Feature request: ability to suppress built-in MCP servers from tool injection

Summary

Claude Code injects several built-in MCP servers into every session regardless of user preference:

• claude_ai_Canva
• claude_ai_Gmail
• claude_ai_Google_Calendar
• computer-use

These are hardcoded into the app bundle and cannot be removed through any current configuration option. The existing deniedMcpServers setting in settings.json prevents them from being called but does not remove them from the deferred tool list — they still appear in the system tools injection and consume tokens every session.

Problem

• These tools add token overhead on every single request even when the user has no intention of using them
• There is no way to opt out — they don't appear in claude.ai web integrations settings, the desktop app settings, or any config file
• Users who want lean, token-efficient sessions have no recourse

Requested Change

Add support for fully suppressing specific built-in MCP servers from being injected into the tool list entirely. This could be via deniedMcpServers in settings.json (extending its current behavior) or a new disabledMcpServers / enabledMcpServers allowlist config.

Expected Behavior

A user who adds e.g. claude_ai_Canva to a deny/disable list should see zero token cost and zero presence of that server's tools in any session.