Deep research is an AI feature that spends several minutes searching the web, reading many sources and writing a detailed, cited report in response to one question. Instead of a quick paragraph, a buyer who asks "Compare the top commercial roofing contractors in Denver for a 20,000-square-foot warehouse" might get a multi-page report with pricing factors, contractor comparisons and links to every source used.
For businesses, deep research matters because it is how many buyers now do serious homework before a big purchase. A deep research report can read dozens or hundreds of pages, so it reaches further than a normal search. If your site clearly answers the detailed questions buyers ask, it has a better chance of being one of the sources the report relies on and links to.
What is deep research?
Deep research is a type of AI agent that carries out multi-step research on its own. You give it a question, and it plans a series of searches, reads the results, decides what to look up next and writes a structured report with citations. Several major AI platforms offer a version:
- Gemini Deep Research: Google announced it on December 11, 2024. Gemini drafts a multi-step research plan that you can revise or approve, then searches and reads for a few minutes and produces a report with links to sources. Reports can be exported to Google Docs.
- ChatGPT deep research: OpenAI launched it on February 2, 2025. OpenAI said it finds, analyzes and synthesizes hundreds of online sources, takes about 5 to 30 minutes and cites each claim.
- Perplexity Deep Research: launched February 15, 2025. Perplexity said it iteratively searches, reads documents and reasons about what to do next, with most tasks finishing in under three minutes.
Google has also added Deep Search to AI Mode. Announced at Google I/O in May 2025 and rolled out that July, Google said it runs hundreds of searches and reasons across the results to create a fully cited report.
Why deep research matters
It is built for high-stakes decisions. People use deep research when the answer matters: choosing a vendor, comparing software, planning a large purchase or researching a market. These are often the buyers a business most wants to reach.
It reads more of the web. OpenAI says its agent works through hundreds of online sources for a single request, far more than a quick answer has time for. That gives detailed, specific pages a chance to be cited even if they don't rank first in traditional search. Each source can become an AI citation in the final report.
It rewards depth and evidence. Deep research is powered by reasoning models. OpenAI said its agent used a version of its o3 model optimized for web browsing and data analysis. These systems compare information across sources, so pages with specific facts, data and clear explanations give them more to work with than thin promotional copy.
How deep research works
Planning the research
The tool starts by turning your question into a plan. Gemini shows this plan to the user before starting. Other tools may ask clarifying questions first, such as budget, location or priorities. This step resembles query fan-out, but on a larger scale.
Searching and reading
The agent runs searches, opens pages and reads them. Based on what it finds, it decides what to search next. OpenAI described its agent as able to change direction when it encounters new information. In February 2026, OpenAI added the option to restrict searches to trusted sites and to connect deep research to apps and other data sources.
Writing the report
The tool combines its findings into a structured report, usually with headings, comparisons and citations linking to the sources. OpenAI's report includes a summary of the agent's reasoning, and Perplexity's can be exported as a PDF or shared as a page.
Known limitations
Deep research can still be wrong. OpenAI said at launch that its agent can sometimes hallucinate facts or make incorrect inferences, may struggle to tell authoritative information from rumors and often fails to convey uncertainty accurately. Readers should check the cited sources for important decisions.
How to show up in deep research reports
- Make sure your pages are reachable. Deep research tools search the web, so the usual access rules apply. Allow the relevant crawlers, such as OAI-SearchBot for ChatGPT, and make sure key pages are indexed.
- Write for detailed questions. Deep research questions are long and specific. Create pages that cover costs, timelines, requirements, comparisons and who your service is best for.
- Publish evidence. Original research, case examples with real numbers and clear methodology give research agents something worth citing.
- Be specific and current. Include dates, locations, specifications and pricing ranges where you can. Keep them up to date.
- Earn coverage elsewhere. Deep research reads reviews, directories, industry publications and forums. Being described accurately in those places matters as much as your own site.
- Test it yourself. Run a deep research query that a buyer might use and see which sources appear. Gaps point to content worth creating.
Common mistakes and misconceptions
- "Deep research only uses top-ranking pages." These tools read many sources across many searches. Strong rankings help, but specific, useful pages further down can still be cited.
- "A deep research report is always accurate." Providers say the tools can make mistakes. Treat reports as a starting point and check the sources.
- "Longer content wins." Length alone doesn't help. What matters is whether a page answers the specific questions a research agent is trying to resolve.
- "It works the same on every platform." Each tool has its own search systems, models and limits. A source cited by one may not appear in another.
Deep research vs. AI search
Standard AI search, like ChatGPT search or Perplexity's default mode, answers a question in seconds. Deep research takes minutes, runs many searches and produces a long report. AI search is for quick answers. Deep research is for decisions that need comparison and evidence. Many of the same sources can show up in both, but deep research gives detailed pages more chances to be found.
How Butter approaches deep research
At Butter, we include detailed, research-style questions in the monthly AI prompt testing that's part of our GEO plan. We look at which sources AI tools use for the complex questions a client's buyers ask, and whether the client is among them.
When we find gaps, we recommend content that answers those questions directly, along with an indexing strategy so the pages can be found and outreach that earns mentions on the third-party sites research agents tend to read. We can't guarantee inclusion in any AI report, but we can make your content a stronger candidate.
Frequently asked questions
How long does deep research take?
It depends on the tool. OpenAI said ChatGPT deep research takes about 5 to 30 minutes, while Perplexity said most of its Deep Research tasks finish in under three minutes.
Which AI tools offer deep research?
ChatGPT, Google Gemini and Perplexity all offer deep research features. Google also offers Deep Search inside AI Mode, which runs many searches and builds a cited report.
Can I optimize specifically for deep research?
Not with special tricks. The best approach is detailed, accurate content that answers specific buyer questions, plus crawlable pages and accurate coverage on other trusted sites.
Are deep research reports reliable?
They are useful but not perfect. OpenAI has said its agent can hallucinate facts and struggle to separate authoritative information from rumors, so check the cited sources before acting.