Show HN: Sosumi.ai – Convert Apple Developer docs to AI-readable Markdown
sosumi.aiI got tired of Claude hallucinating Swift APIs. It does a good job at Python and TypeScript, but ask it about SwiftUI and it's basically guessing.
The problem? Apple's docs are JavaScript-rendered, so when you paste URLs into AI tools, they just see a blank page. Copy-pasting works but... c'mon.
So I built something that converts Apple Developer docs to clean markdown. Just swap developer.apple.com with sosumi.ai in any Apple docs URL and you get AI-readable content.
For example:
- Before: https://developer.apple.com/documentation/swift/double
- After: https://sosumi.ai/documentation/swift/double
The site itself is a small Hono app running on Cloudflare Workers. Apple's docs are actually available as structured data, but Apple doesn't make it obvious how to get it. So what this does is map the URLs, fetch the original JSON, and render as Markdown.
It also provides an MCP interface that includes a tool to search the Apple developer website, which is helpful.
Anyway, please give this a try and let me know what you think!
For those wondering about the name, it has a fun story behind it: https://en.wikipedia.org/wiki/Sosumi
Jim Reekes talking about this in a deleted scene from the documentary Welcome to Macintosh: https://www.youtube.com/watch?v=k4J8AF25PjA
There's also a episode on https://www.macintosh.fm about the topic that I can recommend.
Great promise; sometimes need to reference docs to build context.
I looked at the examples you posted and did a quick glance. For example
'''init?(exactly: Float80)'''
the tool converted it to
'''- [initexactly-63925](/documentation/Swift/Double/init(exactly:)-63925)'''
To achieve its goal I would be worried that it dropped the verbatim function signature. Claude still figured it out, but for more obscure stuff that could be an issue.
Thanks for pointing that out. That’s most likely a mistake in how I’m translating into Markdown. I’ll look into this.
"AI-readable Markdown" — can't we just say "Markdown"? I'm serious about this, why are we focussing on making things accessible to AI when they should just be machine-readable and accessible to human beings in the first place? No need to taint this by bringing AI into it.
> why are we focussing on making things accessible to AI
Because that’s the authors actual goal? To take a web page that looks fine to human eyes but is unintuitively not accessible to AI. That’s genuinely useful and valuable.
Sure it’s no different than converting it to markdown for human eyes. But it’s important to be clear about not just WHAT but also WHY.
C’mon now. This isn’t controversial or even bad.
Hope this make apple's Xcode team realize they should do this, especially with all the recent AI integration.
Reminds me a bit of https://www.felixcloutier.com/x86/ - turning thousands of pages of Intel PDF into more semantic documentation.
How to reliably HTML to MD for any page on the internet? I remember struggling with this in the past
How hard would it be to build an MCP that's basically a proxy for web search except it always tries to build the markdown version of the web pages instead of passing HTML?
Basically Sosumi.ai but instead of working on only for Apple docs it works for any web page (including every doc on the internet)
https://pure.md is exactly what you're looking for.
But stripping complex formats like html & pdf down to simple markdown is a hard problem. It's nearly impossible to infer what the rendered page looks like by looking at the raw html / pdf code. https://github.com/mozilla/readability helps but it often breaks down over unconventional div structures. I heard the state of the art solution is using multimodal LLM OCR to really look at the rendered page and rewrite the thing in markdown.
Which makes me wonder: how did OpenAI make their model read pdf, docx and images at all?
There are APIs such as Jina AI's reader API that do this pretty well. It doesn't produce output as clean as Sosumi for Apple docs, but it's free and does a decent job.
https://jina.ai/reader
https://github.com/vivekVells/mcp-pandoc
This is awesome and timely for me...going to give it a whirl. Thanks for building. Also, there should totally be an easter egg where clicking something somewhere plays the sound!
Great idea! I just added that. Try clicking the icon in the header.
As someone who is currently building my first iOS app, I am extremely happy to have this. This will be much nicer doing my animation documentation.
I think it's safe to assume most big players have browser rendering enabled (I hope so). imo AI is struggling with a lot of languages that are not as popular as javascript, mostly because it's more niche and you don't get a lot of good examples on the web.
In my experience, coding agents seem to do a normal fetch when provided links. Which makes sense — headless browser automation is expensive, and only really necessary for interacting with a webpage.
But with these RLHF'd AIs, being confident and helpful as they are, it took me a while to realize that they couldn't actually read the Apple developer links I was giving them. Like a kid who can't read the chalkboard, but doesn't realize they need glasses.
It's expensive for sure, but probably a drop in the water compared to the cost of renting H100. Plus, it would be a massive boost in terms of data quality/quantity for them. But maybe you are right, I'm just surprised it's not the case
An “AI” that makes text “AI”-readable. How does that make any sense?
It is for the same reasons LLM are struggling to produce something that compile in Rust? I was under the impression that most of Rust documentation was plain HTML.
I don't even bother trying to render docc catalogs into JS. It's a royal pain that breaks easily.
If GitHub could support .docc files, that would be great. Otherwise, I still use Jazzy Docs.
Once upon a time, I built a project called `swift-doc`, which eventually got Sherlocked. I think what I was most upset about was their decision to call their thing "DocC". Like, adding redundant consonants to avoid name collisions is my shtick.
Long live Jazzy.
I love your stuff!
Thanks!
Just wondering - can't AI read HTML? If so how are we training our models?
The AI only sees a bit of HTML plus a bunch of JS that, when executed, generates more HTML. If the AI does not run the JS it won’t see everything. During training they probably use a crawler that runs a headless browser behind the scenes to get everything a human would get.
They can, but the token to content ratio is far less, so they work less effectively when it's put into the inference context window.
Ai can’t read something dynamically rendered with JavaScript. At the moment.
Another awesome project that does this for Apple's docs: https://llm.codes/
Also, Apple has started shipping docs like this, too. They are a bit hidden but you can find them here:
/Applications/Xcode-beta.app/Contents/PlugIns/IDEIntelligenceChat.framework/Versions/A/Resources/AdditionalDocumentation
Very interesting. You have any before and after examples?
Curious how it handles some of the concurrency stuff. Actors, async/await etc..
Sure, here are a few more examples:
- https://developer.apple.com/documentation/swift/tasklocal
- https://sosumi.ai/documentation/swiftui/button
- https://sosumi.ai/documentation/foundation/measurement
Most of the docs about the language itself live on swift.org (e.g. https://docs.swift.org/swift-book/documentation/the-swift-pr...). I've had pretty good luck getting Claude to write modern Swift code by saying things like "Use Swift 6 structured concurrency instead of GCD". But I could totally see expanding sosumi to include swift.org content, too.
Edit: Another Swift developer life hack: for new language features, copy-pasting the Swift Evolution proposal works pretty well! https://github.com/swiftlang/swift-evolution/tree/main/propo...
Are you making use of the new markdown files Apple started shipping inside Xcode? They’re probably copyrighted though
Do you have a public repo? Would love to see how it's working.
Not yet, but I plan to open source it soon. Just gotta tidy up a little bit, you know?
Why do people always say this?
It’s ok to just start coding with a public repo. Code isn’t a secret.
I think it's because, in the world of programming, people are incredibly critical. Just try putting absolutely anything out there, and you'll get certain types of people picking it apart.
I remember an early experience in my working career, when someone was sharing their sample code with a group, to demonstrate a particular concept. And one of those present picked them up on their use of magic numbers, as if that was at all relevant in the context.
I don't blame anyone for being wary of showing their work in progress. Painters often don't like their subjects trying to take a sneek peak at their work in progress, as another example.
- Keys/tokens in the code. Yes, it’s bad practice but for a hobby/personal project it’s not the end of the world
- Not wanting to get roasted
- Open source = dealing with a lot of entitlement
And the list goes on. Putting code out into the world (publicly) often sets you up for future obligation of some kind (even if it’s just saying “no”).
None of this is a stance against open source, but I understand where people are coming from.
> "Ever notice Claude struggling to write Swift code?"
Yes, that is why I quit using Claude and swapped to ChatGPT about a year ago. I've had substantially less issues with GPT.
I remember copilot with GPT helping me export Swift to C for interop. Something I could hardly find good examples and info on in my google searches.
ChatGPT does swift and objc remarkably well including UIKit and core data. Its gotten much better for project files with gpt5-mini
Wasn’t one of the benefits of AI that we don’t need special documents for AI to understand the data?
Just saying, sites like these are also pretty great for accessibility, screen reader users in particular.
I think this one would be slightly better if it rendered that Markdown as simple HTML if accessed through a real browser, but I can imagine even this version being pretty useful.
I think it could also make the "Small web" crowd pretty happy too.
Could you share what is your motivation behind doing whole domain and web hosting ?
Personally I feel that this whole AI induced problem should even exist in the first place, but even then it is ridiculous, that you have to query some web api to solve this problem, why not just publish parsed and converted to .md set of local files and be done with it.
I agree, it'd be great if Apple provided accessible documentation in the first place. Time was, Apple published self-contained docsets that you could download and read offline.
Apple's ToS pretty explicitly forbid the kind of automation required to download everything. But even if someone did that, it'd only be a snapshot in time. And a lot can can change between OS releases.
As for the hosted web app, I wanted to provide this as a public service. I plan to open source it, so anyone can self-host instead, if they're inclined.
Yeah, pre Swift documentation was very sufficient, dense and locally explorable, since then documentation started to resemble .h copy pasta without comments.