add function to deserialize json arguments into string

async-openai/src/types/chat.rs

@@ -81,9 +81,19 @@ pub struct FunctionCall {
     /// The name of the function to call.
     pub name: String,
     /// The arguments to call the function with, as generated by the model in JSON format. Note that the model does not always generate valid JSON, and may hallucinate parameters not defined by your function schema. Validate the arguments in your code before calling your function.
+    #[serde(deserialize_with = "deserialize_arguments_as_string")]
     pub arguments: String,
 }
 
+fn deserialize_arguments_as_string<'de, D>(deserializer: D) -> Result<String, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let value = serde_json::Value::deserialize(deserializer)?;
+    Ok(value.to_string())
+}
+
+
 /// Usage statistics for the completion request.
 #[derive(Debug, Deserialize, Serialize, Clone, PartialEq)]
 pub struct CompletionUsage {

async-openai/src/types/step.rs

@@ -197,11 +197,20 @@ pub struct RunStepFunctionObject {
     /// The name of the function.
     pub name: String,
     /// The arguments passed to the function.
+    #[serde(deserialize_with = "deserialize_arguments_as_string")]
     pub arguments: String,
     /// The output of the function. This will be `null` if the outputs have not been [submitted](https://platform.openai.com/docs/api-reference/runs/submitToolOutputs) yet.
     pub output: Option<String>,
 }
 
+fn deserialize_arguments_as_string<'de, D>(deserializer: D) -> Result<String, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let value = serde_json::Value::deserialize(deserializer)?;
+    Ok(value.to_string())
+}
+
 #[derive(Clone, Serialize, Debug, Deserialize, PartialEq)]
 pub struct RunStepFunctionObjectDelta {
     /// The name of the function.