Atlas vs. Copilot Mode: the week browsers turned into AI assistants

In 48 hours, OpenAI and Microsoft both pushed the “AI browser” idea from buzzword to shipping products. On October 21, 2025, OpenAI launched ChatGPT Atlas, a full desktop browser with ChatGPT built in. Two days later, on October 23, 2025, Microsoft expanded Copilot Mode in Edge, positioning it as an “AI browser” that can read your tabs, summarize across pages, and take actions with your permission.

Below is a deep dive into what each one actually does, where they differ, what’s risky today, and which one you might want to try first.

Also Read: ChatGPT Atlas Browser Explained: Will OpenAI’s Agentic Browser Redefine How We Surf the Web?

What shipped—quick timeline

• OpenAI Atlas (Oct 21): A standalone browser (macOS first) with a ChatGPT sidebar and an Agent Mode that can navigate, click, and complete multi-step tasks (shopping, trip planning, etc.). Windows, iOS, and Android are “coming soon.” (Reuters)
• Microsoft Copilot Mode in Edge (Oct 23): An opt-in mode inside Edge that opens each new tab with Copilot, adds Actions (form-filling, booking), and Journeys (AI groupings of your browsing history), and—if you permit—lets Copilot see and reason over your open tabs. (Windows Blog)

Same idea, different form

• Architecture: Atlas is a new browser built on Chromium; Edge is already Chromium, now with Copilot Mode layered in. So under the hood, both run the web with the same engine many sites expect.
• Where AI lives: Atlas makes ChatGPT the center of the interface (sidebar + agent). Edge keeps your normal tabs but brings Copilot into new tabs, plus a side pane when you want it.
• “Agent” features: Atlas calls it Agent Mode; Edge calls them Copilot Actions. In both cases, the assistant can perform multi-step tasks in the browser after you grant explicit permission.
• Memory vs. Journeys: Atlas can store browser memories (optional) to resurface past activity; Edge groups your history into Journeys you can pick up later (also optional).

Tech media immediately noticed how visually similar the two experiences look. Microsoft’s implementation uses a darker new-tab canvas and Windows-style controls; Atlas favors a split view with its sidebar. The timing—coming the same week—made comparisons inevitable.

Side-by-side: core differences that matter

Sources: OpenAI blog & help center; Microsoft Copilot blog, Windows blog, and support docs; The Verge.

Privacy & data controls (what the fine print actually says)

Atlas (OpenAI):

OpenAI says browser memories are optional and under your control; deleting Web History also deletes associated memories. OpenAI also states that browsing content isn’t used to train models by default—you can opt in if you want. For businesses, OpenAI notes Atlas is not yet in scope for SOC 2/ISO, lacks SIEM/eDiscovery feeds, and shouldn’t be used with regulated or production data.

Copilot Mode in Edge (Microsoft):

Microsoft positions Copilot Mode as permission-based: you must enable settings that allow Copilot to read page content, and you can turn that off anytime. Microsoft’s posts emphasize that browsing history access and Journeys are opt-in and governed by Edge/Microsoft privacy standards. Admin/enterprise privacy controls piggyback on Microsoft’s established stack.

Bottom line: Both vendors now front-load consent prompts. Atlas gives you granular memory controls; Edge leans on its existing privacy model and Windows/Graph ecosystem. If you work in a regulated environment today, Microsoft’s guardrails will feel more familiar—while OpenAI itself cautions enterprises to avoid regulated data in Atlas for now.

What’s powering them?

• Atlas: Uses ChatGPT models inside the browser UI. (OpenAI’s public model lineup currently centers on GPT-5 and related families.)
• Copilot Mode: Runs on Azure OpenAI backends. Microsoft’s documentation says Copilot Chat is transitioning to GPT-5 as the primary LLM, and Copilot commonly uses GPT-4-family/o-series models depending on the experience.

Note: Model choices can change per feature and rollout ring; expect rapid iteration.

Early reliability & security risks

• Reliability: In hands-on testing, some of Edge’s Actions worked (e.g., unsubscribing from a mailing list) while others mis-fired (claiming emails were sent or reservations booked when they weren’t). Treat “one-click” autonomy with skepticism for now.
• Security: Researchers and browser vendors warn that agentic browsing increases exposure to indirect prompt injection, where a webpage plants instructions that hijack the agent. The risk isn’t unique to Atlas—it applies to all AI browsers (Edge, Comet, etc.). Until mitigations mature, keep agents sandboxed from sensitive tasks and require confirmations for actions.

Microsoft’s new “face” for Copilot: Mico

Alongside Copilot Mode, Microsoft debuted Mico, a friendly, animated avatar meant to make Copilot feel more approachable (yes, the “new Clippy” analogies are already flying). This is largely a UX layer today, but signals how Microsoft wants to package AI for mainstream consumers across Windows, Edge, and mobile.

Mico (pronounced “MEE-koh”) appears when you use Copilot’s voice mode. It listens to you, changes colors based on your conversation, and even dances around when you’re excited about something. Think of it as your AI buddy who’s always there to help.​

And here’s the best part—if you tap on Mico repeatedly, it transforms into the old-school Clippy! Microsoft clearly has a sense of humor about their past mistakes.​

But Mico isn’t just about looks. It’s part of Microsoft’s bigger plan to make AI feel more human and less robotic. When you talk about something sad, Mico’s face changes to show empathy. It’s trying to be that helpful friend who actually understands you.​

So… which should you use right now?

Choose Atlas if you:

• Want a from-scratch AI browser where ChatGPT is the primary interface.
• Are on macOS and comfortable trying a 1.0 with frequent updates.
• Value granular AI memory controls inside the browser itself. (AP News)

Choose Copilot Mode in Edge if you:

• Already live in Windows/Edge or your company standardizes on Microsoft.
• Prefer keeping your familiar browser chrome and opting in to AI per task.
• Need enterprise-grade posture today and want to stay closer to Microsoft’s compliance universe. (Windows Blog)

Either way—best practices now:

1. Keep a “clean” browser for banking/health/HR portals.
2. Require confirmation for purchases/reservations; never store payment creds in an agent’s reach.
3. Audit your settings: turn off page visibility when you don’t need it; regularly clear history/memories.

Wait, There Are MORE AI Browsers?

Oh yes. Microsoft and OpenAI aren’t the only ones in this game. It’s like everyone suddenly realized that the old way of browsing is outdated, and they’re all scrambling to create the future.

Perplexity’s Comet Browser launched earlier this year and was initially locked behind a $200-per-month subscription (yeah, seriously). But in October, they made it free for everyone. Comet does similar things—summarizes articles, helps you draft emails, and can even complete online purchases for you.​

Google Chrome isn’t sitting this one out either. They’ve integrated their Gemini AI directly into Chrome, so you don’t even need a separate AI assistant. Just ask Chrome a question about the webpage you’re on, and it’ll explain it to you like you’re five years old.​

There are others too—Opera, Arc, and a bunch of startups are all building their own versions. Everyone wants a piece of this pie.​

The bigger picture

The “AI browser” isn’t about replacing tabs; it’s about reasoning over context—tabs, history, files, and services—and then acting. This week’s launches show two routes: rebuild the browser around AI (Atlas) or make the existing browser AI-first when you want it (Edge Copilot Mode). Expect Google to answer inside Chrome, and publishers to watch traffic shifts as more users read summaries instead of pages. The game just moved from chatbots to your default window on the web.

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