The AI browser,
without the new browser.
Comet is Perplexity’s browser: a separate Chromium app with an assistant built in. HailBrowser is the open-source Comet alternative for the Chrome you already use — the same idea as an extension, plus the part Comet does not have, an MCP server your coding agent can drive. Comet itself ships as a closed browser; if you searched for Comet open source, this is the MIT project that gives you the same assistant without leaving Chrome.
The difference
Same idea.
Different shape.
Both products start from a fair observation: the assistant should be where the web is, not in a chat window you paste links into. The question is whether that means a new browser or a new panel in the one you have.
Comet is a browser. Installing it means a second place where your tabs, extensions and sign-ins live, and a product decision about which browser you use every day. That is a reasonable trade for people who want the assistant and the browser from the same company.
HailBrowser is an extension. It does not ask you to move. It attaches a side panel to the browser that already has your work in it, uses the tabs you already have open, and can be removed the same way any other extension is. The code is MIT licensed, so “what does it do with my page” has a readable answer.
The second difference is who can drive it. A built-in assistant is for the person typing. HailBrowser also exposes the browser over MCP, so Claude Code, OpenCode, Cursor or Codex can use the same session while you work.
Side by side
What each one is.
Comet is a real product and a fair one to compare against. This table describes shape and licensing, not a feature-by-feature teardown we have not run.
| Question | HailBrowser | Comet |
|---|---|---|
| What you install | An extension in your current browser | A separate Chromium browser |
| Your existing profile | Used as it is | A new browser to sign into |
| Source | MIT, one public repository | Closed source |
| Account | None | A Perplexity account |
| Model choice | Anthropic, OpenAI, OpenRouter, Gemini, Groq, DeepSeek, Ollama, LM Studio or any OpenAI-compatible endpoint | Perplexity’s models |
| Coding agents | Local MCP server, 18 tools, any MCP client | Not the shape it is built for |
| Speed evidence | 26 tasks at 4.2s, harness published | Measure your own tasks |
| Removal | Disable the extension | Uninstall the browser |
Comet’s features and plan change; check Perplexity’s own site for the current state. Everything in the HailBrowser column is in this repository.
Choose honestly
When Comet is the better pick.
A comparison page that cannot name the other product’s advantages is an advert. These are the cases where we would tell a friend to try Comet first.
Comet
You want a browser and an assistant from one vendor
If you are happy to make Comet your daily browser and you want its assistant wired into search, tabs and the address bar by the company that ships both, that integration is the product. Nothing to assemble.
It is also the simpler answer if you do not want to think about model keys or MCP configs.
HailBrowser
You want your browser, your keys, your agent
You already have a Chrome full of logins and extensions. You want an agent in that, a model you chose, and the same browser available to Claude Code over MCP. You want to read the code or fork it.
Install HailBrowser“Open source” is a licence, not a vibe
The extension, the MCP hub and the benchmark harness are in Shyamnath-Sankar/project-hailbrowser under the MIT licence. You can read every line that touches a page, run the same 26-task benchmark, and publish a better number if you get one.
Is HailBrowser a Comet alternative?
For the everyday part, yes. Both put an AI assistant next to the page you are reading so you can ask for something and watch it happen. HailBrowser is an extension for the Chrome you already use, so you keep your profile, your extensions and your logins instead of moving to a second browser.
Is Comet open source?
Comet is a closed-source product from Perplexity. HailBrowser is MIT licensed: the extension, the MCP server and the benchmark harness are all in one public repository, so you can read exactly what runs in your browser.
Can I use my existing Chrome extensions and logins?
Yes. HailBrowser adds a side panel to the browser you already have. Your bookmarks, passwords, extensions, tabs and signed-in sessions stay where they are; there is no new profile and no migration.
Which is better for coding agents?
HailBrowser is built for that case. It runs a local MCP server with 18 browser tools on 127.0.0.1:12306, so Claude Code, OpenCode, Cursor, Codex, Windsurf, Gemini CLI and Claude Desktop can drive the same signed-in browser. That is the part a browser with a built-in assistant does not give you.
Do I need an account or a subscription?
No. There is no HailBrowser account and no seat price. It is MIT licensed; you bring a model key from a provider you choose, or run a local model with Ollama or LM Studio. Your keys stay in chrome.storage.local.