Google's Gemini 3 Deep Think just opened up to everyone via API and it's a different kind of AI tool. Unlike standard AI that responds immediately, Deep Think spends time reasoning through a problem before it answers.
It considers multiple hypotheses, checks its own logic, and flags where it's uncertain. This week it solved 18 previously unsolved academic research problems and caught an error in a peer-reviewed paper that human reviewers had missed.
For business use, that means it's less "quick answer tool" and more "serious research assistant." Here's how to use it.
What You'll Need
Google AI Ultra subscription ($249.99/month) for app access, or
A Google AI Studio account (free tier available) for API access
A clear research question or document to analyse
Around 3–5 minutes per query (Deep Think takes longer than standard AI, that's the point)
Step 1: Access Gemini Deep Think
Via the Gemini App (easiest):
Go to gemini.google.com and sign in. As of time of writing, you need Google AI Ultra ($249.99/month) for the app version. In the model selector at the top of the page, choose Gemini 3 Deep Think from the dropdown.
Via Google AI Studio (free to try):
Go to aistudio.google.com and create a free account. In the top right, click the model dropdown and select Gemini 3 Deep Think.
Via API (for developers and teams):
If you want to integrate Deep Think into your own tools or workflows, it's now available through the Gemini API. Access it with the model ID documentation at ai.google.dev.
Note: Deep Think is also rolling out to Google AI Ultra subscribers on mobile, but full availability may vary by region. The web app version is the most reliable starting point.
Step 2: Understand How It Thinks Differently
It helps to know what Deep Think is actually doing, because it changes how you should prompt it.
Standard AI generates a response immediately. Deep Think activates what Google calls "extended thinking". It works through a problem step by step before replying. You'll see a "Thinking..." indicator while it reasons.
What this means practically:
It's slower. Expect 2–5 minutes for complex questions, not seconds.
It shows its work. You can expand the reasoning section to see how it arrived at its answer.
It flags uncertainty. When Deep Think isn't confident, it says so instead of guessing confidently.
It's better for complex questions. Simple lookups don't need Deep Think. Save it for analysis, comparisons, and research that requires weighing multiple factors.
Step 3: Ask Your Research Question
Deep Think works best when your question is specific and has multiple layers to it. Vague questions get vague answers. This is true even for the most capable AI.
Structure your prompts like this:
I'm researching [topic] for [specific purpose].
Here's my context: [2-3 sentences about what you know or what you're trying to decide].
Question: [Your specific question].
Format: [How you want the answer structured — bullet points, table, summary, etc.]Example for competitive research:
I'm evaluating whether to enter the project management software market.
Context: We're a B2B SaaS company with 50 employees, strong in CRM, and our clients often request project tracking features.
Question: What are the main risks and opportunities in the project management software market for a company our size entering in 2026?
Format: A balanced analysis with key risks, opportunities, and a recommendation.Example for document review:
I'm reviewing a business proposal before signing. Here is the full document: [paste document].
Question: What are the key risks, unclear terms, and anything I should push back on before agreeing?
Format: Numbered list of concerns, most important first.Step 4: Read the Reasoning, Not Just the Answer
This is the step most people skip, but is where Deep Think earns its value.
After the response loads, look for the "Show thinking" or "View reasoning" panel above the answer. Click to expand it.
The reasoning section shows you how Deep Think worked through the problem: what it considered, what it ruled out, and where it was uncertain. For business decisions, this is often more valuable than the final answer because you can see the logic and catch where it made assumptions.
What to look for in the reasoning:
Does it acknowledge trade-offs your question didn't mention?
Does it flag anything it couldn't verify or wasn't confident about?
Did it consider angles you hadn't thought of?
If the reasoning reveals a gap or assumption, ask a follow-up to probe it:
You mentioned [assumption] in your reasoning. Can you explain that further and tell me what would need to be true for that assumption to be wrong?Step 5: Iterate and Go Deeper
Deep Think handles follow-up questions well because it maintains context across the conversation. Once you have an initial answer, push it further.
Useful follow-up prompts:
What's the strongest argument against this conclusion?You said [X]. What evidence would change that view?Can you pressure-test the main recommendation? What's most likely to go wrong?Summarise the key takeaways in three bullet points for an executive who hasn't seen the full analysis.What would you need to know to be more confident in this answer?The last one is particularly useful. Tt tells you exactly what research you should do next.
Practical Workflows for Business
Competitor Analysis
Deep Think is better than standard AI for competitive research because it considers multiple dimensions at once rather than listing surface-level facts.
Try this:
Analyse [Competitor Name] as a competitive threat.
Context: We sell [product] to [customer type]. They recently [relevant news or development].
Question: What are their genuine strengths, where are they vulnerable, and how should we position against them?
Format: Strengths, weaknesses, positioning recommendations.Give it competitor websites, press releases, or product pages to read if you can paste them in. The richer the input, the more specific the analysis.
Market Research Before a Decision
Before entering a new market, launching a product, or making a hire, use Deep Think to stress-test your assumptions.
Try this:
I'm considering [decision — launching a product, hiring a head of sales, expanding to a new market].
Here's my current thinking: [2-3 sentences on why you're leaning toward yes].
Question: What am I missing? What are the most common failure modes for this type of decision, and how do I know if I'm in one?This works well because you're explicitly asking Deep Think to challenge your existing view which is where it adds the most value.
Document Review and Risk Spotting
Deep Think is strong at finding logical gaps, unclear terms, and risks in documents the same thing that made it useful enough for a Rutgers mathematician to use on peer-reviewed physics papers.
Try this:
Review this document and tell me:
1. What are the key risks or concerns I should raise before agreeing to this?
2. Are there any terms or commitments that are vague or could be interpreted against my interests?
3. What's missing that should be in here?
[Paste document]Works well for: vendor contracts, partnership proposals, investor term sheets, policy documents, or any document where you need a second opinion before signing.
Strategic Planning and Scenario Analysis
Use Deep Think to map out scenarios before a major decision. Pricing changes, new product lines, restructuring, market expansion.
Try this:
We're considering [strategic change].
Our current situation: [brief description of company, revenue, team size, market].
Question: Walk me through three scenarios — best case, most likely, and worst case — and tell me what would need to be true for each one to happen.
Format: Three scenarios with triggers, key risks, and what to watch for.What Deep Think Is Not Great For
Quick lookups: If you need a fact, a date, or a simple definition, standard Gemini is faster. Save Deep Think for complex, multi-layered questions.
Real-time data: Deep Think doesn't have live internet access by default. For current pricing, recent news, or live market data, enable web search first.
High-volume tasks: The slower response time makes it impractical for tasks you need to repeat at scale. Use standard models for those.
Real-World Use Cases
Marketing and Strategy Teams: Analyse campaign performance against competitors, review messaging for logical consistency, stress-test go-to-market plans before launch.
Sales Teams: Research prospects and accounts before calls, analyse deal losses to find patterns, review proposals for gaps before sending.
Founders and Executives: Pressure-test business plans, analyse market sizing assumptions, review investor materials for weaknesses.
Finance and Operations: Review vendor contracts for risk, analyse budget proposals, stress-test financial projections before board presentations.
Consultants and Agencies: Conduct preliminary research before client projects, review client-provided documents for issues, validate analysis and recommendations before presenting.
Tips for Better Results
Give context, not just questions. Deep Think performs significantly better when it knows why you're asking. "What are the risks of this contract?" gets a generic answer. "What are the risks of this contract for a 30-person SaaS company trying to protect our IP?" gets a focused one.
Paste in your documents. Deep Think can read long documents in full, up to 1 million tokens. Instead of summarising a report yourself, paste it in and let Deep Think analyse it directly.
Ask it to disagree with you. The most useful thing Deep Think does is challenge assumptions. Explicitly ask it to steelman the opposite view or find the flaw in your reasoning.
Don't rush the thinking time. The 2–5 minute wait is the feature, not a bug. It's doing more work than standard AI. Read the reasoning panel while you wait to understand what it's working through.
Common Questions
Is Deep Think worth the cost for a small business? At $249.99/month for AI Ultra, it's a significant investment. The access via Google AI Studio is a sensible way to test it before committing. If you regularly make decisions involving competitive analysis, contracts, or strategic planning, the cost can be justified quickly.
How is it different from using ChatGPT or Claude for research? All frontier AI models can do research. Deep Think's differentiator is the extended reasoning mode, it considers more angles and checks its logic before responding. On benchmarks requiring complex reasoning, it currently leads. Try a few with the same question and compare.
Can I use it for confidential business documents? Your inputs are processed on Google's servers. Review Google's data usage policies and your company's AI guidelines before pasting confidential documents. For highly sensitive material, check whether your organisation has an enterprise agreement with Google.
Next Steps
Start with a decision you're currently weighing or a document sitting in your inbox that needs a second opinion. Paste the context in, ask Deep Think to tell you what you're missing, and read the reasoning panel, not just the answer.
The most productive way to use it isn't as a search engine replacement. It's as a thinking partner for the moments where you want to stress-test your logic before committing to something.
Start with these tasks:
Analyse a competitor you've been meaning to research properly
Review a vendor contract or proposal before signing
Pressure-test a business decision you're about to make
Get a second opinion on a strategy document or pitch
I don’t think you should outsource your thinking. Gemini 3 Deep Think is here to catch what you'd otherwise miss and go deeper in thinking than you would have otherwise been able to do on your own.