How does it know which bank you mean?
Know how AI picks a word's meaning, and hand it the words that decide.
Which report?
You said “the report”. It summarised the other one.
Each word looks back
In “by the river bank”, bank looks back at each word. It weighs which matter, and settles on a meaning. That's attention.
New neighbour, new meaning
Now it's “loan from the bank”. Loan weighs most, so bank means money.
Say which, right there
In “summarise the report”, nothing says which one, so it guesses. Add the words that decide: “the Q3 sales report”.
Name the file, not “it”
“It” could mean either report. Name the one you mean: “the Q3 report”.
My pick for your own files
Gemini NotebookAlso good: 
Claude Projects
Built for answers drawn only from the files you add. It was called NotebookLM until July.
All my picks
Give it the words that decide.
Two meanings? Put the deciding words right beside the word, and name the file.
Find the guesses first
A made-up request. Nothing private.
- Paste the text into Claude, ChatGPT or Gemini.1 min
- Answer each question it asks.3 min
- Rewrite the request with the deciding words beside each one.4 min
- Ask: would a new colleague know which file?2 min
The request to paste
Before you start, read my request below. List each word you would have to guess, like which report, which client, which Q3, or what “it” means. Ask me about each one. Don't do the task yet. Request: Summarise the report for the client before Q3, then send it to the team.
Good looks likeA new colleague could follow it without asking “which one?”
In your assistant · as of Oct 2026 · Claude, ChatGPT, GeminiHand it the file itself
Name each file in your request too. Menus move often.
- CheckEach file named
- CheckDeciding words beside
- CheckNo unclear “it”
Attach only files your company allows in AI tools. Practise with made-up ones.
Claude
Attach it, or keep it in a project
Or drag it into the chat. Up to 20 files a chat.
The last + adds files to the project's knowledge, used in every chat in that project.
Free plans can make up to five projects.
ChatGPT
Attach it, or add it to a project
Attach a supported file to your conversation
Free: 3 file uploads a day.
In the sidebar. Then add your files: 5 on Free, 25 on Go and Plus, 40 on Pro, Business and Enterprise.
It can use what you add to a project to give more informed answers.
Gemini
Attach it, or add it to a notebook
Or Add from Drive (needs Keep Activity on). Up to 10 files a prompt, subject to availability.
Gemini keeps your sources in mind in that notebook's chats.
Notebooks are reaching people gradually. In the European Economic Area, you connect Gemini Notebook by hand.
Quick check · three questionsDid it stick?
1In “she took out a loan at the bank”, which word does most to settle what bank means?
The answer: B Bank weighs the words before it. Loan is the one that points to money, not a river.2Your chat has a March draft and a May draft attached. Which request leaves the least to guess?
The answer: C With two drafts in the chat, “it” and “the draft” could mean either. Naming the May draft settles the meaning.3Two reports are in the chat and you ask for “the report”. Why might you get the wrong one?
The answer: A It weighs the words around a word. If none of them says which report, it has to guess.
Where the idea comes fromSide note
Why “it” is riskySide note
The colleague testSide note
Sources, checked 19 Oct 2026Source
Product details as of Oct 2026, each checked on the vendor's own page on 19 Oct 2026. Recheck by 19 Nov 2026. The examples in the pictures are made up for this lesson.
- Vaswani and others at Google Brain and Google Research, Attention Is All You Need, 2017 (the abstract: the Transformer, "based solely on attention mechanisms"; in the paper, sections 3.2 and 3.2.3: attention as a weighted sum, and in the decoder each position attends to all positions up to and including it)
- Google Research, Transformer: A Novel Neural Network Architecture for Language Understanding, 31 Aug 2017 (each word is compared to every other word; attention scores decide how much each contributes; bank can attend to river)
- Google, Machine Learning Crash Course, LLMs: What's a large language model? (self-attention asks how much each other token affects the interpretation of this one; a token can be a word, a subword or a character; pronouns are often ambiguous; "it" typically refers to a recent noun)
- Anthropic, Glossary (the context window is the text a model can look back on; Claude's underlying model predicts the next word from the previous text; tokens can be words, subwords or characters)
- Anthropic, Prompting best practices (be clear and direct; a brilliant but new employee who lacks context; the colleague test, word for word about Claude; give each of several documents its source)
- OpenAI, Prompt engineering best practices for ChatGPT (clear, specific, enough context; avoid ambiguity)
- Google, Gemini API, Prompt design strategies (clear and specific instructions; include the information it needs instead of assuming it has it)
- Anthropic, Upload files to Claude (+ in the lower left of the chat box, then Add files or photos; drag and drop; up to 20 files per chat)
- Anthropic, How can I create and manage projects? (Projects, + New Project, then + in the project knowledge; what you upload there is used across all chats in that project; Free users up to five projects)
- Anthropic, What are projects? (project knowledge gives context for the chats in that project; Free users up to five projects; a new version of projects in beta, rolling out in stages)
- OpenAI, Uploading files and audio to ChatGPT ("Attach a supported file to your ChatGPT conversation"; Free: 3 file uploads a day; files per project by plan)
- OpenAI, Projects in ChatGPT (New project in the sidebar; files per project by plan; ChatGPT can use what you add)
- Google, Upload and analyze files in Gemini Apps, computer version (Add files, then Upload, or Add from Drive with Keep Activity on and Google Workspace connected; up to 10 files a prompt, subject to availability)
- Google, Organize your projects with notebooks in Gemini Apps, computer version (on the web: Open sidebar, New notebook under Notebooks, Add sources; Gemini remembers the context of your sources; rolling out gradually; connected by hand in the European Economic Area)
Bring this to your teamTeam workshops · Get in touchBack to level 1, Start here
Say which. Name the file.
Next lesson · 15 minWhy can the same question get two different answers?