Feature Request: MCP Scoping by Tool (Claude Code vs Cowork)

Refiled from #23996, which was auto-closed for inactivity and locked without any team engagement.

Current behavior

MCPs configured in Claude environment are accessible to both Claude Code and Cowork with no scoping mechanism.

Problem

This creates operational and security friction:

1. Context waste: MCPs intended only for Cowork (e.g., Slack) consume tokens in Claude Code's context budget even when not needed. With MCP Tool Search now active, this exacerbates the issue—Claude Code may dynamically search for and load MCPs I never intended it to use.

1. Unwanted autonomous behavior: When I mention a human by name in the context of Linear or GitHub issues in Claude Code, there's no guarantee Claude Code won't search Slack to "learn more about them." I now have to set explicit negative instructions to prevent this, adding behavioral overhead.

1. Mining risk: Claude Code can autonomously mine Slack channels if it decides those tools are relevant to a task. This violates principle of least privilege—Code should not have implicit access to company communication channels.

1. No opt-in control per tool: I want Cowork to have full Slack access for knowledge work, but Claude Code in terminal mode should have zero access. Currently impossible without manual MCP management or separate machine profiles.

Requested solution

Allow MCPs to be tagged/scoped as:

• cowork-only (accessible to Cowork research preview, not Claude Code)
• code-only (accessible to Claude Code, not Cowork)
• shared (both, default for backward compatibility)

Alternatively: UI-level scoping in Claude Desktop where I can toggle which MCPs are visible to which tool.

Why this matters

Cowork + MCP is a powerful, legitimate pattern for knowledge work. But that doesn't mean every MCP should follow Code everywhere. In team environments with security-sensitive integrations (Slack, HRIS, financial tools), this scoping is essential for operational security and preventing unintended data access patterns.

This is especially critical as MCP Tool Search gets smarter about lazy-loading—the more dynamic the loading, the more important explicit scoping becomes.