[BUG] MCP Server Integration Not Working Despite Correct Configuration

Issue: MCP servers configured in ~/.claude/settings.json are not being launched by Claude
Code, resulting in no MCP tools being available.

Environment:

• Platform: WSL2 (Linux 6.6.87.1-microsoft-standard-WSL2)
• Claude Code version: Latest
• MCP Server: @supabase/mcp-server-supabase@latest (v0.5.1)

Configuration:
{
"mcpServers": {
"supabase": {
"command": "npx",
"args": ["-y", "@supabase/mcp-server-supabase@latest", "--read-only",
"--project-ref=hohhoxkaqyhgeapcfcck"],
"env": {"SUPABASE_ACCESS_TOKEN": "sbp_..."}
}
}
}

Expected: mcp__supabase_* tools should be available after restart.
Actual: No MCP tools available, no MCP server processes running.

Verification Done:

• ✅ MCP server package works when run manually
• ✅ Supabase API credentials are valid
• ✅ Configuration syntax is correct
• ✅ Full Claude Code restart performed multiple times
• ❌ No MCP server processes spawned by Claude Code

Previous Issues: Originally had WSL wrapper problem ("command": "wsl" inside WSL), but
that's been fixed to use direct npx command.

This appears to be a Claude Code MCP launcher integration issue rather than a
configuration problem.