HTML is the new Markdown: How Anthropic engineers are building with Claude Code | Thariq Shihipar

2026-05-11 · Source: Lenny's Newsletter · Field: Technology & Digital — Artificial Intelligence & Machine Learning, Software Development & Engineering · Depth: Intermediate, extended

Summary

Anthropic's Claude Code engineer, Tharik, advocates for HTML as the new standard for interacting with AI agents, replacing Markdown, due to its richer communication capabilities and enhanced readability for humans. This shift allows for the creation of more engaging and interactive artifacts, such as visual plans, mockups, and custom UIs for spec editing, which ultimately improves the quality of human-AI collaboration. The discussion highlights that as AI agents like Claude 3.5 and Opus 4.5/4.7 run for extended periods and incur significant computational costs (e.g., $500 for eight hours), users are increasingly becoming "compute allocators." This necessitates a deeper engagement with planning and specification phases, where HTML's visual richness helps users stay in the loop and make informed decisions about compute allocation. The approach also extends to building living design systems and generating dynamic status updates.

Key takeaway

For AI Product Managers and AI Engineers defining project scopes and allocating compute resources, transitioning from Markdown to HTML for AI agent interactions can significantly improve engagement and output quality. By leveraging HTML's visual and interactive capabilities, you can create more readable plans, dynamic mockups, and custom editing interfaces, ensuring you remain deeply involved in the AI's process. This approach helps optimize compute spending and leads to better-aligned, higher-quality product development.

Key insights

HTML offers a richer, more engaging communication medium for human-AI interaction than Markdown, improving collaboration and output quality.

Principles

• Plans and specifications remain critical for AI agent workflows.
• Users act as "compute allocators" when deploying AI agents.
• HTML enhances human engagement with AI-generated content.

Method

Generate AI plans, specs, and UIs in HTML to facilitate human readability and interaction, enabling dynamic editing and better decision-making for compute allocation.

In practice

• Use HTML for AI-generated project plans and mockups.
• Create custom HTML UIs for interactive spec editing.
• Develop living design systems using HTML files.

Topics

• HTML for AI Interaction
• Claude Code
• Compute Allocation
• Interactive UIs
• Living Design Systems

Best for: CTO, VP of Engineering/Data, Executive, AI Engineer, AI Product Manager, Director of AI/ML

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• Anthropic Lead: HTML Increasingly Better Than Markdown at Keeping Humans Engaged in Agentic Loops — HTML's visual and interactive capabilities enhance human engagement and productivity in complex AI agent workflows.

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Editorial summary, takeaway, and curation by AIssential. Original article published by Lenny's Newsletter.