Support selective enable/disable of individual claude.ai MCP servers

Feature Request

Currently, the ENABLE_CLAUDEAI_MCP_SERVERS env var is all-or-nothing — it either enables or disables all claude.ai MCP servers in Claude Code. There's no way to selectively show/hide individual servers.

Use Case

Many users find only a subset of the claude.ai MCP servers relevant to their workflow (e.g., Slack and Sentry but not Figma or Airtable). Having 15+ servers cluttering the available tools list creates noise and confusion, especially for engineers who only need a few.

Proposed Solution

Support a per-server allowlist or denylist configuration, for example in ~/.claude/settings.json:

{
  "claudeAiMcpServers": {
    "enabled": ["Slack", "Sentry", "Sourcegraph"],
    "disabled": ["Figma", "Airtable", "Box"]
  }
}

Or alternatively, a simpler denylist approach:

{
  "disabledClaudeAiMcpServers": ["Figma", "Airtable", "Box", "Hex"]
}

Current Workaround

The only workaround is to disable all claude.ai MCPs with ENABLE_CLAUDEAI_MCP_SERVERS=false and then manually re-add desired servers via claude mcp add, which loses the managed auth benefits.

Context

This came up in internal discussion at Lyft where multiple engineers expressed wanting to keep some servers (like Slack) but hide the majority they don't use.