Project-scoped MCP server tools show "disabled in your connector settings" in Claude Code / Cowork despite the connector being connected (same symptom as #42453)

Summary

A project-scoped MCP server (declared in .mcp.json, transport: stdio, running via npx mcp-remote bridging to a remote SSE-based MCP server) shows as connected with all its tools loaded, but every single tool call fails with:

"This tool has been disabled in your connector settings."

This happens in Claude Code / Cowork. I have not been able to find any UI setting that actually controls this — the server in question does not appear at all in Settings → Connectors (that page only lists personal/account-level connectors, not project-scoped ones from .mcp.json).

This looks like the same bug reported in #42453 ("Custom local MCP server tools disabled in Cowork and Claude Code, but work in Claude Chat Desktop app"), which was closed as "not planned." I'm filing this as a fresh, detailed repro in case it helps get it reopened / prioritized — it's blocking real work for me.

Environment

• Platform: Windows 11
• Product: Claude Code (Cowork / Code tab in the desktop app)
• MCP server: project-scoped, declared in .mcp.json:

``json
{
"mcpServers": {
"smartlead": {
"command": "npx",
"args": ["-y", "mcp-remote", "https://mcp.smartlead.ai/sse?user_api_key=<REDACTED>", "--transport", "sse-only"]
}
}
}
``

Steps to reproduce

1. Open a project containing the .mcp.json above.
2. Start a Claude Code / Cowork session.
3. Confirm the server shows as connected (in my case: status: connected, tool_count: 170).
4. Call any read-only tool from that server, e.g. get_campaigns, get_email_accounts, check_webhook_status.

Expected behavior

The tool call executes normally, since the server is connected and the tool is listed.

Actual behavior

Every tool call returns:

This tool has been disabled in your connector settings.

Tried 3 different read-only tools, same result every time.

Additional evidence ruling out other causes

• Not an API key / auth issue — the connection itself succeeds and the tool list loads (170 tools).
• Not a stale-session issue — reproduced identically in a brand-new session, after fully closing and reopening.
• Not a naming collision with an account-level connector — the server does not appear anywhere in Settings → Connectors (checked both "Conectado" and "No conectado" tabs), so there's nothing there to toggle.
• Other project-scoped MCP servers declared the same way (.mcp.json, stdio) work fine in the same session (e.g. an n8n server, a google-docs server) — so this isn't a blanket failure of all project-scoped servers, just this one.

Related issue

#42453 (closed as "not planned") — same exact error message, same product (Cowork/Claude Code vs. working Chat interface), similar setup (local/project MCP server). Given this is a second independent report with a clean repro, could this be reopened or re-triaged?