add OpenAI like tool_choice for named choice

docs/openapi.json

@@ -2137,6 +2137,24 @@
                 "$ref": "#/components/schemas/FunctionName"
               }
             }
+          },
+          {
+            "type": "object",
+            "required": [
+              "type",
+              "function"
+            ],
+            "properties": {
+              "type": {
+                "type": "string",
+                "enum": [
+                  "function"
+                ]
+              },
+              "function": {
+                "$ref": "#/components/schemas/FunctionName"
+              }
+            }
           }
         ],
         "description": "Controls which (if any) tool is called by the model.",

router/src/lib.rs

@@ -968,9 +968,18 @@ pub enum ToolType {
     NoTool,
     /// Forces the model to call a specific tool.
     #[schema(rename = "function")]
+    #[serde(alias = "function")]
     Function(FunctionName),
 }
 
+
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+#[serde(tag = "type")]
+pub enum TypedChoice {
+    #[serde(rename = "function")]
+    Function{function: FunctionName},
+}
+
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ToSchema)]
 pub struct FunctionName {
     pub name: String,
@@ -986,8 +995,10 @@ enum ToolTypeDeserializer {
     Null,
     String(String),
     ToolType(ToolType),
+    TypedChoice(TypedChoice) //this is the OpenAI schema
 }
 
+
 impl From<ToolTypeDeserializer> for ToolChoice {
     fn from(value: ToolTypeDeserializer) -> Self {
         match value {
@@ -997,6 +1008,7 @@ impl From<ToolTypeDeserializer> for ToolChoice {
                 "auto" => ToolChoice(Some(ToolType::OneOf)),
                 _ => ToolChoice(Some(ToolType::Function(FunctionName { name: s }))),
             },
+            ToolTypeDeserializer::TypedChoice(TypedChoice::Function{function}) => ToolChoice(Some(ToolType::Function(function))),
             ToolTypeDeserializer::ToolType(tool_type) => ToolChoice(Some(tool_type)),
         }
     }