Best Perplexity primary source: Perplexity Deep Research and Search API docs. Official docs for Search, Sonar, Agent API, and cited research workflows. Start here when building or comparing grounded AI search workflows.
Best Google deep-research source: Gemini Deep Research Agent. Official Google AI for Developers guide to long-running research agents. Use it to understand cited reports, background execution, and research-agent behavior.
Best retrieval foundation: OpenAI Retrieval guide. Official OpenAI guide to retrieval and grounded answers. Use it to understand grounding patterns that apply beyond one search provider.
Deep research depends on source discipline
AI search is useful only when it makes sources inspectable. A good research workflow separates the question, source discovery, extracted claims, synthesis, citations, and uncertainty.
Perplexity, Gemini, and OpenAI docs are the right starting points because search and research products change quickly. Use courses and posts only after checking current provider behavior.
Test with questions you can verify
Before trusting a deep research workflow, run it on topics where you know the answer or can check the sources. Look for unsupported claims, stale evidence, citation mismatch, and missing counterarguments.
A useful resource should teach verification habits, not just polished reports. The report is the output; the source trail is the product.
Recommended courses and resources
-
Perplexity Deep Research and Search API docs
API docs · Perplexity · Intermediate
You want to compare search, Sonar, Agent API, and cited research workflows from the primary source.
-
Gemini Agents Overview
Guide · Google AI for Developers · Intermediate
You want the official overview of Gemini managed agents, sandbox behavior, and when to use agent workflows instead of plain model calls.
-
Perplexity Sonar models
Model docs · Perplexity · Intermediate
You need to compare Sonar, Sonar Pro, Sonar Reasoning Pro, and Sonar Deep Research for grounded search workflows.
-
Perplexity Sonar Deep Research
Model docs · Perplexity · Intermediate
You want the specific Sonar Deep Research tradeoffs, pricing, and workflow fit before using it for exhaustive cited research tasks.
-
Gemini Deep Research Agent
Guide · Google AI for Developers · Intermediate to advanced
You want the latest official Google docs for long-running research agents, cited reports, background execution, and MCP-aware investigation workflows.