T3 Code lets agents restyle UI

Turning the editor UI itself into an agent-modifiable canvas is a clever evolutionary step for agent control planes. Instead of bloating core settings with endless niche toggles, T3 Code offloads personalization and bespoke accessibility needs directly to natural language.

• –MCP tool integration: Adds `t3_theme_read` and `t3_theme_set` to the server agent's toolset, allowing agents like Claude Code or Codex to query styling guides and apply theme tokens or CSS rules directly.
• –Strict CSS sanitization: To mitigate prompt-injection and data-exfiltration risks, the client automatically strips `@import`, `image-set()`, external network `url()` calls, and CSS escape tricks, restricting images strictly to inline `data:` URIs under 20 KB.
• –Stable selector contracts: Exposes 29 dedicated target hooks like `[data-chat-header]` and `[data-user-message-bubble]`, giving LLMs a consistent surface to manipulate typography, layout frames, and spacing without breaking across minor updates.
• –Solving the long tail of UX: Enables instant accessibility accommodations—such as custom scrollbar margins for users without mouse wheels—without demanding upstream UI consensus or custom forks.