BananaNL: Turn Your Go-To Style Prompt into a One-Click Button for NotebookLM Slides
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Introduction
I’m Mia Sato (Mia Sato), and I’m in charge of AI research at GDX Co., Ltd.
In this post, I’ll summarize the Chrome extension “BananaNL,” which makes it easier to operationalize design/style instructions when creating materials in NotebookLM.
The point is simple: when you try to specify style properly in NotebookLM, prompts tend to get long. And then you end up stuck in the loop of:
“Where was that prompt I used last time?” → copy-paste → small tweaks… over and over again.
BananaNL is a tool that helps you manage that “usual work” as templates so it’s easier to reuse.
What you’ll learn in this article:
What BananaNL can do and how to use it
How it fits with NotebookLM’s slide generation
Criteria to decide “use it / be cautious” in EC & digital operations
Why GDX:
At GDX, we often hear concerns like “we can generate slides, but the visual style changes every time,” or “we lose time on final formatting.”
Honestly, this is the kind of work where results are hard to see—yet the hours keep piling up. So I’ll summarize this from the perspective of whether it can run as an operation.
BananaNL Overview: what it can do and how to use it
BananaNL is an extension that manages NotebookLM styles (prompts) and applies them quickly
BananaNL is a Chrome extension that helps you efficiently manage and apply NotebookLM design styles, and works with Banana X’s prompt pattern collection to support generating infographics and slides.
BananaNL – Chrome Web Store:
https://chromewebstore.google.com
Key features include:
One-click application of templates
Preview in a side panel
Saving and recalling styles
From a practitioner’s point of view, the value is this one thing:
It reduces “pasting long style instructions every time.”
That “oh right, I do this every time…” work becomes something you can actually operationalize.
NotebookLM also lets you add “style instructions” when generating slides
NotebookLM’s official help explains that you can convert sources into presentation slides, view them in NotebookLM, or share them as a PDF.
Before generating, in addition to format/language/length, you can also enter instructions such as audience and style in the field like “Describe the slides you want to create.”
In other words, NotebookLM is designed to accept style via prompt instructions, so BananaNL’s template management fits nicely.
Banana X Prompt Pattern Collection – NotebookLM Utilization Guide:
https://furoku.github.io
Workflow image: the shortest steps to get “one template” running
Since the UI may change with updates, here’s a sequence that’s hard to get lost with:
Install BananaNL in Chrome (install the extension)
Open NotebookLM (go to the slide generation screen)
Choose a style from BananaNL’s panel/button (load a template)
Preview it, and if it fits, insert it (replace long copy-pasted instructions)
Generate in NotebookLM → share as PDF (your usual sharing flow)
Tip: Don’t start by creating lots of templates.
First, create just one that you’ll definitely reuse—like a “weekly report”—and run with it. That’s the easiest.
“NotebookLM infographics change dramatically! How to easily create pro-level diagrams with templates”:
https://library.libecity.com/articles/01KEKPAMD315ZX6M313FVARYV0?utm_source=chatgpt.com
Cautions: what to check before adopting
Permissions and data handling
According to the privacy policy, it states that it does not collect/store/share personal data on servers, and saved prompts are stored locally in the browser. It also mentions that Host Permissions are required.
→ If your company has internal rules, it’s safer to decide in advance:
What permissions are granted
Whether you will operate with a rule like “don’t put sensitive business info into prompts”
Output assumptions
NotebookLM slides are typically shared as PDF. If you plan to fine-tune later in PPT, it’s best to plan ahead for conversion and re-editing steps from the start.
From GDX’s perspective: where BananaNL can be used in work
In EC operations, a surprising amount of time goes into creating and formatting materials.
With BananaNL, the key is whether you can carve out tasks that are “almost the same every time.”
Use case 1: weekly reports (sales / inventory / ads)
Work: summarize weekly numbers and format them into executive-facing slides.
How it helps: since the structure is mostly fixed, if you define the style once, you can keep using the same “mold.” You don’t need to format from scratch every week, and you can focus more on updating the content.
Caution: it works best when KPI structure is fixed. If design requests differ by approver, over-fixing templates may still leave adjustment costs.
Use case 2: promotion & CRM sharing (diagrams / key-point summaries)
Work: share campaign designs and CRM initiatives briefly with stakeholders.
How it helps: explanations with consistent formats—funnels, timelines, etc.—fit well. Diagram style instructions become long in text, so being able to recall them as templates reduces hesitation.
Note: if each initiative requires redesigning the information structure itself, it may be faster to have humans solidify the structure first.
Use case 3: CS / operations sharing (notes / changes)
Work: share inquiry trends and operational rule changes internally.
How it helps: if you template “how to present cautions,” you can move quickly to PDF sharing. In situations with continuous small changes, keeping presentation consistent helps reduce misalignment.
Caution: if logs include personal information, you must handle them carefully. If anonymization is possible, it can work—but it’s safer to define that operational boundary on the operations side.
Start here first
You don’t need to template everything from the beginning.
The most realistic approach is to pick just one item: the document you create most frequently.
For weekly reports, simply turning your style instructions into something you can call from BananaNL makes it easy to generate the next one along the same flow.
Summary
BananaNL is an extension that lets you manage long style instructions as templates and insert them with preview, when generating materials in NotebookLM. Since NotebookLM itself accepts style instructions during slide generation, the operational fit is good.
On the other hand, you should confirm extension permissions and how you handle what information goes into prompts, together with internal rules.
Next step to try: start with one template—begin with a format you will definitely repeat, such as a weekly report.
References (Sources)
(Official) BananaNL / Chrome Web Store
(Official) Generate slide materials in NotebookLM / NotebookLM Help
(Official) Privacy Policy (BananaNL-related) / note
(Expert)
https://library.libecity.com/articles/01KEKPAMD315ZX6M313FVARYV0?utm_source=chatgpt.com
For more information about GDX Co., Ltd., please see the link below:
Company website:
https://gdx.inc/
Note: Parts of this article were created with the assistance of ChatGPT and then edited and expanded by the author. This content represents the author’s personal views and does not indicate GDX Co., Ltd.’s official views or statements. The information is for reference; please check official announcements and primary sources.
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