AI Content Generator for Google Docs

by

Issue #2

https://github.com/lsvekis/apps-Script-Gemini-Repo

Apps Script 2Download

AI Content Generator for Google Docs

Write blog posts, lesson plans, summaries, outlines & formatted documents using Gemini — all from a custom Apps Script menu.

⭐ What You Will Build in Issue #2

A full AI Content Generator inside Google Docs with menu items like:

AI Tools

   → Generate Blog Post

   → Generate Lesson Outline

   → Generate Summary

   → Expand Highlights into Full Content

Each command opens a sidebar with a simple form where the user enters:

  • A topic
  • A style (optional)
  • A length (optional)

Gemini generates formatted content directly inside the document.

This is a writer’s copilot for Google Workspace — perfect for educators, creators, content teams, and Docs power users.

🧠 Learning Objectives

By completing this issue, you will learn:

✔ How to build HTML forms in a sidebar
✔ How to pass user input to Apps Script
✔ How to generate structured prompts for Gemini
✔ How to insert AI output directly into the Doc
✔ How to extend Apps Script menus with more powerful AI functionality
✔ How to build an AI-powered writing assistant

🧩 EXERCISE — Build the AI Content Generator

STEP 1 — Add New Menu Items

Add these to your existing onOpen() function:

function onOpen() {

  DocumentApp.getUi()

    .createMenu(“AI Tools”)

    .addItem(“Analyze Selected Text”, “showAnalyzeSidebar”)

    .addItem(“Summarize Document”, “summarizeDocument”)

    .addItem(“Rewrite for Clarity”, “rewriteForClarity”)

    .addSeparator()

    .addItem(“AI Content Generator”, “showContentGenerator”)

    .addToUi();

}

STEP 2 — Create the Sidebar UI for Content Generation

Create a new file: ContentSidebar.html

<div style=”font-family: Arial; padding: 14px;”>

  <h2>AI Content Generator</h2>

  <label>Topic</label><br/>

  <input id=”topic” style=”width: 100%; margin-bottom: 10px;” />

  <label>Style (optional, e.g., academic, friendly, professional)</label><br/>

  <input id=”style” style=”width: 100%; margin-bottom: 10px;” />

  <label>Length (optional, e.g., 200 words, 2 paragraphs)</label><br/>

  <input id=”length” style=”width: 100%; margin-bottom: 10px;” />

  <button onclick=”generate()” style=”margin-top: 10px;”>Generate</button>

  <pre id=”output” style=”white-space: pre-wrap; margin-top: 20px;”></pre>

  <script>

    function generate() {

      const topic = document.getElementById(“topic”).value;

      const style = document.getElementById(“style”).value;

      const length = document.getElementById(“length”).value;

      google.script.run.withSuccessHandler(function(result) {

        document.getElementById(“output”).textContent = result.message;

        if (result.inserted) {

          document.getElementById(“output”).textContent += “\n\n✔ Inserted into document.”;

        }

      }).generateContent(topic, style, length);

    }

  </script>

</div>

STEP 3 — Add a Function to Load the Sidebar

In Code.gs or a UI file:

function showContentGenerator() {

  const html = HtmlService.createHtmlOutputFromFile(“ContentSidebar”)

    .setTitle(“AI Content Generator”);

  DocumentApp.getUi().showSidebar(html);

}

STEP 4 — Add the Content Generation Logic

Add to GeminiHelpers.gs or a new file:

function generateContent(topic, style, length) {

  if (!topic || topic.trim() === “”)

    return { message: “Please enter a topic.”, inserted: false };

  const prompt = `

Write content based on the topic below.

Topic: ${topic}

Requirements:

– Style: ${style || “default writing style”}

– Length: ${length || “medium length”}

– Format using headings, paragraphs, and bullet points if appropriate.

– Be clear, helpful, and well-structured.

Begin:

`;

  const response = callGemini(prompt, “”);

  insertTextIntoDocument(response);

  return {

    message: “AI content generated successfully.”,

    inserted: true

  };

}

STEP 5 — Add a Utility Function to Insert AI Output into the Doc

Create a new file: InsertHelpers.gs

function insertTextIntoDocument(text) {

  const body = DocumentApp.getActiveDocument().getBody();

  body.appendParagraph(“”);

  body.appendParagraph(“=== AI Generated Content ===”)

      .setHeading(DocumentApp.ParagraphHeading.HEADING2);

  const paragraphs = text.split(“\n”);

  paragraphs.forEach(line => {

    if (line.trim() === “”) {

      body.appendParagraph(“”);

    } else {

      body.appendParagraph(line);

    }

  });

}

🧪 TESTING

  1. Reload the Google Doc
  2. Open AI Tools → AI Content Generator
  3. Enter:
    • Topic: The benefits of AI in education
    • Style: friendly and professional
    • Length: 300 words
  4. Click Generate
  5. Watch the output appear in your Doc under “=== AI Generated Content ===“

🎉 WHAT YOU BUILT IN ISSUE #2

You now have a working AI Content Generator that:

✔ Accepts user input
✔ Builds a structured prompt
✔ Sends it to Gemini
✔ Inserts formatted content directly into the document
✔ Provides a reusable framework for future content tools

This framework will be used again in Issue #3 and Issue #4 to build:

  • AI-powered Sheets tools
  • RAG systems
  • Automated workflows
  • AI assistants inside Workspace

🔥 Coming Next: Issue #3 – AI Data Analyst for Google Sheets

Ask Gemini questions about selected data ranges and get:

  • Summaries
  • Anomalies
  • Trends
  • Pivot suggestions
  • Chart recommendations
  • Plain-English explanations

Full code, UI, prompts, and setup included.

Below is a complete Apps Script setup for:

  • ✅ Issue #1 – AI Document Analyzer (sidebar)
  • ✅ Issue #2 – AI Content Generator (sidebar + inserts into Doc)
  • ✅ Includes the Gemini helper file and insert helpers

📁 Project Structure

Create these files in your Apps Script project:

  • Code.gs
  • GeminiHelpers.gs
  • Analyzer.gs
  • InsertHelpers.gs
  • (optional) SetupLessonDoc.gs
  • Sidebar.html
  • ContentSidebar.html

1️⃣ Code.gs

function onOpen() {

  DocumentApp.getUi()

    .createMenu(“AI Tools”)

    .addItem(“Analyze Selected Text”, “showAnalyzeSidebar”)

    .addItem(“Summarize Document”, “summarizeDocument”)

    .addItem(“Rewrite for Clarity”, “rewriteForClarity”)

    .addSeparator()

    .addItem(“AI Content Generator”, “showContentGenerator”)

    .addSeparator()

    .addItem(“Setup Lesson Doc (Issue #1)”, “setupLessonDoc”) // optional

    .addToUi();

}

// Sidebar for Issue #1 (AI Document Analyzer)

function showAnalyzeSidebar() {

  const html = HtmlService.createHtmlOutputFromFile(“Sidebar”)

    .setTitle(“AI Text Analyzer”);

  DocumentApp.getUi().showSidebar(html);

}

// Sidebar for Issue #2 (AI Content Generator)

function showContentGenerator() {

  const html = HtmlService.createHtmlOutputFromFile(“ContentSidebar”)

    .setTitle(“AI Content Generator”);

  DocumentApp.getUi().showSidebar(html);

}

2️⃣ GeminiHelpers.gs ✅ This is the helper you were missing

// 🔑 Replace with your real Gemini API key

const GEMINI_API_KEY = “YOUR_API_KEY_HERE”;

const GEMINI_MODEL   = “gemini-1.5-flash”; // works with v1 generateContent

/**

 * Generic helper to call Gemini’s generateContent endpoint.

 * @param {string} prompt – Instruction for the model

 * @param {string} text   – Optional content/body to include

 * @returns {string}      – Model response or error message

 */

function callGemini(prompt, text) {

  const url = `https://generativelanguage.googleapis.com/v1/models/${GEMINI_MODEL}:generateContent?key=${GEMINI_API_KEY}`;

  const payload = {

    contents: [{

      parts: [{

        text: `${prompt}${text ? “\n\n—\n\n” + text : “”}`

      }]

    }]

  };

  const options = {

    method: “post”,

    contentType: “application/json”,

    payload: JSON.stringify(payload),

    muteHttpExceptions: true

  };

  try {

    const res = UrlFetchApp.fetch(url, options);

    const status = res.getResponseCode();

    const body = res.getContentText();

    Logger.log(“Gemini status: ” + status);

    Logger.log(“Gemini body: ” + body);

    const json = JSON.parse(body);

    // Successful candidate

    if (json.candidates &&

        json.candidates[0] &&

        json.candidates[0].content &&

        json.candidates[0].content.parts &&

        json.candidates[0].content.parts[0].text) {

      return json.candidates[0].content.parts[0].text;

    }

    // API returned an error

    if (json.error) {

      return “Gemini API error: ” + json.error.message +

             (json.error.status ? ” (” + json.error.status + “)” : “”);

    }

    // Unexpected shape

    return “Unexpected Gemini response:\n” + body;

  } catch (e) {

    Logger.log(“Exception calling Gemini: ” + e);

    return “Exception calling Gemini: ” + e;

  }

}

/**

 * Quick test helper – run from Script Editor to validate setup.

 */

function testGemini() {

  const result = callGemini(

    “Summarize this in one sentence:”,

    “Google Apps Script lets you automate tasks across Google Workspace.”

  );

  Logger.log(“Test result:\n” + result);

}

3️⃣ Analyzer.gs (Issue #1 logic)

/**

 * Called from Sidebar.html → analyzeSelectedText button

 * Returns analysis string to display in the sidebar.

 */

function analyzeSelectedText() {

  const doc = DocumentApp.getActiveDocument();

  const selection = doc.getSelection();

  if (!selection) return “No text selected.”;

  let text = “”;

  selection.getRangeElements().forEach(el => {

    const element = el.getElement();

    if (element.editAsText) {

      text += element.asText().getText() + “\n”;

    }

  });

  const prompt = `

You are an expert writing assistant.

Analyze the following text and provide:

1. Key insights (bullet points)

2. A concise summary (3–5 bullet points)

3. Suggested improvements

4. Overall sentiment

5. A clearer rewrite

Respond in a clean, readable format.

`;

  return callGemini(prompt, text);

}

/**

 * Summarize the entire document. Called from Sidebar.html.

 */

function summarizeDocument() {

  const bodyText = DocumentApp.getActiveDocument().getBody().getText();

  const prompt = “Summarize the following document in 5–7 bullet points:”;

  return callGemini(prompt, bodyText);

}

/**

 * Rewrite the entire document for clarity. Called from Sidebar.html.

 */

function rewriteForClarity() {

  const bodyText = DocumentApp.getActiveDocument().getBody().getText();

  const prompt = `

Rewrite the document for clarity, conciseness, and readability.

Preserve the original meaning but improve structure and flow.

`;

  return callGemini(prompt, bodyText);

}

4️⃣ InsertHelpers.gs (shared for Issue #2 and future)

/**

 * Append AI output to the end of the document,

 * with a heading marker above it.

 */

function insertTextIntoDocument(text) {

  const body = DocumentApp.getActiveDocument().getBody();

  body.appendParagraph(“”);

  body.appendParagraph(“=== AI Generated Content ===”)

      .setHeading(DocumentApp.ParagraphHeading.HEADING2);

  const paragraphs = text.split(“\n”);

  paragraphs.forEach(line => {

    if (line.trim() === “”) {

      body.appendParagraph(“”);

    } else {

      body.appendParagraph(line);

    }

  });

}

5️⃣ Issue #2 logic – add to GeminiHelpers.gs or a new ContentGenerator.gs

/**

 * Generate AI content based on topic, style, and length from the sidebar.

 * Returns an object consumed by ContentSidebar.html.

 */

function generateContent(topic, style, length) {

  if (!topic || topic.trim() === “”) {

    return { message: “Please enter a topic.”, inserted: false };

  }

  const prompt = `

You are an expert content writer.

Write content based on the topic below.

Topic: ${topic}

Requirements:

– Style: ${style || “neutral, informative, and clear”}

– Length: ${length || “medium length”}

– Use headings, paragraphs, and bullet points when appropriate.

– Be structured, helpful, and easy to scan.

Begin the final content directly.

`;

  const response = callGemini(prompt, “”);

  insertTextIntoDocument(response);

  return {

    message: “AI content generated successfully.”,

    inserted: true

  };

}

6️⃣ SetupLessonDoc.gs (optional, from earlier)

function setupLessonDoc() {

  const doc = DocumentApp.getActiveDocument();

  const body = doc.getBody();

  // Clear existing content

  body.clear();

  // Title

  body.appendParagraph(“Apps Script + Gemini Mastery — Issue #1”)

      .setHeading(DocumentApp.ParagraphHeading.HEADING1);

  body.appendParagraph(“Your First AI-Powered Script: Build a Smart Document Analyzer”)

      .setHeading(DocumentApp.ParagraphHeading.HEADING2);

  body.appendParagraph(

    “This document was generated by the setup script. Use it as your working file ” +

    “to test the AI Tools menu connected to Gemini.”

  );

  body.appendParagraph(“”);

  // Section: What You Will Build

  body.appendParagraph(“What You Will Build”)

      .setHeading(DocumentApp.ParagraphHeading.HEADING2);

  body.appendParagraph(

    “In this lesson, you will build an AI-powered Document Analyzer for Google Docs. ” +

    “You will be able to select text and then run AI Tools → Analyze Selected Text ” +

    “to get insights, summaries, and rewrite suggestions from Gemini.”

  );

  // Section: Instructions

  body.appendParagraph(“How to Use This Doc with the AI Tools Menu”)

      .setHeading(DocumentApp.ParagraphHeading.HEADING2);

  body.appendListItem(“Select any paragraph or section of text below.”)

      .setGlyphType(DocumentApp.GlyphType.BULLET);

  body.appendListItem(“Open the menu: AI Tools → Analyze Selected Text.”)

      .setGlyphType(DocumentApp.GlyphType.BULLET);

  body.appendListItem(“Review the output in the sidebar.”)

      .setGlyphType(DocumentApp.GlyphType.BULLET);

  body.appendListItem(“Experiment with Summarize Document and Rewrite for Clarity.”)

      .setGlyphType(DocumentApp.GlyphType.BULLET);

  body.appendParagraph(“”);

  // Sample content

  body.appendParagraph(“Sample Article for AI Analysis”)

      .setHeading(DocumentApp.ParagraphHeading.HEADING2);

  const sampleParagraphs = [

    “Most teams struggle to turn raw information into clear, usable knowledge. ” +

      “Documents grow longer, feedback gets buried in email threads, and important ” +

      “decisions are scattered across chats and comments.”,

    “AI-powered tools like Gemini can help by quickly summarizing long documents, ” +

      “highlighting key decisions, and suggesting better ways to express ideas. ” +

      “Instead of manually rewriting paragraphs, you can focus on thinking and ” +

      “strategy while the AI handles structure and phrasing.”,

    “However, AI only becomes truly powerful when it is integrated into your existing workflow. ” +

      “That is why Google Apps Script is such a valuable layer: it lets you bring Gemini ” +

      “directly into Docs, Sheets, Slides, and Gmail, automating the tasks you already do ” +

      “every day.”,

    “In this lesson, you will experiment with an AI Document Analyzer that you can customize. ” +

      “Try selecting different sections of this article and see how the AI changes its ” +

      “summary, insights, and suggestions based on what you highlight.”

  ];

  sampleParagraphs.forEach(text => body.appendParagraph(text));

  body.appendParagraph(“”);

  body.appendParagraph(“Longer Sample Section”)

      .setHeading(DocumentApp.ParagraphHeading.HEADING3);

  body.appendParagraph(

    “Imagine you are responsible for reviewing weekly project reports from multiple ” +

    “teams. Each report is several pages long, combining metrics, narrative updates, ” +

    “risks, and next steps. Reading every word is unrealistic, but skipping sections ” +

    “means missing important context. With an embedded AI assistant, you can highlight ” +

    “a section and instantly ask for a concise summary, a list of risks, or a clearer ” +

    “rewrite that you can paste into your own executive update.”

  );

  body.appendParagraph(

    “This is the type of workflow enhancement that Apps Script + Gemini makes possible. ” +

    “As you test the AI Tools menu on this document, think about the documents you ” +

    “work with every day: course outlines, project charters, meeting notes, or client ” +

    “proposals. Any place where you read, summarize, and rewrite text is an opportunity ” +

    “to add intelligence with just a few lines of code.”

  );

  body.appendParagraph(“”);

  body.appendParagraph(“✅ Setup complete. You can now experiment with the AI Tools menu on this content.”);

}

7️⃣ Sidebar.html (Issue #1 UI)

<div style=”font-family: Arial; padding: 10px;”>

  <h2>AI Document Analyzer</h2>

  <button onclick=”run(‘analyzeSelectedText’)”>Analyze Selected Text</button>

  <button onclick=”run(‘summarizeDocument’)” style=”margin-left: 4px;”>Summarize Document</button>

  <button onclick=”run(‘rewriteForClarity’)” style=”margin-left: 4px;”>Rewrite for Clarity</button>

  <pre id=”output” style=”white-space: pre-wrap; margin-top: 20px;”></pre>

  <script>

    function run(fn) {

      document.getElementById(“output”).textContent = “Running ” + fn + “…”;

      google.script.run

        .withSuccessHandler(function(result) {

          document.getElementById(“output”).textContent = result;

        })

        [fn]();

    }

  </script>

</div>

8️⃣ ContentSidebar.html (Issue #2 UI)

<div style=”font-family: Arial; padding: 14px;”>

  <h2>AI Content Generator</h2>

  <label>Topic</label><br/>

  <input id=”topic” style=”width: 100%; margin-bottom: 10px;” />

  <label>Style (optional, e.g., academic, friendly, professional)</label><br/>

  <input id=”style” style=”width: 100%; margin-bottom: 10px;” />

  <label>Length (optional, e.g., 200 words, 2 paragraphs)</label><br/>

  <input id=”length” style=”width: 100%; margin-bottom: 10px;” />

  <button onclick=”generate()” style=”margin-top: 10px;”>Generate</button>

  <pre id=”output” style=”white-space: pre-wrap; margin-top: 20px;”></pre>

  <script>

    function generate() {

      const topic  = document.getElementById(“topic”).value;

      const style  = document.getElementById(“style”).value;

      const length = document.getElementById(“length”).value;

      document.getElementById(“output”).textContent = “Generating content…”;

      google.script.run

        .withSuccessHandler(function(result) {

          document.getElementById(“output”).textContent = result.message +

            (result.inserted ? “\n\n✔ Inserted into document.” : “”);

        })

        .generateContent(topic, style, length);

    }

  </script>

</div>