diff --git a/cookbooks/Function-Calling-OpenAI/typescript/function-calling-with-openai.ts b/cookbooks/Function-Calling-OpenAI/typescript/function-calling-with-openai.ts
index b7f3a5d7b..b2943d413 100644
--- a/cookbooks/Function-Calling-OpenAI/typescript/function-calling-with-openai.ts
+++ b/cookbooks/Function-Calling-OpenAI/typescript/function-calling-with-openai.ts
@@ -1,4 +1,4 @@
-import { AIConfigRuntime, ExecuteResult } from "aiconfig";
+import { AIConfigRuntime, ExecuteResult, Prompt } from "aiconfig";
 import { Chat } from "openai/resources";
 
 const BOOKS_DB = [
@@ -131,11 +131,15 @@ async function main() {
   };
 
   // Add the prompt
-  let newPrompts = await config.serialize(model, data, "recommend_book", {
-    book: "To Kill a Mockingbird",
-  });
-  let newPrompt = Array.isArray(newPrompts) ? newPrompts[0] : newPrompts;
-  config.addPrompt(newPrompt);
+  let newPrompts: Prompt[] = await config.serialize(
+    model,
+    data,
+    "recommend_book",
+    {
+      book: "To Kill a Mockingbird",
+    }
+  );
+  config.addPrompt(newPrompts[0]);
 
   const params = { book: "Where the Crawdads Sing" };
   const inferenceOptions = {
@@ -194,8 +198,7 @@ async function main() {
   };
 
   newPrompts = await config.serialize(model, promptData, "gen_summary");
-  newPrompt = Array.isArray(newPrompts) ? newPrompts[0] : newPrompts;
-  config.addPrompt(newPrompt);
+  config.addPrompt(newPrompts[0]);
 
   await config.run("gen_summary", { book_info: value }, inferenceOptions);
 }
diff --git a/cookbooks/HuggingFace/typescript/hf.ts b/cookbooks/HuggingFace/typescript/hf.ts
index 697d89836..53fc96b02 100644
--- a/cookbooks/HuggingFace/typescript/hf.ts
+++ b/cookbooks/HuggingFace/typescript/hf.ts
@@ -45,7 +45,7 @@ export class HuggingFaceTextGenerationModelParser extends aiconfig.Parameterized
     data: TextGenerationArgs,
     aiConfig: AIConfigRuntime,
     params?: JSONObject | undefined
-  ): Prompt | Prompt[] {
+  ): Prompt[] {
     const input: PromptInput = data.inputs;
 
     let modelMetadata: ModelMetadata | string;
diff --git a/extensions/HuggingFace/typescript/hf.ts b/extensions/HuggingFace/typescript/hf.ts
index 89bb283ef..cf25f8674 100644
--- a/extensions/HuggingFace/typescript/hf.ts
+++ b/extensions/HuggingFace/typescript/hf.ts
@@ -47,7 +47,7 @@ export class HuggingFaceTextGenerationModelParserExtension extends Parameterized
     data: TextGenerationArgs,
     aiConfig: AIConfigRuntime,
     params?: JSONObject | undefined
-  ): Prompt | Prompt[] {
+  ): Prompt[] {
     const startEvent = {
       name: "on_serialize_start",
       file: __filename,
diff --git a/extensions/llama/typescript/llama.ts b/extensions/llama/typescript/llama.ts
index 3df085e95..cec9f3b5e 100644
--- a/extensions/llama/typescript/llama.ts
+++ b/extensions/llama/typescript/llama.ts
@@ -105,7 +105,7 @@ export class LlamaModelParser extends ParameterizedModelParser<LlamaCompletionPa
     data: LlamaCompletionParams,
     aiConfig: AIConfigRuntime,
     params?: JSONObject | undefined
-  ): Prompt | Prompt[] {
+  ): Prompt[] {
     const startEvent = {
       name: "on_serialize_start",
       file: __filename,
@@ -126,7 +126,7 @@ export class LlamaModelParser extends ParameterizedModelParser<LlamaCompletionPa
       completionParams.model
     );
 
-    let prompts: Prompt[] = [];
+    const prompts: Prompt[] = [];
 
     if (conversationHistory && conversationHistory.length > 0) {
       let i = 0;
@@ -153,7 +153,7 @@ export class LlamaModelParser extends ParameterizedModelParser<LlamaCompletionPa
       }
     }
 
-    const prompt: Prompt = {
+    const newPrompt: Prompt = {
       name: promptName,
       input,
       metadata: {
@@ -162,23 +162,16 @@ export class LlamaModelParser extends ParameterizedModelParser<LlamaCompletionPa
         remember_chat_context: (conversationHistory?.length ?? 0) > 0,
       },
     };
-
-    let result: Prompt | Prompt[] = prompt;
-    if (prompts.length > 0) {
-      prompts.push(prompt);
-      result = prompts;
-    }
+    prompts.push(newPrompt);
 
     const endEvent = {
       name: "on_serialize_end",
       file: __filename,
-      data: {
-        result,
-      },
+      data: { prompts },
     };
     aiConfig.callbackManager.runCallbacks(endEvent);
 
-    return result;
+    return prompts;
   }
 
   public refineCompletionParams(
diff --git a/typescript/__tests__/config.test.ts b/typescript/__tests__/config.test.ts
index 07950822e..1a6c57c1c 100644
--- a/typescript/__tests__/config.test.ts
+++ b/typescript/__tests__/config.test.ts
@@ -123,7 +123,7 @@ describe("Loading an AIConfig", () => {
       ],
     });
 
-    const serializeResult = await aiConfig.serialize(
+    const prompts: Prompt[] = await aiConfig.serialize(
       "gpt-3.5-turbo",
       completionParams,
       "prompt",
@@ -132,10 +132,6 @@ describe("Loading an AIConfig", () => {
       }
     );
 
-    expect(Array.isArray(serializeResult)).toBe(true);
-
-    const prompts: Prompt[] = serializeResult as Prompt[];
-
     expect(prompts.length).toBe(2);
 
     const prompt1 = prompts[0];
@@ -177,7 +173,7 @@ describe("Loading an AIConfig", () => {
       ],
     };
 
-    const serializeResult = await aiConfig.serialize(
+    const prompts: Prompt[] = await aiConfig.serialize(
       "gpt-3.5-turbo",
       completionParams,
       "prompt",
@@ -186,10 +182,6 @@ describe("Loading an AIConfig", () => {
       }
     );
 
-    expect(Array.isArray(serializeResult)).toBe(true);
-
-    const prompts: Prompt[] = serializeResult as Prompt[];
-
     expect(prompts.length).toBe(2);
 
     const prompt1 = prompts[0];
diff --git a/typescript/__tests__/parsers/hf/hf.test.ts b/typescript/__tests__/parsers/hf/hf.test.ts
index ed3dd1c51..26ecda8d6 100644
--- a/typescript/__tests__/parsers/hf/hf.test.ts
+++ b/typescript/__tests__/parsers/hf/hf.test.ts
@@ -126,11 +126,11 @@ describe("HuggingFaceTextGeneration ModelParser", () => {
       inputs: "What are 5 interesting things to do in Toronto?",
     };
 
-    const prompts = parser.serialize(
+    const prompts: Prompt[] = parser.serialize(
       "interestingThingsToronto",
       completionParams,
       aiConfig
-    ) as Prompt[];
+    );
 
     expect(prompts).toHaveLength(1);
     const prompt = prompts[0];
@@ -165,11 +165,11 @@ describe("HuggingFaceTextGeneration ModelParser", () => {
     const callbackManager = new CallbackManager([callback]);
     aiConfig.setCallbackManager(callbackManager);
 
-    const prompts = parser.serialize(
+    const prompts: Prompt[] = parser.serialize(
       "interestingThingsToronto",
       completionParams,
       aiConfig
-    ) as Prompt[];
+    );
 
     const onStartEvent = callback.mock.calls[0][0];
     expect(onStartEvent.name).toEqual("on_serialize_start");
diff --git a/typescript/__tests__/parsers/palm-text/palm.test.ts b/typescript/__tests__/parsers/palm-text/palm.test.ts
index cdbffe309..89ca8003a 100644
--- a/typescript/__tests__/parsers/palm-text/palm.test.ts
+++ b/typescript/__tests__/parsers/palm-text/palm.test.ts
@@ -38,11 +38,11 @@ describe("PaLM Text ModelParser", () => {
       };
 
     // Casting as JSONObject since the type of completionParams is protos.google.ai.generativelanguage.v1beta2.IGenerateTextRequest doesn't confrom to shape even though it looks like it does
-    const prompts = (await aiConfig.serialize(
+    const prompts: Prompt[] = await aiConfig.serialize(
       "models/text-bison-001",
       completionParams as JSONObject,
       "interestingThingsToronto"
-    )) as Prompt[];
+    );
 
     expect(prompts).toHaveLength(1);
     const prompt = prompts[0];
diff --git a/typescript/demo/demo.ts b/typescript/demo/demo.ts
index 0417431d1..994d51c06 100644
--- a/typescript/demo/demo.ts
+++ b/typescript/demo/demo.ts
@@ -4,6 +4,7 @@ import OpenAI from "openai";
 import * as path from "path";
 import { AIConfigRuntime } from "../lib/config";
 import { InferenceOptions } from "../lib/modelParser";
+import { Prompt } from "../types";
 
 // This example is taken from https://github.com/openai/openai-node/blob/v4/examples/demo.ts
 // and modified to show the same functionality using AIConfig.
@@ -104,14 +105,10 @@ async function createAIConfig() {
   };
 
   const aiConfig = AIConfigRuntime.create("demo", "this is a demo AIConfig");
-  const result = await aiConfig.serialize(model, data, "demoPrompt");
+  const prompts: Prompt[] = await aiConfig.serialize(model, data, "demoPrompt");
 
-  if (Array.isArray(result)) {
-    for (const prompt of result) {
-      aiConfig.addPrompt(prompt);
-    }
-  } else {
-    aiConfig.addPrompt(result);
+  for (const prompt of prompts) {
+    aiConfig.addPrompt(prompt);
   }
 
   aiConfig.save("demo/demo.aiconfig.json", { serializeOutputs: true });
diff --git a/typescript/demo/function-call-stream.ts b/typescript/demo/function-call-stream.ts
index fbd427a4d..b4ae19033 100644
--- a/typescript/demo/function-call-stream.ts
+++ b/typescript/demo/function-call-stream.ts
@@ -289,14 +289,14 @@ async function createAIConfig() {
     "function-call-demo",
     "this is a demo AIConfig to show function calling using OpenAI"
   );
-  const result = await aiConfig.serialize(model, data, "functionCallResult");
+  const prompts: Prompt[] = await aiConfig.serialize(
+    model,
+    data,
+    "functionCallResult"
+  );
 
-  if (Array.isArray(result)) {
-    for (const prompt of result) {
-      aiConfig.addPrompt(prompt);
-    }
-  } else {
-    aiConfig.addPrompt(result);
+  for (const prompt of prompts) {
+    aiConfig.addPrompt(prompt);
   }
 
   aiConfig.save("demo/function-call.aiconfig.json", {
diff --git a/typescript/demo/test-hf.ts b/typescript/demo/test-hf.ts
index 466646d5a..d29ef1d1a 100644
--- a/typescript/demo/test-hf.ts
+++ b/typescript/demo/test-hf.ts
@@ -23,11 +23,11 @@ async function run() {
   console.log("Latest output: ", config.getOutputText("prompt1"));
 
   console.log("serialize prompt2: ");
-  const prompts = (await config.serialize(
+  const prompts: Prompt[] = await config.serialize(
     "mistralai/Mistral-7B-v0.1",
     { inputs: "Hello, world!" },
     "prompt2"
-  )) as Prompt[];
+  );
 
   const prompt2 = prompts[0];
 
diff --git a/typescript/lib/config.ts b/typescript/lib/config.ts
index 4baab769a..1ce06ebfa 100644
--- a/typescript/lib/config.ts
+++ b/typescript/lib/config.ts
@@ -360,7 +360,7 @@ export class AIConfigRuntime implements AIConfig {
     data: JSONObject,
     promptName: string,
     params?: JSONObject
-  ): Promise<Prompt | Prompt[]> {
+  ): Promise<Prompt[]> {
     const startEvent = {
       name: "on_serialize_start",
       file: __filename,
@@ -376,7 +376,12 @@ export class AIConfigRuntime implements AIConfig {
       );
     }
 
-    const prompts = modelParser.serialize(promptName, data, this, params);
+    const prompts: Prompt[] = modelParser.serialize(
+      promptName,
+      data,
+      this,
+      params
+    );
     const endEvent = {
       name: "on_serialize_end",
       file: __filename,
diff --git a/typescript/lib/modelParser.ts b/typescript/lib/modelParser.ts
index 25e320319..92943c371 100644
--- a/typescript/lib/modelParser.ts
+++ b/typescript/lib/modelParser.ts
@@ -62,7 +62,7 @@ export abstract class ModelParser<T = JSONObject, R = T> {
     data: T,
     aiConfig: AIConfigRuntime,
     params?: JSONObject
-  ): Prompt | Prompt[];
+  ): Prompt[];
 
   /**
    * Deserialize a Prompt object loaded from an AIConfig into a structure that can be used for model inference.
diff --git a/typescript/lib/parsers/hf.ts b/typescript/lib/parsers/hf.ts
index 8bebae787..cd8712967 100644
--- a/typescript/lib/parsers/hf.ts
+++ b/typescript/lib/parsers/hf.ts
@@ -39,7 +39,7 @@ export class HuggingFaceTextGenerationParser extends ParameterizedModelParser<Te
     data: TextGenerationArgs,
     aiConfig: AIConfigRuntime,
     params?: JSONObject | undefined
-  ): Prompt | Prompt[] {
+  ): Prompt[] {
     const startEvent = {
       name: "on_serialize_start",
       file: __filename,
diff --git a/typescript/lib/parsers/openai.ts b/typescript/lib/parsers/openai.ts
index 22f9d466b..d13d14f31 100644
--- a/typescript/lib/parsers/openai.ts
+++ b/typescript/lib/parsers/openai.ts
@@ -40,7 +40,7 @@ export class OpenAIModelParser extends ParameterizedModelParser<CompletionCreate
     data: CompletionCreateParams,
     aiConfig: AIConfigRuntime,
     params?: JSONObject
-  ): Prompt {
+  ): Prompt[] {
     // Serialize prompt input
     let input: PromptInput;
     if (typeof data.prompt === "string") {
@@ -105,7 +105,7 @@ export class OpenAIModelParser extends ParameterizedModelParser<CompletionCreate
       },
     };
 
-    return prompt;
+    return [prompt];
   }
 
   public deserialize(
diff --git a/typescript/lib/parsers/palm.ts b/typescript/lib/parsers/palm.ts
index 1fcca60e4..214b7f965 100644
--- a/typescript/lib/parsers/palm.ts
+++ b/typescript/lib/parsers/palm.ts
@@ -35,7 +35,7 @@ export class PaLMTextParser extends ParameterizedModelParser {
     data: JSONObject,
     aiConfig: AIConfigRuntime,
     params?: JSONObject | undefined
-  ): Prompt | Prompt[] {
+  ): Prompt[] {
     const startEvent = {
       name: "on_serialize_start",
       file: __filename,