The biggest issues are usually that a third-party MCP server you're trying to use either has misconfigured CORS so the browser can't hit it, has a bespoke OAuth setup which doesn't work with @modelcontextprotocol/client, or they don't support Dynamic Client Registration (DCR) so you can't just point at it and use it. It's nice when none of these apply and it Just Works, the user can auth easily with the third-party and refresh tokens automatically handled in the background by the client.

That's the advantage, really - you didn't have to define the tools yourself, auth is handled for you, and the agent doesn't need to (and can't) access credentials or tokens as it knows nothing about MCP.

Comments URL: https://news.ycombinator.com/item?id=49309540

Points: 2

# Comments: 1

Twitch did that a while back and uBlock Origin was ineffective against their video ads within a few months.

[1] https://bsky.app/profile/soitis.dev/post/3lvk7przgus2u

https://soitis.dev/comments-owl-for-hacker-news

TL;DR: open app, use the app, install the app, have you opened the app yet?

Comments URL: https://news.ycombinator.com/item?id=48814601

Points: 3

# Comments: 2

Claude Opus on its own with filesystem tools built around the FileSystemDirectoryHandle API [3] makes for a pretty decent coding agent - I've been using the app to write itself live on its own development server ever since it got the ability to edit its own files, which is some of the most fun development I've done recently. I think writing your own harness is probably the most fun thing you can do with an LLM, which is why so many people do it - getting the model to add and then start using a new tool you had an idea for in the same chat is always fun.

[1] which seems like the best scenario for it in terms of the security/privacy issues it poses

[2] I ended up creating an MCP server rooted to a specific local directory - which I can expose to them via Cloudflare Tunnel - and a browser extension which adds a folder picker button to their chat interfaces, so I can get an almost-equivalent experience. This is really ugly in ChatGPT but works as well as I'm used to in Claude.

[3] as a bonus, the tools you write against this API will also be compatible with the Origin private file system (OPFS) API if you want to give your chats a virtual filesystem for the model to write to, or to copy user-attached files into

Provide a meta-tool which handles piping data in and out of any other tool, and make specific tools which can read/write data sources directly, bypassing context. Or you could go full code mode, but I'm not sure it's worth the lift unless you have Cloudflare numbers of APIs which would need tools.

I work on an internal model/vendor-independent chat app where the agent runs in the browser - every chat gets its own virtual origin private filesystem (OPFS) [1] directory where user attachments get written to and tools can read from/write to, and users can also provide read/write access to a real directory with window.showDirectoryPicker() [2] (both use the same API, so tools can route to/from either).

It can push and pull MBs of data through tools, e.g. pulling huge spreadsheets directly from SharePoint in 50,000 row chunks using a tool which calls the Excel Services REST API, passing those all into a code execution tool to join them together and process them, which generates an Excel output file using SheetJS, none of which goes into context.

People used to drag their multi-MB documents in and complain either it didn't work or the agent couldn't do anything useful with it. Now it just works.

[1] https://developer.mozilla.org/en-US/docs/Web/API/File_System...

[2] https://developer.mozilla.org/en-US/docs/Web/API/Window/show...

I'm currently doing something like this in the internal model-independent LLM chat app I work on at a F100, specifically targeted at our everyday users. lets the user give the model read and write access to a local folder (and OPFS lets us reuse the same fs tools we give the model for files manually attached to the chat, or for files tools want to create if they haven't granted folder access).

Every time we used to release a new version it was "still can't handle the 6MB Excel file I drop into it" when that was being extracted to CSV and added to context - now it can poke about in the big Excel file directly with SheetJS to pull the sheets/headers and inspect the shape of the data, and use locally sandboxed code execution to write code against either extracted data or the spreadsheet itself via SheetJS for pivot tables and such (all locally - none of which need go into the context).

The base models are good enough at tool calling (I really mean Claude, though, the GPTs just go on a tear calling tools with no context for the user) they're already decent at automating stuff for the user without a dedicated harness (our default system prompt is still "You are a helpful AI assistant", lol). Add tools for Graph API stuff, and now it can pull the nightly batch file from a support inbox, unzip the spreadsheet within, diff it against yesterday's and generate an import file for new users and draft an email to welcome them, something that used to be a daily support task (which I'd already automated most of - but now you don't need a dev for this kind of thing). Or go find the big 450,000+ row spreadsheet that's being automated somewhere on SharePoint, pull it down in 150,000 row chunks (Graph Excel REST API limit) and write code to go figure out whatever the user is asking.

Having implemented and used it, I like this setup so much it kinda ruined Claude.ai and ChatGPT.com for me, so I've hooked up similar access for them using a browser extension to add the folder picker input, with the extension talking to a local server to tell it which folder to give access to, and Claude/ChatGPT talking to the same server over MCP via a CloudFlare Tunnel to work with the selected folder.

After using them to implement a dark mode (and a pure black variant for OLED), plugging everything into my existing HN browser extension which already lets you apply custom CSS, and making it handle theme switching via attributes on , custom styles and theming are now manageable using it. There are a few examples in the friendly release notes above, with screenshots and copy-pasteable CSS.

If you just want to grab the stylesheet which sets up the CSS variables and application rules to use in your own thing, it's here [1], but not _everything_ is themeable without a bit more work - in particular, I had to replace the HN logo with an inline version of the SVG, so its fills can be controlled by CSS.

[1] https://github.com/insin/comments-owl-for-hacker-news/blob/m...

Comments URL: https://news.ycombinator.com/item?id=47836108

Points: 8

# Comments: 1

Plug: I added a bunch of features to Control Panel for YouTube [1] which let you either hide Shorts completely, everywhere (which is the default) or take more control of how you use them if you do (e.g. redirecting to the normal video player)

[1] https://soitis.dev/control-panel-for-youtube