inputs = infer.apply_chat_template(messages, None)?;
+        let inputs = infer.apply_chat_template(guideline, messages, None)?;
         return Ok((inputs, Some(format), None));
     }
 
@@ -2423,6 +2428,6 @@ fn prepare_chat_input(
     let tools_grammar_prompt = tool_grammar
         .as_ref()
         .map(|t| (GrammarType::Json(serde_json::json!(t)), tool_prompt.into()));
-    let inputs = infer.apply_chat_template(messages, tools_grammar_prompt)?;
+    let inputs = infer.apply_chat_template(guideline, messages, tools_grammar_prompt)?;
     Ok((inputs, grammar, tool_grammar))
 }