HTML
The new lingua franca for agents.
Thariq from the Claude team broke X with The Unreasonable Effectiveness of HTML where he explained why HTML > Markdown for agents:
HTML can convey much richer information compared to Markdown. It can, of course, do simple document structure like headers and formatting, but it can also represent all sorts of other information such as:
Tabular data using tables
Design data with CSS
Illustrations with SVG
Code snippets with script tags
Interactions using HTML elements with javascript + CSS
Workflows using SVG and HTML
Spatial data using absolute positions and canvases
Images using image tags
In my opinion, there is almost no set of information that Claude can read that you cannot efficiently represent with HTML. This makes it a highly efficient way for the model to communicate in-depth information to you and for you to review it.
this came on the heels of announcing Claude Design which defaults to HTML as the format for presentations:
Claude Design is based on HTML because HTML is incredibly expressive at design, even if your end surface is not HTML. Claude can sketch out a design in HTML and then write it in your language of choice, be it React, Swift, etc.
While we’ve made a step change in communication bandwidth between humans and agents, there’s also a threat to existing stores of record for presentations, other design assets and maybe even SaaS?
Yes, it’s better
Reviewing markdown files is definitely boring and while Notion is pushing to be the default “markdown rendering engine” of the internet, it's infinitely less flexible than HTML.
I've been working on a design system with Claude Code this week and all communication happens through an HTML file it served from a python server (no I didn't make that particular choice).
It’s both the output and also the interface where it shares options and ideas, even allowing for interactivity when needed. The models are just about good enough now that the documents generated are not unpleasant and I could see applying this in many more domains (research being an obvious one).
But why not even present a legal finding to me in the style of Harvard Law Review?
The future of PPT
Nevertheless, the strategic implications are even more interesting. For a while, Canva was making a strong play at being the next PowerPoint but I think it may get squeezed in the middle.
There will come a point where we won't even care what the file format is. Right now, HTML (via Claude Design) is much more versatile for agentic development while PPT (with Claude for PowerPoint) is still the institutional default.
Ironically, while HTML is an open format and Claude Design allows you to export your creations for maximum portability, it will likely be perceived as a high switching cost option because all the functionality like design systems, templates, your Claude context has an impact on your future token spend and is actually a bigger switching cost than the file format.
So while startups and more ambitious sales teams will likely jump on Claude Design, institutional adoption will be slower. Microsoft’s goal will be to use that time until they figure out how to improve the PPT format or create a new more interactive standard.
From an AI transformation perspective, this seems like a really bizarre time. Workflows are changing too fast to be meaningfully dissolved into companies and I think it’s worth to loosen up adoption policies to allow certain teams to move faster.
My recommendation for teams would be to:
+ Distinguish between iteration media and output media. Just because your final output has to be PPT doesn't mean you cannot prototype in HTML. The same distinction between prototyping and production that has been working in code will start applying to other contexts.
+ Focus on outcomes, not outputs. I've observed more creative uses of AI in sales processes. Sometimes the best output isn't even a presentation, it can be a demo user interface or a dashboard or an interactive experience.
If anything, the fact that we are even discussing HTML (a format that humans can more easily visualize and interpret) suggests that robots aren't running away with our jobs just yet.