I also use it to automatically retrieve page responsiveness behavior in complex web apps. It uses playwright to adjust the width and monitor entire trees for exact changes which it writes structured data that includes the complete cascade of styles relevant with screenshots to support the snapshots.

There are tools you can buy that let you do this kind of inspection manually, but they are designed for humans. So, lots of clickety-clackety and human speed results.

---

My first reaction to seeing this FP was why are people still releasing MCPs? So far I've managed to completely avoid that hype loop and went straight to building custom CLIs even before skills were a thing.

I think people are still not realizing the power and efficiency of direct access to things you want and skills to guide the AI in using the access effectively.

Maybe I'm missing something in this particular use case?

It's God's gift to them when it lets them bypass ads and dl copyrighted material. But it's Satan's curse on humanity when the Zuck does it to train his llm and dl copyrighted material.

Never tried that level of autonomy though. How long is your iteration cycle?

If I had to guess, mine was maybe 10-20 minutes over a few prompts.

‘I don’t have a girlfriend. But I do know a woman who’d be mad at me for saying that.’

‘I’m against picketing, but I don’t know how to show it.’

‘I haven’t slept for ten days, because that would be too long.’

‘I like to play blackjack. I’m not addicted to gambling. I’m addicted to sitting in a semi-circle.’

> Too many requests

You have exceeded a secondary rate limit.

Please wait a few minutes before you try again; in some cases this may take up to an hour. Signing in may provide a higher rate limit if you are not already signed in.

For more on scraping GitHub and how it may affect your rights, please review our Terms of Service.

Is this the same as what Claude in Chrome does?

I tried that for a while and since I use Firefox and Chromium, the security problem of it seeing your tabs wasn't a big deal. Fresh Chrome install, only ever used for this exact purpose. Plus you can watch it working in real (actually very slow) time so if you did point it at something risky you can take over at any point.

For actual testing of web apps though, a skill with playwright cli in headless mode is much more effective. About 1-2k context per interaction after a bit of tuning.

DevTools MCP and its new CLI are maintained by the team behind Chrome DevTools & Puppeteer and it certainly has a more comprehensive feature set. I'd expect it to be more reliable, but.. hey open source competition breeds innovation and I love that. :)

(I used to work on the DevTools team. And I still do, too)

As someone that does heavy agentic coding (using basically all the tools), this is so far from the truth. People claiming this have probably never worked in large enterprise environments where things like authentication, RBAC, rate limiting, abuse detection, centralized management/updates/ops, etc. are a huge part of the development and deployment workflow.

In these situations you can't just use skills and cli tools without a gigantic amount of retooling and increased operational and security complexity. MCP is really useful here, and allows centralized eng and ops teams to manage their services in a way that aligns with the organizations overall posture, policies, and infrastructure.

> Google is so far behind agentic cli coding. Gemini CLI is awful.

This part I totally agree. It's really hard to express how bad it is (and it's really disappointing.)

Source - I know people at Google.

Some people will push back on this. They are holding out hope that the recent improvements Anthropic has made in this regard have improved the context rot problem with MCP. Anthropic's changes improve things a little. But it is akin to putting lipstick on a pig. It helps, but not much.

The reason MCP is dying/dead is because MCP servers, once configured, bloat up context even when they are not being used. Why would anybody want that?

Use agent skills. And say goodbye to MCP. We need to move on from MCP.

It is hard to say nowadays, when things change so quickly

MCP permanently sacrifice a chunk of the context window? And a skill for you cli is free?

Couldn't have been more wrong. MCP despite its manageable downsides is leagues ahead of anything else in many ways.

The fact that SoTA models are trained to handle MCP should be hint enough to the observant.

I probably build one MCP tool per week at work.

And every project I work on gets its own MCP tool too. It's invaluable to have specialized per-project tooling instead of a bunch of heterogeneous scripts+glue+prayer.

Anything specialized goes into an MCP.

I use it extensively, many of my colleagues do. I get a ton of value out of it. Some prefer Antigravity, but I prefer Gemini CLI. I get fairly long trajectories out of it, and some of my colleagues are getting day-long trajectories out of it. It has improved massively since I started using it when it first came out.

What about all the CLI tools not baked into the model's priors?

Every time someone says "extensibility mechanism X is dead!", I think "Well, I guess that guy isn't doing anything that needs to extend the statistical average of 2010s-era Reddit"

Odd that this article from Dec 2025 has been posted to the top of HN though

This is one place where human intuition helps a ton today. If you can find the most relevant snippets and give the AI just the right context, it does a much better job.

The approach I landed on was a deterministic enforcement pipeline that sits between the agent and the MCP server, so every tool call gets checked for things like SSRF (DNS resolve + private IP blocking), credential leakage in outbound params, and path traversal, before the call hits the real server. No LLM in that path, just pattern matching and policy rules, so it adds single-digit ms overhead.

The DevTools case is interesting because the attack surface is the page content itself. A crafted page could inject tool calls via prompt injection. Having the proxy there means even if the agent gets tricked, the exfiltration attempt gets caught at the egress layer.

For example, you can get a markdown out of most OpenAI documentation by appending .md like this: https://developers.openai.com/api/docs/libraries.md

Not definitive, but still useful.

Citation needed.

> The web already went through this evolution once: we went from screen-scraping HTML to structured APIs. Now we're regressing back to scraping because agents need to interact with sites that only have human interfaces.

To me, sites that "only have human interfaces" are more likely that not be that way totally on purpose, attempting to maximize human retention/engagement and are more likely to require strict anti-bot measures like Proof-of-Work to be usable at all.

We had this 20 years ago with the Semantic Web movement, XHTML, and microformats. Sadly, it didn't pan out for various reasons, most of them non-technical. There's remnants of it today with RSS feeds, which is either unsupported or badly supported by most web sites.

Once advertising became the dominant business model on the web, it wasn't in publishers' interest to provide a machine-readable format of their content. Adtech corporations took control of the web, and here we are. Nowadays even API access is tightly controlled (see Reddit, Twitter, etc.).

So your idea will never pan out in practice. We'll have to continue to rely on hacks and scraping will continue to be a gray area. These new tools make automated scraping easier, for better or worse, but publishers will find new ways to mitigate it. And so it goes.

Besides, if these new tools are "superintelligent", surely they're able to navigate a web site. Captchas are broken and bot detection algorithms (or "AI" themselves) are unreliable. So I'd say the leverage is on the consumer side, for now.

Which is called ARIA and has been a thing forever.