MCP servers disabled by feature gate despite correct configuration

Problem

MCP servers are not loading despite correct configuration. The debug logs show that the claudeai-mcp gate returns false, disabling MCP functionality.

Environment

• Claude Code version: 2.1.29
• Platform: Slackware Linux 15.0 (kernel 6.6.9)

Configuration

MCP config at ~/.claude/mcp.json:

{
  "mcpServers": {
    "visual-compare": {
      "command": "node",
      "args": ["/home/user/.claude/mcp-servers/visual-compare/index.js"]
    }
  }
}

The MCP server starts correctly when run manually and uses the official @modelcontextprotocol/sdk package (v1.25.3).

Debug Log Evidence

2026-02-03T01:25:34.966Z [DEBUG] [STARTUP] Loading MCP configs...
2026-02-03T01:25:35.328Z [DEBUG] [STARTUP] MCP configs loaded in 362ms
2026-02-03T01:25:35.977Z [DEBUG] [claudeai-mcp] Checking gate (cached)...
2026-02-03T01:25:35.977Z [DEBUG] [claudeai-mcp] Gate returned: false
2026-02-03T01:25:35.977Z [DEBUG] [claudeai-mcp] Disabled via gate

Expected Behavior

MCP servers defined in the config should be started and their tools should be available in the session.

Actual Behavior

MCP configs are loaded successfully but then disabled by the claudeai-mcp feature gate. No MCP tools appear in the session. Restarting Claude Code multiple times does not resolve the issue.

Questions

1. Is MCP support being gradually rolled out?
2. Is there a way to opt-in to MCP functionality?
3. Is there a specific configuration or account setting required to enable MCP?