Disabled SDK MCP servers still injected into every session's --mcp-config

Disabled SDK MCP servers still injected into every session's --mcp-config

Description

Claude.app injects SDK-type MCP servers (Claude in Chrome, Claude Preview, mcp-registry, scheduled-tasks, PDF Tools) into every Claude Code session's --mcp-config argument, even when the server is disabled in Desktop preferences. This causes hundreds of unnecessary child processes.

Steps to reproduce

1. Open Claude Desktop preferences
2. Disable "Claude in Chrome" (or any SDK-type MCP server)
3. Open a Claude Code session
4. Inspect the process command line:

ps aux | grep 'disclaimer.*--resume' | head -1 | sed 's/.*--mcp-config //' | sed 's/ --setting.*//'

Output shows the disabled server is still present:

{
  "mcpServers": {
    "Claude in Chrome": {"type": "sdk", "name": "Claude in Chrome"},
    "mcp-registry": {"type": "sdk", "name": "mcp-registry"},
    "Claude Preview": {"type": "sdk", "name": "Claude Preview"},
    "PDF Tools - Fill, Analyze, Extract, View": {"type": "sdk", "name": "PDF Tools - Fill, Analyze, Extract, View"},
    "scheduled-tasks": {"type": "sdk", "name": "scheduled-tasks"}
  }
}

Impact

Each SDK server spawns child processes per session. With 8 active sessions:

| SDK Server | Process count |
|---|---|
| Claude in Chrome | 127 |
| Claude Preview | 127 |
| mcp-registry | 127 |
| scheduled-tasks | 127 |
| PDF Tools | 15 |

That's 523 unnecessary processes from SDK servers alone, many of which were explicitly disabled by the user. Combined with user-configured MCP servers (serena, context-lens, etc.) that also spawn per-session rather than shared, a typical workstation with several active sessions can easily reach 2,000-3,000 processes.

Expected behavior

• Disabled SDK servers should not appear in --mcp-config
• Ideally, SDK servers that don't need per-session state should be shared across sessions rather than spawned per-session

Environment

• Claude.app with Claude Code 2.1.78
• macOS 15.4 (Darwin 25.3.0)
• 8 concurrent sessions in Claude Desktop