The web browser — the most boring, settled piece of software on your computer — has quietly become the hottest battleground in AI. In the space of a year, the chat box migrated out of a tab and into the browser itself, and then it grew hands. The result is the agentic browser: software that doesn’t just answer your questions but actually does things on the web for you — books the flight, fills the form, pulls the research together across a dozen tabs.
Three names dominate the fight in mid-2026: ChatGPT Atlas from OpenAI, Perplexity Comet, and Claude from Anthropic (which took a different route to the same place). We’ve tested the category and read the security research, and this is our honest comparison — what each is genuinely good at, what they cost in GBP, and the significant catch that nobody selling these tools puts on the front page.
A snapshot as of 16 July 2026. Availability and pricing in this space change monthly; prices are billed in USD and shown as approximate GBP excluding VAT. Drawn from the vendors’ own materials plus reporting and security research from Brave, the University of Washington, OpenAI and CyberScoop.
The contenders at a glance
| ChatGPT Atlas | Perplexity Comet | Claude | |
|---|---|---|---|
| What it is | A dedicated AI browser | A dedicated AI browser | A desktop/computer-use agent, not a browser |
| Platforms | macOS (Windows in progress) | macOS, Windows, iOS, Android | Desktop app + Chrome extension |
| Agent mode | Yes (“Agent Mode”) | Yes (Comet Assistant) | Yes (Cowork / computer use) |
| Price | Agent features on the ~£16/mo Plus tier | Free; Pro add-on ~£16/mo | Bundled with Claude paid plans |
| Best at | Doing — delegation, automation | Knowing — research with sources | Controlling your whole machine, coding-grade tasks |
| Cross-platform? | No (Mac-first) | Yes — the widest reach | Via desktop + extension |
The one-line version: Comet is the free, cross-platform all-rounder built for research; Atlas is the deeper, Mac-first automation tool for heavy ChatGPT users; and Claude isn’t really a browser at all — it’s an agent that can drive your entire desktop, browser included.
ChatGPT Atlas: built for doing
OpenAI launched Atlas in October 2025 as a full browser with ChatGPT woven through it. Its headline feature is Agent Mode, which executes multi-step tasks autonomously — the kind of “go and sort this out for me” delegation that first appeared in OpenAI’s Operator. It’s the fastest-growing entrant of the three, reportedly in the low tens of millions of monthly users.
Atlas’s real edge is memory. It remembers your browsing context and carries it forward: research holiday cottages in Cornwall one afternoon, and later it already has that context when you ask for restaurant recommendations. That continuity makes it feel less like a tool you operate and more like an assistant that’s been paying attention.
The trade-offs are platform and price. As of mid-2026 Atlas is macOS-first (a Windows build is in progress), which rules out a lot of UK offices running Windows. Agent features live behind the ChatGPT Plus subscription at roughly £16/month (excl VAT), with a Pro tier around £160/month for priority access and a Business plan at about £19/user/month.
- Pros: Deepest memory and context; strong autonomous agent; tight integration with the ChatGPT ecosystem.
- Cons: Mac-only for now; agent features need a paid plan; the deeper the memory, the bigger the privacy footprint.
Perplexity Comet: built for knowing
Comet is the value pick, and it isn’t close. In March 2026 Perplexity made the full Comet browser — agent mode included — free across macOS, Windows, iOS and Android, completing the widest platform rollout of any agentic browser. If you want to try this category and don’t want to pay or switch to a Mac, this is the obvious starting point.
Where Atlas is built to do, Comet is built to know. Perplexity’s research engine is baked in, and its killer feature is provenance: every agentic answer links back to the pages that produced it. For anyone doing research where you’ll have to defend your sources — journalists, analysts, students, anyone in a regulated field — that traceability is worth a great deal. It’s the same strength we flagged in our best AI tools for research guide. Paid add-ons exist (Comet Plus at around £4/month, Perplexity Pro at about £16/month) but the core browser is genuinely free.
- Pros: Free; the widest platform support; excellent sourced research; fast for quick lookups.
- Cons: Less “deep memory” than Atlas; and — see below — it’s the browser with the most publicly documented security probing so far.
Claude: the outlier that runs your whole desktop
Anthropic took a different path. Rather than ship a browser, it built a computer-use agent. After acquiring Vercept in February 2026, it launched Claude Cowork in March — a desktop agent that can control your actual machine — alongside a Claude extension for Chrome. So Claude drives the browser and everything around it: your files, your apps, your desktop.
That makes Claude the most powerful of the three for genuinely complex, multi-app work — and, unsurprisingly, the strongest at anything coding-adjacent, which is where Anthropic’s models lead. It’s less a “browse the web for me” tool and more an “operate my computer for me” one. The flip side is that a desktop-level agent has a correspondingly larger blast radius if something goes wrong.
- Pros: Broadest reach (whole desktop, not just a tab); best for coding and complex multi-app tasks; backed by Anthropic’s leading models.
- Cons: Not a polished consumer browser; the widest permissions of the three, so the highest bar for careful use.
The catch nobody advertises: these agents can be hijacked
Here’s the part that matters more than any feature list. An agentic browser acts with your logged-in credentials — your email, your CRM, potentially your bank. And the security research on this is not reassuring.
The central problem is prompt injection: hidden instructions planted in ordinary web content that hijack the agent into doing something you never asked for. This isn’t theoretical:
- Brave’s security team demonstrated indirect prompt injection against Perplexity Comet, hiding adversarial instructions in elements invisible to the user (white text on a white background, HTML comments) that caused the agent to perform sensitive cross-site actions — including fetching one-time passcodes from email and touching banking portals.
- A University of Washington study of seven agentic browsers found that four created ways to bypass the “same-origin policy,” the basic web rule that stops one site reading another’s data.
- OpenAI itself acknowledged the problem. It shipped a “Lockdown Mode” for Atlas in February 2026 and said plainly that prompt injection for browser agents may never be fully solved. When the vendor tells you a class of attack is unfixable, believe them.
This is squarely a UK data-protection issue, not just an IT one. An agent that reads pages containing personal data and acts on your accounts is processing that data — often sending it to a US model — which raises real UK GDPR questions about lawful basis and data flows. And as our piece on the US Fable 5 and Mythos ban showed, the model behind your agent can be subject to forces well outside your control. If you’re deploying one of these at work, keep your data-residency picks in mind and treat the agent as a powerful, slightly untrustworthy new hire.
Practical safeguards while the category matures:
- Don’t let an agent loose on banking, health or payroll sessions. Log out of anything sensitive before you hand over control.
- Use the confirmation and lockdown settings. Require the agent to check in before consequential actions; turn on Atlas’s Lockdown Mode or Comet’s equivalents.
- Scope it to a task, then revoke. Treat broad, standing access as the exception, not the default.
- Keep a human in the loop for anything that spends money or sends messages.
Our recommendation
There’s no single winner — it depends on what you need.
- For most people and most UK teams, start with Perplexity Comet. It’s free, it runs everywhere, and its sourced-research model is the safest fit for professional work. The price of entry is zero, so there’s little reason not to.
- If you live inside ChatGPT and work on a Mac, Atlas is the more capable doer, with memory the others can’t match — provided you’re comfortable with the deeper data footprint that memory implies.
- If your work is complex, multi-app or code-heavy, Claude as a desktop agent is the most powerful option, so long as you respect the wider permissions it needs.
Whichever you pick, the security caveat applies to all three equally. The technology is genuinely useful and improving fast — but in mid-2026 it is not yet something to point at your bank and walk away from.
Frequently asked questions
What is an agentic browser? A web browser with a built-in AI agent that can carry out multi-step tasks for you — searching, comparing, filling forms, booking things — rather than just answering questions. Atlas and Comet are dedicated agentic browsers; Claude achieves similar ends as a desktop agent.
Which AI browser is free? Perplexity Comet. Since March 2026 the full browser, including agent mode, is free on macOS, Windows, iOS and Android. ChatGPT Atlas’s agent features require a paid ChatGPT plan (from around £16/month excl VAT).
Are AI browsers safe to use? With caution. Security researchers (Brave, the University of Washington) have demonstrated prompt-injection and same-origin bypass attacks, and OpenAI has said prompt injection for browser agents may never be fully solved. Don’t let an agent operate on banking, email or other sensitive logged-in sessions, and keep a human in the loop for consequential actions.
Atlas or Comet — which should I choose? Comet if you’re cross-platform, on Windows, want it free, or do research where sources matter. Atlas if you’re a heavy ChatGPT user on a Mac and value its deeper memory and automation.
Does Claude have a browser? Not a standalone one. Anthropic ships Claude Cowork, a desktop agent that can control your whole machine (including your browser), plus a Chrome extension — a broader approach than a dedicated browser.
Final thoughts
The AI browser wars are the clearest sign yet of where AI is heading in 2026: away from the chat box and towards agents that act. Comet has won the land-grab on price and reach, Atlas is the deeper tool for the committed, and Claude quietly does the most of all by skipping the browser and taking the whole desktop. But the honest verdict is that the category is powerful and unfinished — brilliant for research and routine drudgery, not yet trustworthy with your most sensitive accounts. Use them, enjoy the time they save, and keep your hand near the wheel.
Want help working out which AI agent fits your UK team — safely? Get in touch — we’re always happy to help.
Last updated: 16 July 2026. A fast-moving category; availability and prices change often and are billed in USD. Drawn from the vendors’ own materials plus reporting and security research from Brave, the University of Washington, OpenAI and CyberScoop. See our editorial standards.