Allow per-project MCP connector allow/blocklist that overrides cloud connectors

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When MCP connectors are enabled via the cloud registry, they reload every new session even after being disabled. There's no way to persistently control which connectors load per project.

Requested behavior:

A disabledConnectors field in .mcp.json or project settings.local.json that blocks specific cloud connectors from loading
Disabled state should persist across sessions, not reset
Per-project control — some projects need healthcare MCPs, others don't
Current workaround: None. Cloud connectors re-enable every session regardless of user preference.

Why it matters: Unwanted MCPs add startup latency, clutter the tool list, and consume context window. Users working across multiple domains (healthcare, frontend, etc.) need different toolkits per project.

Proposed Solution

Proposed solution:

Add a connectors field to .mcp.json that controls cloud connector behavior per project:

{
  "mcpServers": { ... },
  "connectors": {
    "mode": "blocklist",
    "blocked": ["bioRxiv", "Medicare Coverage", "Consensus", "ICD-10", "NPI/NPPES", "PubMed"]
  }
}

Or alternatively an allowlist mode for strict control:

{
  "connectors": {
    "mode": "allowlist",
    "allowed": ["Claude in Chrome", "Claude Preview"]
  }
}

A simpler option: a single flag to disable all cloud connectors for a project:

{
  "connectors": {
    "enabled": false
  }
}

This config would be read at session startup and override the cloud connector state. The .mcp.json already controls local MCP servers — extending it to control cloud connectors is a natural fit.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

MCP server integration

Use Case Example

I build healthcare AI tools and general web apps in different project directories. My healthcare projects need MCPs like ICD-10, PubMed, Medicare Coverage, and NPI lookup. My web app projects don't — but those 6 healthcare connectors load into every session anyway, adding startup time and cluttering the tool list.

Today I disable them manually each session. Next time I open a new window, they're all back. There's no way to say "this project only needs NotebookLM and Chrome" and have it stick.

With a per-project connector config in .mcp.json, I could set each project's toolkit once and never think about it again.

Additional Context

_No response_