The MCP spec defines icons[].sizes as an array of strings. It was declared
as a single string, so serverInfo/tool icons serialized "sizes":"any",
which strict clients (Claude Code) reject during the initialize handshake
with: expected array, received string.

Change Icon.Sizes to []string and IconFromSVG to emit ["any"].

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>