feat: improve tool serialization

router/src/lib.rs

@@ -591,44 +591,39 @@ mod deserialize_tool_choice {
     }
 }
 
-#[derive(Clone, Debug, Deserialize, Serialize, ToSchema, Default)]
+#[derive(Debug, Deserialize, Serialize, ToSchema)]
 pub struct Tools {
-    // rename to "$function" to avoid conflicts with other fields
-    #[serde(rename = "$function")]
-    pub function: std::collections::HashMap<String, serde_json::Value>,
-    pub any_of: Vec<FunctionRef>,
+    #[serde(flatten)]
+    functions_map: FunctionsMap,
+    properties: Properties,
 }
 
-// Allows Tools to be converted to a valid JSON schema object
-impl From<Tools> for serde_json::Value {
-    fn from(tools: Tools) -> Self {
-        let mut map = serde_json::Map::new();
-        let mut functions = serde_json::Map::new();
-        for (name, value) in tools.function {
-            functions.insert(name, value);
-        }
-        map.insert("$functions".to_string(), serde_json::json!(functions));
-        let mut properties = serde_json::Map::new();
-        let mut function = serde_json::Map::new();
-        function.insert("anyOf".to_string(), serde_json::json!(tools.any_of));
-        properties.insert("function".to_string(), serde_json::json!(function));
-        map.insert("properties".to_string(), serde_json::json!(properties));
-        serde_json::Value::Object(map)
-    }
+#[derive(Debug, Serialize, Deserialize)]
+struct FunctionsMap {
+    #[serde(rename = "$functions")]
+    functions: std::collections::HashMap<String, serde_json::Value>,
 }
 
-#[derive(Clone, Debug, Deserialize, Serialize, ToSchema)]
-pub struct FunctionRef {
+#[derive(Debug, Serialize, Deserialize)]
+struct FunctionRef {
     #[serde(rename = "$ref")]
-    pub _ref: String,
+    ref_path: String,
 }
 
-impl FunctionRef {
-    pub fn new(name: &str) -> Self {
-        Self {
-            _ref: format!("#/$functions/{}", name),
-        }
-    }
+#[derive(Debug, Serialize, Deserialize)]
+struct Properties {
+    #[serde(serialize_with = "serialize_function")]
+    function: Vec<FunctionRef>,
+}
+
+fn serialize_function<S>(functions: &Vec<FunctionRef>, serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    use serde::ser::SerializeStruct;
+    let mut state = serializer.serialize_struct("Function", 1)?;
+    state.serialize_field("anyOf", functions)?;
+    state.end()
 }
 
 #[derive(Clone, Debug, Deserialize, Serialize, ToSchema)]

router/src/server.rs

@@ -10,7 +10,7 @@ use crate::{
     HubTokenizerConfig, Infer, Info, Message, PrefillToken, SimpleToken, StreamDetails,
     StreamResponse, Token, TokenizeResponse, Usage, Validation, VertexRequest, VertexResponse,
 };
-use crate::{Function, FunctionRef, ToolCall, ToolType, Tools};
+use crate::{Function, FunctionRef, FunctionsMap, Properties, ToolCall, ToolType, Tools};
 use axum::extract::Extension;
 use axum::http::{HeaderMap, Method, StatusCode};
 use axum::response::sse::{Event, KeepAlive, Sse};
@@ -629,11 +629,15 @@ async fn chat_completions(
             .collect();
 
         let tools = Tools {
-            function: functions,
-            any_of: tools_to_use
-                .iter()
-                .map(|tool| FunctionRef::new(&tool.function.name))
-                .collect(),
+            functions_map: FunctionsMap { functions },
+            properties: Properties {
+                function: tools_to_use
+                    .iter()
+                    .map(|tool| FunctionRef {
+                        ref_path: format!("#/$functions/{}", tool.function.name.clone()),
+                    })
+                    .collect(),
+            },
         };
 
         let tools_str = serde_json::to_string(&tools).map_err(|e| {
@@ -646,7 +650,7 @@ async fn chat_completions(
             )
         })?;
         inputs = format!("{inputs}{tool_prompt}{tools_str}");
-        Some(GrammarType::Json(tools.into()))
+        Some(GrammarType::Json(serde_json::json!(tools)))
     } else {
         None
     };