Phase 3 · Claude · Level 3 · Power User
Claude in the browser and in Office apps
By the end, you'll be able to…
- Recognise what Claude for Chrome, Claude for Excel and Claude for PowerPoint each do
- Judge which surface fits a task, and where the human check has to stay
- Name the extra risk that comes with letting Claude act inside your browser or files
Why it matters
Claude no longer lives only in the chat window. It can ride along in your Chrome browser and work directly inside Excel and PowerPoint. You don't need to adopt all of these tomorrow, but you should know they exist, what each is good for, and, because these surfaces let Claude act on live data, where the risks change. This is an awareness lesson: enough to make a sensible call about which one is worth trying.
Claude leaves the chat window
For most of this course, using Claude meant going to a chat, bringing your material to it, and taking the answer away. That's still the workhorse. But Anthropic has been putting Claude where the work already happens, inside your browser and inside the Office apps, so you don't have to copy things back and forth. Three of these are worth knowing about. All are moving quickly, and several are in "research preview" or beta, meaning they work but are still being refined and may change or be limited to certain plans. Treat this lesson as a map, not a manual.
Claude for Chrome: an assistant that can use your browser
Claude for Chrome is a browser extension that lets Claude see the page you're on and take actions in the browser for you: clicking, filling forms, moving between tabs, working through a task across several pages. Where ordinary Claude can only talk about a web page you paste in, this can actually operate the browser. Anthropic's own examples include managing a calendar, drafting email replies, and filling in routine forms. It began as a small research preview and has been widening to paid plans, so availability depends on your plan and the date.
This is powerful and it is where the risks jump. An assistant that can act in your browser, logged in as you, can do real things, and a web page can carry a hidden prompt injection: text that tries to hijack Claude into doing something you didn't ask. Anthropic has been open that browser use raises the stakes here and has built defences, but has also published that injection attacks still succeed a meaningful fraction of the time. The practical rule: let it act only on sites you trust, watch what it's doing rather than walking away, and never let it complete anything irreversible (a purchase, a send, a permission change) without you confirming. This is a supervised co-pilot, not an autopilot.
On this open page only, read the content and give me a five-bullet summary plus any dates or deadlines mentioned. Do not click any links, submit any forms, or navigate away from this page. If the task needs an action, stop and tell me what you'd do rather than doing it.
Why this works: Naming a read-and-summarise job on a trusted internal site, with an explicit 'don't click, submit or change anything' boundary, keeps a browser-acting assistant on the safe side of the line: it gathers, you decide. The boundary is the point.
Claude for Excel: analysis inside the spreadsheet
Claude for Excel puts Claude in a sidebar inside Microsoft Excel, where it can read, analyse, modify and even build workbooks, working on the actual cells rather than a pasted copy. You can ask it to explain a model, add a column with a formula, clean a messy export, or draft a new sheet, all without leaving Excel. It's released as a beta/research preview, and much of the early investment has gone into finance work, but the everyday value is broad: it turns "wrestle with this spreadsheet" into "ask the spreadsheet".
The judgement point is the one from Level 2's data-analysis lesson, now sitting inside your file: when Claude reports a number, be sure it computed it rather than eyeballed it, and be sure you told it how to treat blanks and errors. Working in the real workbook makes the answers feel authoritative; the maths still needs the same scrutiny.
This sheet is a messy sales export. Standardise the region names to one consistent set, flag any blank or clearly wrong values rather than guessing them, and put stray text that's landed in the amount column into a separate notes column. Before changing anything, list the fixes you propose and wait for me to confirm.
Why this works: Spelling out the specific messes (inconsistent regions, blanks, stray text in number columns) and asking for the changes to be listed rather than silently applied keeps you in control of a tool that's editing your real file, and lets you verify each fix.
Claude for PowerPoint: on-brand slides from your template
Claude for PowerPoint works the same way in PowerPoint: it reads your existing template (the slide master, layouts, fonts and colours) and builds slides that follow your house style rather than generic ones. Give it the content and it drafts the deck using the right layouts and branding, which removes most of the fiddly formatting that makes slide-making slow. As with the others, it's an evolving feature, and Claude can also create slide files from within the Claude apps directly if you don't have the add-in.
Using this presentation's existing template (its layouts, fonts and colours), build a short deck from the content below: a title slide, three or four content slides, and a closing slide with next steps. Use only the figures and facts I've provided; don't invent data to fill a slide, and leave a clearly marked placeholder if something's missing. Content: [paste].
Why this works: Pointing Claude at your existing template and giving it the content lets it build slides in your real branding, which removes the slow formatting work, while asking it to keep every figure to what you supplied stops a persuasive-looking deck from smuggling in numbers you never gave it.
The trap here is the opposite of Excel's: a beautifully formatted, on-brand deck is persuasive, so a wrong figure or an overclaimed headline lands with more authority than it should. Polish is not proof. Read the substance of every slide as critically as you would a plain draft.
Which surface, and when
A quick way to choose: if the task lives on the web and needs Claude to act across pages, that's Chrome, used with a close eye. If it lives in a spreadsheet, that's Excel. If the output is slides, that's PowerPoint. If it's really a thinking, writing or analysis task where you're happy to bring the material to Claude, the ordinary chat, Project or Artifact you already know is often simpler and keeps a tighter boundary around your data. New surfaces are convenient; they aren't automatically the right tool.
Try it now
Common mistakes
- Treating the browser assistant as autopilot. Letting Claude for Chrome click and submit unwatched invites both mistakes and hijacked instructions from the pages it reads. Supervise it, and keep irreversible actions behind your confirmation.
- Assuming a research-preview feature is finished and available to everyone. These surfaces are still changing and often gated by plan. Check what you actually have before building a workflow on it.
- Skipping the boundary on live files. Letting Claude edit a spreadsheet silently means errors get baked in unseen. Ask for proposed changes first, then confirm.
- Over-trusting polish, especially in slides and spreadsheets. A branded deck and a formatted workbook look authoritative, which is exactly when a wrong figure slides through. The formatting proves nothing about the numbers. Check the substance (computed totals, real dates, honest headlines) as hard as you would in a plain-text draft, and harder before anything goes to a manager or a client.
Keeping current
These surfaces are new and evolving fast. Availability, plan requirements and safety controls will all shift. The durable points are that Claude can now act in your browser and inside Office apps, that this trades convenience for a wider risk surface, and that a human check belongs on anything that acts or that others will rely on. For current status see Claude for Chrome, the Claude for Excel help article, and the Claude release notes. Accurate as of 13 July 2026.