claude_design MCP fails: 404 from api.anthropic.com/v1/design/mcp (harness-injected, unremovable)

What happened

The built-in claude_design MCP server fails on every startup:

claude_design: https://api.anthropic.com/v1/design/mcp (HTTP) - ✘ Failed to connect
Streamable HTTP error: Error POSTing to endpoint: 404 page not found

Diagnosis

• Scope: "Dynamic config (from command line)" — harness-injected, NOT in my config.
• Verified absent from settings.json, ~/.claude.json mcpServers, frontend-design plugin (skills-only), and all launch flags (claude launched plain).
• claude mcp remove "claude_design" -s dynamic → Cannot remove MCP server from scope: dynamic. The CLI suggests this exact command in /doctor, then refuses it. Dead-end UX.
• Endpoint returns 404 → feature flag enabled for the account but the endpoint isnt live.

Impact

Persistent red "MCP server not connected" banner in /doctor and /mcp. Cosmetic but unfixable by the user.

Ask

1. Stop injecting claude_design when the endpoint is unavailable, OR
2. Allow removing/disabling dynamic-scope harness MCPs.

Env

• claude installed at ~/.local/bin/claude, macOS (Darwin 25.5.0)
• Model: Opus 4.8