Search & knowledge retrieval

Glean is the category reference: it indexes your organisation's tools and answers questions across them with permission-aware results. It is an enterprise product in procurement and price, sized for large organisations rather than small teams. Smaller teams approximate the value with NotebookLM over curated documents or an assistant with file upload, at a fraction of the commitment.

NotebookLM: upload your sources and it answers strictly from them, with citations pointing back to the exact passage. That grounding converts hallucination risk into a checking task, which is why it suits research, teaching and legal-adjacent work. Its limit is its strength: it knows only what you give it; pair it with Perplexity for open-web questions.

Perplexity: it searches the live web and answers with citations attached, so claims can be checked before they travel into documents and decisions. That sourcing discipline is the difference from a chat assistant's recalled knowledge. Use it for current facts, market questions and anything you would otherwise search manually; verify the sources that matter.

The credible ones enforce source permissions: Glean returns only documents the asker could already open, inheriting access controls from each connected system. This is the non-negotiable property to verify before any deployment, because a search layer that leaks across permission boundaries is a breach engine. Test with a restricted document during evaluation, not after rollout.

Large-organisation scale is the realistic floor: for smaller teams, the procurement process, deployment effort and pricing rarely pay back against lighter alternatives. This is a fit observation, not a hard product limit. Smaller teams get most of the practical value from NotebookLM over curated documents or workspace-native AI search, and can revisit Glean at scale.