diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1bd2eb7..ba623b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 - Update OpenAI Embeddings model to support all allowed types of input [#6](https://github.com/hypermodeAI/models-as/pull/6)
 - More updates for OpenAI Embeddings model [#7](https://github.com/hypermodeAI/models-as/pull/7)
+- Add documentation comments for OpenAI Chat model [#8](https://github.com/hypermodeAI/models-as/pull/8)
 
 ## 2024-06-28 - Version 0.1.6
 
diff --git a/src/models/openai/chat.ts b/src/models/openai/chat.ts
index 08c2c20..d0c30bb 100644
--- a/src/models/openai/chat.ts
+++ b/src/models/openai/chat.ts
@@ -1,63 +1,144 @@
 import { Model } from "../..";
 
-// Reference: https://platform.openai.com/docs/api-reference/chat
-
+/**
+ * Provides input and output types that conform to the OpenAI Chat API.
+ *
+ * Reference: https://platform.openai.com/docs/api-reference/chat
+ */
 export class ChatModel extends Model<ChatInput, ChatOutput> {
+  /**
+   * Creates an input object for the OpenAI Chat API.
+   *
+   * @param messages: An array of messages to send to the chat model.
+   * @returns An input object that can be passed to the `invoke` method.
+   */
   createInput(messages: Message[]): ChatInput {
     const model = this.info.fullName;
     return <ChatInput>{ model, messages };
   }
 }
 
-
+/**
+ * The input object for the OpenAI Chat API.
+ */
 @json
 class ChatInput {
+  /**
+   * The name of the model to use for the chat.
+   * Must be the exact string expected by the model provider.
+   * For example, "gpt-3.5-turbo".
+   *
+   * @remarks
+   * This field is automatically set by the `createInput` method when creating this object.
+   * It does not need to be set manually.
+   */
   model!: string;
-  messages!: Message[];
 
+  /**
+   * An array of messages to send to the chat model.
+   */
+  messages!: Message[];
 
+  /**
+   * Number between `-2.0` and `2.0`.
+   *
+   * Positive values penalize new tokens based on their existing frequency in the text so far,
+   * decreasing the model's likelihood to repeat the same line verbatim.
+   *
+   * @default 0.0
+   */
   @alias("frequency_penalty")
   @omitif("this.frequencyPenalty == 0.0")
   frequencyPenalty: f64 = 0.0;
 
-
+  /**
+   * Modifies the likelihood of specified tokens appearing in the completion.
+   *
+   * Accepts an object that maps tokens (specified by their token ID in the tokenizer) to an associated bias value from -100 to 100.
+   * Mathematically, the bias is added to the logits generated by the model prior to sampling. The exact effect will vary per model,
+   * but values between -1 and 1 should decrease or increase likelihood of selection; values like -100 or 100 should result in a ban
+   * or exclusive selection of the relevant token.
+   */
   @alias("logit_bias")
   @omitnull()
   logitBias: Map<string, f64> | null = null;
 
-
+  /**
+   * Whether to return log probabilities of the output tokens or not,
+   *
+   * If true, returns the log probabilities of each output token returned in the content of message.
+   *
+   * @default false
+   */
   @omitif("this.logprobs == false")
   logprobs: bool = false;
 
-
+  /**
+   * An integer between 0 and 20 specifying the number of most likely tokens to return at each token position,
+   * each with an associated log probability. `logprobs` must be set to `true` if this parameter is used.
+   */
   @alias("top_logprobs")
   @omitif("this.logprobs == false")
   topLogprobs: i32 = 0;
 
-
+  /**
+   * The maximum number of tokens to generate in the chat completion.
+   *
+   * @default 4096
+   */
   @alias("max_tokens")
   @omitif("this.maxTokens == 4096")
   maxTokens: i32 = 4096; // TODO: make this an `i32 | null` when supported
 
-
+  /**
+   * The number of completions to generate for each prompt.
+   */
   @omitif("this.n == 1")
   n: i32 = 1;
 
-
+  /**
+   *
+   * Number between `-2.0` and `2.0`.
+   *
+   * Positive values penalize new tokens based on whether they appear in the text so far,
+   * increasing the model's likelihood to talk about new topics.
+   *
+   * @default 0.0
+   */
   @alias("presence_penalty")
   @omitif("this.presencePenalty == 0.0")
   presencePenalty: f64 = 0.0;
 
-
+  /**
+   * Specifies the format for the response.
+   *
+   * If set to `ResponseFormat.Json`, the response will be a JSON object.
+   *
+   * @default ResponseFormat.Text
+   */
   @alias("response_format")
   @omitif("this.responseFormat.type == 'text'")
   responseFormat: ResponseFormat = ResponseFormat.Text;
 
-
+  /**
+   * If specified, the model will make a best effort to sample deterministically, such that
+   * repeated requests with the same seed and parameters should return the same result.
+   * Determinism is not guaranteed, and you should use the `systemFingerprint` response
+   * parameter to monitor changes in the backend.
+   */
   @omitif("this.seed == -1")
   seed: i32 = -1; // TODO: make this an `i32 | null` when supported
 
+  /**
+   * Specifies the latency tier to use for processing the request.
+   */
+  @alias("service_tier")
+  @omitnull()
+  serviceTier: ServiceTier | null = null;
 
+  /**
+   * Up to 4 sequences where the API will stop generating further tokens.
+   */
   @omitnull()
   stop: string[] | null = null;
 
@@ -67,55 +148,170 @@ class ChatInput {
   // @alias("stream_options")
   // streamOptions: StreamOptions | null = null;
 
+  /**
+   * A number between `0.0` and `2.0` that controls the sampling temperature.
+   *
+   * Higher values like `0.8` will make the output more random, while lower values like `0.2` will make
+   * it more focused and deterministic.
+   *
+   * We generally recommend altering this or `topP` but not both.
+   *
+   * @default 1.0
+   */
   @omitif("this.temperature == 1.0")
   temperature: f64 = 1.0;
 
-
+  /**
+   * An alternative to sampling with temperature, called nucleus sampling, where the model
+   * considers the results of the tokens with `topP` probability mass.
+   *
+   * For example, `0.1` means only the tokens comprising the top 10% probability mass are considered.
+   *
+   * We generally recommend altering this or `temperature` but not both.
+   */
   @alias("top_p")
   @omitif("this.topP == 1.0")
   topP: f64 = 1.0;
 
-
+  /**
+   * A list of tools the model may call. Currently, only functions are supported as a tool.
+   * Use this to provide a list of functions the model may generate JSON inputs for.
+   * A max of 128 functions are supported.
+   */
   @omitnull()
   tools: Tool[] | null = null;
 
-
+  /**
+   * Controls which (if any) tool is called by the model.
+   * - `"none"` means the model will not call any tool and instead generates a message.
+   * - `"auto"` means the model can pick between generating a message or calling one or more tools.
+   * - `"required"` means the model must call one or more tools.
+   * - Specifying a particular tool via `{"type": "function", "function": {"name": "my_function"}}` forces the model to call that tool.
+   *
+   * `none` is the default when no tools are present. `auto` is the default if tools are present.
+   */
   @alias("tool_choice")
   @omitnull()
-  toolChoice: string | null = null; // TODO: verify this works
-
+  toolChoice: string | null = null; // TODO: Make this work with a custom tool object
 
+  /**
+   * Whether to enable parallel function calling during tool use.
+   *
+   * @default true
+   */
   @alias("parallel_tool_calls")
   @omitif("this.parallelToolCalls == true || !this.tools || this.tools!.length == 0")
   parallelToolCalls: bool = true;
 
-
+  /**
+   * The user ID to associate with the request.
+   * If not specified, the request will be anonymous.
+   * See https://platform.openai.com/docs/guides/safety-best-practices/end-user-ids
+   */
   @omitnull()
   user: string | null = null;
 }
 
+/**
+ * The OpenAI service tier used to process the request.
+ */
+// eslint-disable-next-line @typescript-eslint/no-namespace
+export namespace ServiceTier {
+  /**
+   * The OpenAI system will utilize scale tier credits until they are exhausted.
+   */
+  export const Auto = "auto";
+
+  /**
+   * The request will be processed using the default OpenAI service tier with a lower
+   * uptime SLA and no latency guarantee.
+   */
+  export const Default = "default";
+}
+export type ServiceTier = string;
 
+/**
+ * The output object for the OpenAI Chat API.
+ */
 @json
 class ChatOutput {
+  /**
+   * A unique identifier for the chat completion.
+   */
   id!: string;
+
+  /**
+   * The name of the output object type returned by the API.
+   * Always `"chat.completion"`.
+   */
   object!: string;
+
+  /**
+   * A list of chat completion choices. Can be more than one if `n` is greater than 1 in the input options.
+   */
   choices!: Choice[];
-  created!: i32; // unix timestamp seconds
-  model!: string;
 
+  /**
+   * The Unix timestamp (in seconds) of when the chat completion was created.
+   */
+  created!: i32;
+
+  /**
+   * The model used for the chat completion.
+   * In most cases, this will match the requested `model` field in the input.
+   */
+  model!: string;
 
+  /**
+   * The service tier used for processing the request.
+   *
+   * This field is only included if the `serviceTier` parameter is specified in the request.
+   */
+  @alias("service_tier")
+  serviceTier: string | null = null;
+
+  /**
+   * This fingerprint represents the OpenAI backend configuration that the model runs with.
+   *
+   * Can be used in conjunction with the seed request parameter to understand when backend changes
+   * have been made that might impact determinism.
+   */
   @alias("system_fingerprint")
   systemFingerprint!: string;
 
+  /**
+   * The usage statistics for the request.
+   */
   usage!: Usage;
 }
 
-
+/**
+ * An object specifying the format that the model must output.
+ */
 @json
 export class ResponseFormat {
-  type!: string;
-
+  /**
+   * The type of response format.  Must be one of `"text"` or `"json_object"`.
+   */
+  readonly type!: string;
+
+  /**
+   * Instructs the model to output the response as a JSON object.
+   *
+   * @remarks
+   * You must also instruct the model to produce JSON yourself via a system or user message.
+   *
+   * Additionally, if you need an array you must ask for an object that wraps the array,
+   * because the model will not reliably produce arrays directly (ie., there is no `json_array` option).
+   */
   static Json: ResponseFormat = { type: "json_object" };
+
+  /**
+   * Instructs the model to output the response as a plain text string.
+   *
+   * @remarks
+   * This is the default response format.
+   */
   static Text: ResponseFormat = { type: "text" };
 }
 
@@ -127,100 +323,231 @@ export class ResponseFormat {
 //   includeUsage: bool = false;
 // }
 
+/**
+ * A tool object that the model may call.
+ */
 @json
 export class Tool {
+  /**
+   * The type of the tool. Currently, only `"function"` is supported.
+   *
+   * @default "function"
+   */
   type: string = "function";
+
+  /**
+   * The definition of the function.
+   */
   function: FunctionDefinition = new FunctionDefinition();
 }
 
-
+/**
+ * The definition of a function that can be called by the model.
+ */
 @json
 export class FunctionDefinition {
+  /**
+   * The name of the function to be called.
+   *
+   * Must be a-z, A-Z, 0-9, or contain underscores and dashes, with a maximum length of 64.
+   */
   name!: string;
 
-
+  /**
+   * An optional description of what the function does, used by the model to choose when and how to call the function.
+   */
   @omitnull()
   description: string | null = null;
 
-
+  /**
+   * The parameters the functions accepts, described as a JSON Schema object.
+   *
+   * See https://platform.openai.com/docs/guides/function-calling
+   */
   @omitnull()
   parameters: string | null = null; // TODO: verify this works
 }
 
-
+/**
+ * A tool call object that the model may generate.
+ */
 @json
 export class ToolCall {
+  /**
+   * The ID of the tool call.
+   */
   id!: string;
+
+  /**
+   * The type of the tool. Currently, only `"function"` is supported.
+   *
+   * @default "function"
+   */
   type: string = "function";
+
+  /**
+   * The function that the model called.
+   */
   function!: FunctionCall;
 }
 
-
+/**
+ * A function call object that the model may generate.
+ */
 @json
 export class FunctionCall {
+  /**
+   * The name of the function to call.
+   */
   name!: string;
+
+  /**
+   * The arguments to call the function with, as generated by the model in JSON format.
+   *
+   * @remarks
+   * 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.
+   */
   arguments!: string;
 }
 
-
+/**
+ * The usage statistics for the request.
+ */
 @json
 class Usage {
-
+  /**
+   * The number of completion tokens used in the response.
+   */
   @alias("completion_tokens")
   completionTokens!: i32;
 
-
+  /**
+   * The number of prompt tokens used in the request.
+   */
   @alias("prompt_tokens")
   promptTokens!: i32;
 
-
+  /**
+   * The total number of tokens used in the request and response.
+   */
   @alias("total_tokens")
   totalTokens!: i32;
 }
 
-
+/**
+ * A completion choice object returned in the response.
+ */
 @json
 class Choice {
-
+  /**
+   * The reason the model stopped generating tokens.
+   *
+   * Possible values are:
+   * - `"stop"` if the model hit a natural stop point or a provided stop sequence
+   * - `"length"` if the maximum number of tokens specified in the request was reached
+   * - `"content_filter"` if content was omitted due to a flag from our content filters
+   * - `"tool_calls"` if the model called a tool
+   */
   @alias("finish_reason")
   finishReason!: string;
 
+  /**
+   * The index of the choice in the list of choices.
+   */
   index!: i32;
 
+  /**
+   * A chat completion message generated by the model.
+   */
   message!: CompletionMessage;
 
+  /**
+   * Log probability information for the choice.
+   */
   logprobs!: Logprobs | null;
 }
 
-
+/**
+ * Log probability information for a choice.
+ */
 @json
 class Logprobs {
+  /**
+   * A list of message content tokens with log probability information.
+   */
   content: LogprobsContent[] | null = null;
 }
 
-
+/**
+ * Log probability information for a message content token.
+ */
 @json
 class LogprobsContent {
+  /**
+   * The token.
+   */
   token!: string;
+
+  /**
+   * The log probability of this token, if it is within the top 20 most likely tokens.
+   * Otherwise, the value `-9999.0` is used to signify that the token is very unlikely.
+   */
   logprob!: f64;
-  bytes!: u8[] | null; // TODO: verify this works
 
+  /**
+   * A list of integers representing the UTF-8 bytes representation of the token.
+   *
+   * Useful in instances where characters are represented by multiple tokens and their byte
+   * representations must be combined to generate the correct text representation.
+   * Can be null if there is no bytes representation for the token.
+   */
+  bytes!: u8[] | null; // TODO: verify this works
 
+  /**
+   * List of the most likely tokens and their log probability, at this token position.
+   * In rare cases, there may be fewer than the number of requested `topLogprobs` returned.
+   */
   @alias("top_logprobs")
   topLogprobs!: TopLogprobsContent[]; // TODO: verify this works
 }
 
-
+/**
+ * Log probability information for the most likely tokens at a given position.
+ */
 @json
 class TopLogprobsContent {
+  /**
+   * The token.
+   */
   token!: string;
+
+  /**
+   * The log probability of this token, if it is within the top 20 most likely tokens.
+   * Otherwise, the value `-9999.0` is used to signify that the token is very unlikely.
+   */
   logprob!: f64;
+
+  /**
+   * A list of integers representing the UTF-8 bytes representation of the token.
+   * Useful in instances where characters are represented by multiple tokens and their byte
+   * representations must be combined to generate the correct text representation.
+   * Can be null if there is no bytes representation for the token.
+   */
   bytes!: u8[] | null; // TODO: verify this works
 }
 
-
+/**
+ * A message object that can be sent to the chat model.
+ */
 @json
 abstract class Message {
+  /**
+   * Creates a new message object.
+   *
+   * @param role The role of the author of this message.
+   * @param content The contents of the message.
+   */
   constructor(role: string, content: string) {
     this._role = role;
     this.content = content;
@@ -229,74 +556,133 @@ abstract class Message {
 
   @alias("role")
   protected _role: string;
+
+  /**
+   * The role of the author of this message.
+   */
   get role(): string {
     return this._role;
   }
 
+  /**
+   * The contents of the message.
+   */
   content: string;
 }
 
-
+/**
+ * A system message.
+ */
 @json
 export class SystemMessage extends Message {
+  /**
+   * Creates a new system message object.
+   *
+   * @param content The contents of the message.
+   */
   constructor(content: string) {
     super("system", content);
   }
 
-
+  /**
+   * An optional name for the participant.
+   * Provides the model information to differentiate between participants of the same role.
+   */
   @omitnull()
   name: string | null = null;
 }
 
-
+/**
+ * A user message.
+ */
 @json
 export class UserMessage extends Message {
+  /**
+   * Creates a new user message object.
+   *
+   * @param content The contents of the message.
+   */
   constructor(content: string) {
     super("user", content);
   }
 
-
+  /**
+   * An optional name for the participant.
+   * Provides the model information to differentiate between participants of the same role.
+   */
   @omitnull()
   name: string | null = null;
 }
 
-
+/**
+ * An assistant message.
+ */
 @json
 export class AssistantMessage extends Message {
+  /**
+   * Creates a new assistant message object.
+   *
+   * @param content The contents of the message.
+   */
   constructor(content: string) {
     super("assistant", content);
   }
 
-
+  /**
+   * An optional name for the participant.
+   * Provides the model information to differentiate between participants of the same role.
+   */
   @omitnull()
   name: string | null = null;
 
-
+  /**
+   * The tool calls generated by the model, such as function calls.
+   */
   @alias("tool_calls")
   @omitif("this.toolCalls.length == 0")
   toolCalls: ToolCall[] = [];
 }
 
-
+/**
+ * A tool message.
+ */
 @json
 export class ToolMessage extends Message {
-  constructor(content: string) {
+  /**
+   * Creates a new tool message object.
+   *
+   * @param content The contents of the message.
+   */
+  constructor(content: string, toolCallId: string) {
     super("tool", content);
+    this.toolCallId = toolCallId;
   }
 
-
+  /**
+   * Tool call that this message is responding to.
+   */
   @alias("tool_call_id")
   toolCallId!: string;
 }
 
-
+/**
+ * A chat completion message generated by the model.
+ */
 @json
 class CompletionMessage extends Message {
+  /**
+   * Creates a new completion message object.
+   *
+   * @param role The role of the author of this message.
+   * @param content The contents of the message.
+   */
   constructor(role: string, content: string) {
     super(role, content);
   }
 
-
+  /**
+   * The tool calls generated by the model, such as function calls.
+   */
   @alias("tool_calls")
   toolCalls: ToolCall[] = [];
 }