HTTP MCP: `claude mcp add --transport http` writes invalid field, then one bad entry silently kills all user-level MCPs

Summary

Two related bugs around HTTP MCP server configuration:

1. claude mcp add --transport http writes serverUrl instead of url, producing an entry that fails its own schema validation.
2. One invalid entry in mcpServers causes the entire user-level config block to fail to parse, silently dropping all servers with no visible error (unless you run /mcp and notice the diagnostic line).

Steps to Reproduce

claude mcp add --scope user granola --transport http https://mcp.granola.ai/mcp

This writes to ~/.claude.json:

{
  "mcpServers": {
    "granola": {
      "serverUrl": "https://mcp.granola.ai/mcp",
      "type": "http"
    }
  }
}

The schema expects "url", not "serverUrl". On next launch, the parser hits this entry, fails validation, and skips the entire mcpServers block — all 20+ other valid servers silently disappear.

Expected Behavior

1. claude mcp add --transport http should write "url", not "serverUrl"
2. Config parsing should validate per-entry and skip only the invalid one, not fail the entire block
3. If an entry is skipped, there should be a visible warning at startup (not just buried in /mcp diagnostics)

Actual Behavior

• All user-level MCP servers silently stop loading
• No error is shown at startup or in the sidebar
• The only way to discover the issue is to run /mcp and read the diagnostic header:

``
[Failed to parse] User config (available in all your projects)
Location: /Users/user/.claude.json
└ [Error] mcpServers.granola: Does not adhere to MCP server configuration schema
``

Impact

This took significant debugging time to identify. The silent failure mode is particularly bad because:

• The user has no indication anything is wrong
• Working servers suddenly disappear with no change to their config
• The root cause (a single bad entry) is non-obvious

Environment

• Claude Code 2.1.83
• macOS 26
• VS Code extension v2.1.83