diff --git a/README.md b/README.md
index efe2bfa..f599e7c 100644
--- a/README.md
+++ b/README.md
@@ -16,18 +16,17 @@ $ cargo add openai-api
 # Quickstart
 
 ```rust
-use openai_api::OpenAIClient;
-
 #[tokio::main]
-async fn main() {
-    let api_token = std::env::var("OPENAI_SK").unwrap();
-    let client = OpenAIClient::new(&api_token);
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let api_token = std::env::var("OPENAI_SK")?;
+    let client = openai_api::Client::new(&api_token);
     let prompt = String::from("Once upon a time,");
     println!(
         "{}{}",
         prompt,
-        client.complete(prompt.as_str()).await.unwrap()
+        client.complete(prompt.as_str()).await?
     );
+    Ok(())
 }
 ```
 # Basic Usage
@@ -37,7 +36,7 @@ async fn main() {
 For simple demos and debugging, you can do a completion and use the `Display` instance of a `Completion` object to convert it to a string:
 
 ```rust
-let response = client.complete("Once upon a time").await?;
+let response = client.complete_prompt("Once upon a time").await?;
 println!("{}", response);
 ```
 
@@ -51,7 +50,7 @@ let args = openai_api::api::CompletionArgs::builder()
         .temperature(0.7)
         .top_p(0.9)
         .stop(vec!["\n".into()]);
-let response = args.complete(&client).await?;
+let completion = client.complete_prompt(args).await?;
 println!("Response: {}", response.choices[0].text);
 println!("Model used: {}", response.model);
 ```
diff --git a/examples/chatloop.rs b/examples/chatloop.rs
index 94a7752..26cec0a 100644
--- a/examples/chatloop.rs
+++ b/examples/chatloop.rs
@@ -9,8 +9,8 @@ The assistant is helpful, creative, clever, and very friendly.
 Human: Hello, who are you?
 AI: I am an AI. How can I help you today?";
 #[tokio::main]
-async fn main() {
-    let api_token = std::env::var("OPENAI_SK").unwrap();
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let api_token = std::env::var("OPENAI_SK")?;
     let client = Client::new(&api_token);
     let mut context = String::from(START_PROMPT);
     let mut args = CompletionArgs::builder();
@@ -28,7 +28,7 @@ async fn main() {
             break;
         }
         context.push_str("\nAI:");
-        match args.prompt(context.as_str()).complete(&client).await {
+        match args.prompt(context.as_str()).complete_prompt(&client).await {
             Ok(completion) => {
                 println!("\x1b[1;36m{}\x1b[1;0m", completion);
                 context.push_str(&completion.choices[0].text);
@@ -40,4 +40,5 @@ async fn main() {
         }
     }
     println!("Full conversation:\n{}", context);
+    Ok(())
 }
diff --git a/src/lib.rs b/src/lib.rs
index b4d16bb..4840b64 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -21,7 +21,7 @@ pub mod api {
     }
 
     /// Engine description type
-    #[derive(Deserialize, Debug, Eq, PartialEq)]
+    #[derive(Deserialize, Debug, Eq, PartialEq, Clone)]
     pub struct EngineInfo {
         pub id: Engine,
         pub owner: String,
@@ -145,7 +145,7 @@ pub mod api {
     }
 
     /// Represents a non-streamed completion response
-    #[derive(Deserialize, Debug)]
+    #[derive(Deserialize, Debug, Clone)]
     pub struct Completion {
         /// Completion unique identifier
         pub id: String,
@@ -164,7 +164,7 @@ pub mod api {
     }
 
     /// A single completion result
-    #[derive(Deserialize, Debug)]
+    #[derive(Deserialize, Debug, Clone)]
     pub struct Choice {
         /// The text of the completion. Will contain the prompt if echo is True.
         pub text: String,
@@ -183,7 +183,7 @@ pub mod api {
     }
 
     /// Represents a logprobs subdocument
-    #[derive(Deserialize, Debug)]
+    #[derive(Deserialize, Debug, Clone)]
     pub struct LogProbs {
         pub tokens: Vec<String>,
         pub token_logprobs: Vec<Option<f64>>,
@@ -192,11 +192,11 @@ pub mod api {
     }
 
     /// Reason a prompt completion finished.
-    #[derive(Deserialize, Debug, Eq, PartialEq)]
+    #[derive(Deserialize, Debug, Eq, PartialEq, Clone, Copy)]
     #[non_exhaustive]
     pub enum FinishReason {
         /// The maximum length was reached
-        #[serde(rename = "max_tokens")]
+        #[serde(rename = "length")]
         MaxTokensReached,
         /// The stop token was encountered
         #[serde(rename = "stop")]
@@ -204,7 +204,7 @@ pub mod api {
     }
 
     /// Error response object from the server
-    #[derive(Deserialize, Debug, Eq, PartialEq)]
+    #[derive(Deserialize, Debug, Eq, PartialEq, Clone)]
     pub struct ErrorMessage {
         pub message: String,
         #[serde(rename = "type")]
@@ -325,6 +325,7 @@ fn sync_client(token: &str) -> ureq::Agent {
 }
 
 /// Client object. Must be constructed to talk to the API.
+#[derive(Debug, Clone)]
 pub struct Client {
     #[cfg(feature = "async")]
     async_client: surf::Client,
@@ -732,7 +733,7 @@ mod unit {
                     "text": " there was a girl who",
                     "index": 0,
                     "logprobs": null,
-                    "finish_reason": "max_tokens"
+                    "finish_reason": "length"
                     }
                 ]
                 }"#,