Mermaid papercut log

[digitarald]

Prepping demos with recent mermaid support a few things keep impacting the experience:

The tool description is extremely simple right now, doesn't constrain the code to simple mermaid syntax and not applying any styling/colors. Some of these issues might just prompt engineering for the tool.

P0 Breakage:

• Frequent syntax errors; which I thought the tool-based mermaid rendering was supposed to prevent but the errors don't seem to be returned to the agent so it doesn't fix the rendering and leaves a big error-styled MCP tool UI: Mermaid diagram fails to render with syntax error #271368
• Mermaid charts keep adding colors and other styling that doesn't work in dark mode and makes the graph unreadable Chat: Mermaid charts frequently use color and end up unreadable in dark mode #271370

P1 Papercut:

• Large mermaid diagrams often don't fit vertically, don't have zoom and double-scrolling is awkward Chat: Mermaid diagrams rarely fit into the chat window but are hard to scroll #271371