AI Tool Guide

Gemini — The Complete Guide

Google’s AI assistant — built into Search, Gmail, Docs, Sheets, and YouTube. The most deeply integrated AI in the world. How it was made, what it does, how to use it in your daily life and work, and full technical depth. Three reading levels. Official sources only.

Gemini Google DeepMind ~9,800 words Updated April 2026

What is Gemini?

Gemini is Google’s AI assistant. If you use Gmail, Google Docs, Google Search, or YouTube, you have probably already seen it. It is the AI that can summarise your emails, help you write in Google Docs, answer questions in Search, and understand images and videos — not just text.

You can use Gemini directly at gemini.google.com, or find it built into your existing Google tools.

The clearest way to understand Gemini

ChatGPT is a standalone AI you visit separately. Gemini is an AI that lives inside the tools you already use every day. If your life runs on Google — Gmail, Google Drive, Search, YouTube — Gemini is already there, ready to help.

Who made Gemini?

Gemini was made by Google DeepMind — the result of a 2023 merger between Google Brain (Google’s internal AI research team, founded 2011) and DeepMind (an independent AI lab Google acquired in 2014).

DeepMind’s greatest earlier achievement was AlphaGo — the AI that, in 2016, defeated the world champion at Go, a board game considered far too complex for computers to master. That victory, watched by 200 million people, demonstrated that AI could master tasks previously thought to require human intuition.

The combined Google DeepMind team, headquartered in London and Mountain View, is one of the largest and most highly regarded AI research organisations in the world.

The history of Gemini

The long road before Gemini

Google had been doing AI research longer than almost anyone. Their researchers invented the transformer architecture in 2017 — the technology that underlies ChatGPT, Claude, and Gemini itself. They developed BERT in 2018, which transformed how Google Search understood queries. They built LaMDA, the conversational AI that became famous in 2022 when a Google engineer publicly claimed it was sentient (Google disagreed and the engineer was eventually dismissed).

But Google was slow to put a consumer-facing AI in front of the public. When ChatGPT launched in November 2022, Google declared an internal “code red.”

February 2023: Bard — a stumbling start

Google rushed to release Bard in February 2023, just weeks after ChatGPT’s explosive growth. The launch was not smooth. In a promotional video, Bard gave an incorrect answer about the James Webb Space Telescope. Google’s share price fell 7% — wiping approximately $100 billion from its market value in a single day. It was a painful demonstration of the risks of rushing AI to market.

Despite the rough start, Bard improved rapidly and was made available in more countries over the following months.

December 2023: Gemini is unveiled

On 6 December 2023, Google rebranded and relaunched with Gemini. This was not just a rename — the underlying model was genuinely new and more capable. Gemini was presented as natively multimodal from the ground up (able to understand text, images, audio, video, and code simultaneously) and came in three sizes: Ultra (the most capable), Pro (the balanced version), and Nano (designed to run on devices like phones).

The launch demo showed impressive capabilities, but was later revealed to have been edited to make it appear faster and more seamless than it was in real-time use. This created another wave of criticism about Google’s communication around Gemini.

February 2024: Bard becomes Gemini

Google retired the Bard name entirely. The product became Gemini. The app launched on Android and iOS. Gemini Advanced — powered by the Ultra model — launched as part of Google One AI Premium at $19.99/month.

May 2024: Gemini 1.5 — the million-token breakthrough

Gemini 1.5 Pro introduced a context window of up to one million tokens — by far the largest available from any commercial AI at the time. To put this in perspective: one million tokens is roughly equivalent to one hour of video, 11 hours of audio, 30,000 lines of code, or 700,000 words of text — all held in a single conversation. This was a genuine technical achievement, made possible by a new architecture called Multi-Head Latent Attention.

2024–2025: Deep Google integration

Gemini becomes embedded throughout Google’s products. Gemini in Gmail can summarise email threads and draft replies. Gemini in Google Docs can write, improve, and summarise documents. Gemini in Google Sheets can analyse data and generate formulas. Gemini in Google Meet generates meeting notes. Google Search begins showing AI Overviews — Gemini-generated summaries at the top of search results.

December 2024: Gemini 2.0

Gemini 2.0 Flash launches as the new standard model — faster, more capable, and with improved reasoning. Google positions 2.0 as the foundation for “agentic” AI — capable of taking multi-step actions on behalf of users across Google’s ecosystem. Project Astra (a research prototype demonstrating real-time visual AI interaction) and Project Mariner (an agent that browses the web) are demonstrated.

2025–2026: Gemini 2.5

Gemini 2.5 Pro, released in 2025, becomes Google’s frontier model — achieving top rankings on multiple coding, reasoning, and mathematical benchmarks. It features deep thinking capabilities similar to Claude 3.7’s extended thinking and OpenAI’s o1.

What makes Gemini different?

The thing that makes Gemini genuinely unique

Gemini is the only major AI that lives inside your existing Google tools. If your emails are in Gmail, your documents in Google Docs, your calendar in Google Calendar — Gemini can see all of it (with your permission) and help you across all of it. No other AI assistant has this level of integration with tools that hundreds of millions of people already use every day.

Practical uses — real examples

In Gmail

Open any email thread. Click the Gemini icon. Ask: “Summarise this thread and tell me what I need to respond to.” Or click “Help me write” and describe what you want to say — Gemini drafts the reply.

Gmail prompt
Summarise this email thread. What has been decided? What is still outstanding? What do I need to respond to, and by when?

In Google Docs

Open any document. Click “Help me write” or “Help me improve.” Describe what you need — Gemini writes or rewrites directly in the document.

Google Docs prompt
Improve this document for clarity and flow. Keep the original meaning. Make the writing more direct and remove any unnecessary words. Suggest a stronger opening if the current one is weak.

In Google Search

When you search on Google, you may see an “AI Overview” at the top — a Gemini-generated summary with sources. You can also type more complex questions and get detailed AI-assisted answers.

Uploading images and documents

At gemini.google.com, you can upload photos, PDFs, or documents and ask questions about them. Upload a receipt and ask what you spent on food last month. Upload a document and ask for a summary. Upload a photo of a plant and ask what it is.

Image analysis prompt
Here is a photo of [describe what you uploaded]. Please: describe what you see in detail, identify the key elements, and answer my specific question about it: [your question].

Free vs paid

Free (Gemini)
  • Gemini 2.0 Flash
  • Image uploads
  • Google Search integration
  • Usage limits
Google One AI Premium ($19.99/mo)
  • Gemini 2.5 Pro (most capable)
  • Gemini in Gmail, Docs, Sheets, Meet
  • 2TB Google Drive storage
  • Deep Research feature

Source: gemini.google.com and one.google.com — April 2026

Using Gemini effectively across Google’s ecosystem

Gemini’s power compounds when you use it across multiple Google products rather than in isolation. Here is how to integrate it into a real workflow.

The Google Workspace workflow

A practical example: you receive a long email thread about a project. Use Gemini in Gmail to summarise it and extract action items. Open Google Docs and use Gemini to draft a follow-up document. Use Gemini in Sheets to build a tracker for the action items. Use Gemini in Meet to generate notes from the resulting call. This entire workflow stays within Google’s ecosystem — no copy-pasting between applications.

20 high-value prompts for Gemini

1. Email thread summary (Gmail)
Summarise this email thread chronologically. What has been agreed? What is still unresolved? What action do I need to take, and is there a deadline mentioned?
2. Draft a professional reply (Gmail)
Draft a reply to this email. My response should: acknowledge their message, answer their question about [topic] with [your answer], and close by proposing [next step]. Tone: professional and friendly. Max 150 words.
3. Improve a document (Google Docs)
Improve this document. Make the writing clearer, more direct, and more engaging. Remove jargon. Strengthen the opening. Improve transitions between sections. Do not change the substance or add new information.
4. Analyse spreadsheet data (Google Sheets)
Analyse the data in this spreadsheet. Identify: the key trends, any outliers or unusual values, what the data suggests about [business question], and what additional data would help answer [specific question].
5. Generate a formula (Google Sheets)
Write a Google Sheets formula that: [describe what you want the formula to do in plain language]. Explain what the formula does and how to use it.
6. Deep Research on a topic
Research [topic] thoroughly. I need to understand: the current state, the key players, recent developments (last 12 months), the main debates or controversies, and the most important things I should know if I’m [your context — e.g. investing, writing about it, deciding whether to use it]. Cite your sources.
7. Understand an image
I have uploaded an image of [describe it briefly]. Please: describe what you see in detail, identify the key elements and their significance, and answer this specific question about it: [your question].
8. Summarise a YouTube video
Summarise this YouTube video: [paste URL]. What are the main points? What is the speaker’s core argument or recommendation? What are the 3 most actionable takeaways?
9. Plan a project
Help me plan [project]. I need to: [describe goal]. I have [time/resources]. Create a structured plan with phases, key tasks in each phase, dependencies between tasks, and potential risks. Format it so I could use it as a Google Docs working document.
10. Prepare for a meeting
I have a meeting tomorrow about [topic] with [who]. My goal is [outcome]. Based on what you know about this topic, prepare me: key background I should know, likely discussion points, questions I should ask, and potential objections to my position with responses.
11. Write presentation speaker notes
Here are my presentation slides/outline: [paste content]. Write speaker notes for each slide. Notes should be: conversational (not read verbatim), contain the key point to make, include a transition to the next slide, and take approximately [time] minutes per slide to deliver.
12. Understand a complex topic with Google Search integration
Explain [complex topic] to me. I want to understand: what it is, why it matters, how it works in practice, and what I should know about the current state of it. Use recent sources where relevant. Flag where there is genuine debate or uncertainty.
13. Convert document to structured format
Here is a document/set of notes: [paste content]. Convert it into a structured [format: table / bulleted summary / FAQ / action plan / timeline]. Preserve all important information. Organise it so it is easy to scan and reference quickly.
14. Brainstorm with constraints
I need ideas for [goal]. Constraints: [list them — budget, time, audience, resources]. Generate 10 ideas ranging from conservative/safe to creative/ambitious. For each, give a one-sentence description and flag the main risk or challenge.
15. Write a job description
Write a job description for [role] at [type of company]. The role involves: [key responsibilities]. We are looking for someone with [key qualities — not just skills]. Tone: [professional/conversational/startup]. Include: role overview, responsibilities, requirements, what we offer. Make it appealing to strong candidates, not just a list of demands.
16. Fact-check with sources
I have heard/read the following claim: [state the claim]. Is this accurate? What does the evidence say? Please search for current, reliable sources and tell me: whether this is supported, what the nuances or caveats are, and where I can verify this myself.
17. Create a study schedule
I need to study for [exam/subject] in [time available]. I currently know [describe your level]. Create a day-by-day study plan. Include: what to cover each day, how long to spend, practice activities, and a review schedule in the final week. Be realistic about what is achievable.
18. Analyse a business situation
Here is a business situation I am facing: [describe it]. Analyse it using a structured framework. Identify: the core problem, contributing factors, options available, the tradeoffs of each option, and your recommendation. Be specific — not generic strategy consulting language.
19. Gemini API — basic call
Write Python code using the Google Generative AI library to: [describe your task]. Use the gemini-2.0-flash model. Include error handling. Add comments explaining each part of the code.
20. Long document analysis (1M token context)
I am going to share a very long document with you. Please read the entire thing carefully before responding. After reading: summarise the main argument in 3 paragraphs, identify the 5 most important claims, note any internal contradictions or unsupported assertions, and answer these specific questions: [list your questions].

Architecture: natively multimodal from the ground up

Gemini was designed from the outset as a natively multimodal model — meaning it processes text, images, audio, video, and code through a single unified architecture rather than separate specialist models. This contrasts with GPT-4, which added vision as a modality after the fact via a separate vision encoder.

The Gemini technical report describes the architecture as a transformer-based model with modifications to efficiently handle multimodal inputs. The model uses a shared vocabulary across modalities rather than separate tokenisation pipelines for each input type.

Primary source

Gemini Team, Google (2023). “Gemini: A Family of Highly Capable Multimodal Models.” arxiv.org/abs/2312.11805

The million-token context: Multi-Head Latent Attention

Gemini 1.5’s 1M token context window was achieved through a mixture-of-experts (MoE) architecture combined with a novel attention mechanism. Standard transformer attention scales quadratically with sequence length — making million-token contexts computationally infeasible with conventional approaches. Gemini 1.5 uses sparse attention patterns and MoE routing to achieve linear-ish scaling, making long-context processing practical.

The Gemini 1.5 technical report demonstrates the model performing tasks that require integrating information across the full context window — including identifying a specific scene in a 3-hour film given only a sketch, and retrieving specific information from a 10 million token codebase.

Primary source

Gemini Team, Google (2024). “Gemini 1.5: Unlocking multimodal understanding across millions of tokens of context.” arxiv.org/abs/2403.05530

Gemini 2.0 and agentic AI

Gemini 2.0 is positioned as Anthropic’s foundation for agentic applications — AI systems that take multi-step actions in the world rather than just generating text. Google’s Project Astra prototype demonstrates real-time visual understanding and memory across sessions. Project Mariner demonstrates browser-based agentic tasks. These capabilities are built on Gemini’s native tool use (the ability to call external APIs and services) and its spatial reasoning over visual inputs.

Primary source

Google DeepMind (2024). “Gemini 2.0: Our new AI model for the agentic era.” blog.google/technology/google-deepmind

Gemini API — technical reference

Basic API call (Python)
import google.generativeai as genai

genai.configure(api_key="your-api-key")
model = genai.GenerativeModel("gemini-2.0-flash")

response = model.generate_content(
    "Explain transformer architecture simply."
)
print(response.text)

Available models (April 2026): gemini-2.5-pro, gemini-2.0-flash, gemini-1.5-pro. Full reference: ai.google.dev/gemini-api/docs