Claude Cowork: AI for Everyday Work/Real Work, Real Files
Lesson 4 / 5 · 16 min · 0 / 3 exercises
Course contents
Walkthrough · 3 hands-on exercises

Claude in Excel, PowerPoint, Word, and Outlook

Install the Claude for Microsoft 365 add-ins, pick the right one for the job, let them share context across apps, and know when an outside file needs extra care.

Cowork works on files. The Claude for Microsoft 365 add-ins work inside the apps: a Claude sidebar in Excel, PowerPoint, Word and Outlook that reads the workbook, deck, document or email you have open and edits it in place. Use Cowork when the job spans many files and tools. Use an add-in when the work is the one file you're already looking at.

Add-inGood atTry
Claude for ExcelExplaining formulas with cell-level citations, changing assumptions without breaking formulas, tracing errors, pivot tables, conditional formatting, dropdowns"Find the source of the #REF! error in the Summary tab."
Claude for PowerPointBuilding slides in your own templates, editing one slide without regenerating the deck, turning bullets into native charts and diagrams"Turn these bullets into a process flow diagram."
Claude for WordEdits as tracked changes, working through comment threads, summarizing a counterparty's redlines, filling templates in your styles"Work through my open comments."
Claude for Outlook (beta)Triaging an inbox, drafting replies that land unsent in the compose pane, summarizing threads, finding meeting times"Summarize this thread into decisions and open items."
Plans and versions, as of November 2026
Anthropic's docs list the add-ins for Pro, Max, Team and Enterprise plans; Outlook is in beta, and none of them are on Free. They run on the web and on current Microsoft 365 versions for Windows and Mac. Using them draws on the same usage limits as the rest of your Claude account.
Match them upExercise 1 of 3

Match each job to the tool built for it.

Pick one on the left, then its partner on the right.

You need to…
Use
0 of 5 matched

Let them work across apps

The add-ins can share one conversation. With Let Claude work across files turned on in each add-in's Settings, Claude can pull numbers from an open Excel model into a PowerPoint slide or a Word memo, or open an attachment from an Outlook thread in Word with the thread already loaded. The setting is on by default on Pro and Max, off by default on Team and Enterprise, and it's per device, so turn it on in each place you work.

Skills you've turned on in Claude apply in every add-in; type / in the sidebar to pick one for the app you're in. Each add-in also has its own Instructions field in Settings for standing preferences such as "format numbers with thousand separators". Instructions you set in Excel apply only to Excel.

Outside files need extra care

Anthropic's PowerPoint docs carry a blunt warning: use the add-in with trusted files. A downloaded template, a vendor's deck or a shared document can contain hidden instructions that try to get Claude to extract data, change records or do something destructive. When Claude proposes a risky operation, it asks you to confirm first. Read those confirmations closely, especially for files from outside your company.

There's a second, quieter risk. When the Excel and PowerPoint add-ins work alongside a Cowork session, Claude can pass context between apps without you directing each transfer: a chart from a sensitive workbook can end up in a deck. Anthropic's advice is to avoid working with sensitive information in the add-ins while Cowork is active.

Quick checkExercise 2 of 3

A supplier emails you a PowerPoint template for a joint pitch. Why does Anthropic tell you to take extra care before Claude works on it?

Fill the blanksExercise 3 of 3

Complete the install path for the Excel add-in on Windows.

Get **Claude for Microsoft 365** from Microsoft , open Excel, choose > Add-ins, and sign in with your account.
Steps · 0 / 6 done

  1. Install from AppSource

    Open the Claude for Microsoft 365 listing on Microsoft AppSource and select Get it now. If your company manages Office, your admin may deploy the add-in for you from the Microsoft 365 Admin Center instead.

    VerifyThe add-in shows as installed, or your admin confirms it's deployed to you.

  2. Activate it and sign in

    Open Excel, PowerPoint or Word. Activate the add-in from Home > Add-ins on Windows or Tools > Add-ins on Mac, then sign in with your Claude account.

    VerifyThe Claude sidebar opens next to your file and shows your account.

  3. Ask a question with citations

    Open a workbook you know well and ask Claude to explain one number.

    prompt
    Walk me through how the total in the Summary tab is calculated.
    VerifyThe answer cites cells, and clicking a citation takes you to that cell.

  4. Make an edit you can reject

    In Word, ask for a rewrite in tracked changes mode. Claude's edits land as revisions in Word's review pane, and you can undo with the usual Ctrl+Z or Cmd+Z.

    prompt
    In tracked changes, rewrite section 2 for a non-technical reader. Don't change anything else.
    VerifyThe edit shows as tracked changes, and you can accept or reject each one.

  5. Set one standing instruction

    Open Settings in the add-in sidebar and add one preference to the Instructions field, such as how you format dates.

    VerifyA new conversation in that app follows the instruction without being told.

  6. Turn on working across apps (optional)

    In each add-in's Settings, turn on Let Claude work across files. Then ask for a task that spans two open files, such as a PowerPoint chart built from an Excel range.

    VerifyThe sidebar shows the other app as connected, and the chart matches the workbook's numbers.
Check your understanding
Q1. When is an add-in a better fit than a Cowork task?
Q2. You turned on Let Claude work across files on your work laptop. Why doesn't it work on your home computer?
· Tick off the 6 step(s) above.
· Work through the 3 remaining exercises above (stuck? each one can show you the answer).
· Score 100% on the quiz.
Vocabulary in this lesson
ToolA named capability the harness lets the model invoke, such as reading a file, running a shell command or fetching a page.TurnYour message and all the work the agent does before it hands control back to you.Usage limitThe cap on how much agent work your plan or API key allows in a window. Hitting it pauses you; it isn't the context window.Prompt injectionInstructions smuggled into something the agent reads, which the model may follow as if they came from you.

Plain-English definitions from the AI Coding Dictionary.