If you use Gemini Notebook seriously, you have probably noticed something: you keep typing the same instructions. "Appraise this study using risk-of-bias domains." "Always cite which source each claim came from." "Explain it in plain language, but do not soften the numbers." You write that paragraph, you get a good answer — and then the next question arrives and the model quietly drifts back to its default behaviour.

That is the gap Skills fills. A Skill is a reusable set of workflow instructions that you save once and apply to a notebook. From that moment, it is part of what Gemini Notebook reads before it answers — not just for one message, but for every question you ask in that notebook.

🧩 The one-line version: A prompt shapes one answer. A Skill shapes every answer in the notebook it is applied to.

Why a Skill is not just a longer prompt

Notebook OS already ships a Prompt Library, and the two solve genuinely different problems. It is worth being precise about the difference, because it explains why Skills work at all:

  • A prompt is a message. It goes into the chat box, shapes the reply it is attached to, and then its influence fades as the conversation moves on.
  • A Skill is a source. Applying one adds it to the notebook as a text source, alongside your papers and chapters — and Gemini Notebook grounds every answer in its sources. That is exactly why the instruction keeps holding: you did not ask nicely once, you changed the material the model is reading.

The practical consequence is the useful part. Close the tab, come back tomorrow, ask a follow-up three turns deep, generate an Audio Overview or a Report from that notebook — the Skill is still in effect, because it never left.

The built-in library

Notebook OS ships 15 built-in Skills, each written as a full working procedure rather than a one-line hint. They are grouped into five categories:

  • Research (7) — Critical Appraisal Walkthrough, Multi-Source Synthesis Digest, Evidence Extraction Table, Data Analysis Runner, Explain This Paper Simply, Guideline in Plain Language, Academic Literature Review Writer.
  • Clinical (3) — EBM Question (PICO) Consult, Guideline Comparator, Patient Case Write-Up.
  • Teaching (2) — Lecture Deck Prep Checklist, Exam Study Coach.
  • Writing (2) — Medical Translation QA Pass, Write From Sources.
  • Other (1) — Knowledge Base Curator.

Each one opens in a read-only detail view before you commit to it, so you can read the entire procedure the model will follow. Every Skill also states its prerequisite in one line — what needs to already be in the notebook for it to work well. Medical Translation QA Pass, for instance, needs both the source text and the translation loaded; it cannot check a translation it can only see one side of. Reading that line first saves you a disappointing answer.

Applying a Skill takes three clicks

1Open a notebook and find the Skills card in the Studio panel.

2Browse or search the library, click a Skill to read what it actually does, then press Apply.

3Reload the notebook. The Skill is now a source, and every answer from here on follows it.

💡 Applied Skills are tracked per notebook. The library shows an applied badge on the ones already active in the notebook you have open. If an update ships with a newer version of that Skill, the badge tells you an update is available — and Remove clears the mark when a workflow has served its purpose.

Writing your own

The built-ins are a starting library, not a ceiling. New skill opens an editor where you give it a name, a one-line description, a category, an optional prerequisite line, and the body — the actual instructions. Anything you would explain to a capable new colleague belongs in that body: the steps, the output format, the things to refuse to guess at.

If you would rather describe the workflow than write it, the editor can draft one for you: type what you want the Skill to do, and Notebook OS asks Gemini Notebook to write a structured, source-agnostic workflow you can then edit. It is a first draft, and it is meant to be edited.

On the free tier you can keep up to 3 custom Skills — enough to encode the workflows you actually repeat. Pro removes the cap and adds Modify, which lets you edit any built-in Skill in place: keep the structure of Critical Appraisal Walkthrough, but bend it toward the appraisal framework your department actually uses.

What this is good for

Skills pay off wherever the same reasoning has to be applied repeatedly and consistently:

  • Consistency across sessions. Appraise twelve papers over three weeks and every appraisal follows the same structure — which is what makes them comparable.
  • Handing over a method. Share the notebook and the person on the other end inherits the workflow, not just the files.
  • Fewer instructions per question. Once the standing rules live in the notebook, your actual questions get short again.

And nothing here is medicine-specific by nature. The built-in library leans clinical because that is where our earliest users work, but the mechanism is general: any repeated way of reading, comparing, or writing from documents can be a Skill.

The takeaway

The Prompt Library made good instructions reusable. Skills make them persistent. Write down how you work once, apply it to the notebook, and stop re-explaining yourself to a model that was always willing to listen — it just needed the instructions to still be there when you came back.