claude.ai META mcp connector times out in Claude Code CLI while working in claude.ai web chat

Title

claude.ai META mcp connector times out in Claude Code CLI while working in claude.ai web chat

Description

The Meta (Facebook/Instagram Ads) MCP connector, added via claude.ai → Settings → Connectors, is reachable and reported as "connected" in claude.ai web chat, but consistently fails to connect from Claude Code CLI with a handshake timeout — even after full re-authorization.

Environment

• Claude Code version: 2.1.228 (native install, darwin-arm64)
• Platform: macOS (Darwin 25.5.0)
• Connector: claude.ai META mcp → https://mcp.facebook.com/ads
• This connector previously worked fine in Claude Code CLI (per user's prior experience) and stopped working without any local config changes.

Steps to reproduce

1. Have the claude.ai META mcp connector added under claude.ai → Settings → Connectors, and confirm in claude.ai web chat that it reports as connected with tools available.
2. In Claude Code CLI, run:

``
claude mcp list
``

1. Observe that every other MCP server (including other claude.ai connectors: Gmail, Google Drive, TikTok, HeyGen, Higgsfield, Runaway, Spotify, plus local stdio servers) connects successfully, but:

``
claude.ai META mcp: https://mcp.facebook.com/ads - ✘ Failed to connect — MCP server "claude.ai META mcp" connection timed out after 30000ms
``

What I already ruled out

• Network/DNS/firewall: curl -I https://mcp.facebook.com/ads and a POST with initialize JSON-RPC body both return an immediate (sub-second) 401 Unauthorized with a valid www-authenticate: Bearer ... challenge header — the endpoint itself is healthy and fast.
• Proxy/VPN interference: no *_PROXY env vars set, no active VPN interface.
• Stale local OAuth token: claude mcp logout "claude.ai META mcp" reports credentials aren't stored locally at all ("its credentials live on claude.ai, not this machine"). Ran claude mcp login "claude.ai META mcp", completed the browser authorization flow on claude.ai, restarted Claude Code — same timeout persists.
• Just slow, not hung: re-ran the health check with MCP_TIMEOUT=120000 — still times out at 120s, not just the default 30s.
• Local install issue: claude doctor reports no installation issues.

Expected behavior

The claude.ai META mcp connector should connect in Claude Code CLI the same way it does in claude.ai web chat, since claude.ai itself reports the connector as healthy and its tools as available.

Actual behavior

Claude Code CLI cannot complete the MCP handshake with https://mcp.facebook.com/ads and times out, even though:

• The connector is authorized and healthy per claude.ai web chat.
• The endpoint itself responds instantly to unauthenticated test requests.
• Every other claude.ai connector (Gmail, Drive, TikTok, HeyGen, Higgsfield, Runaway, Spotify) connects fine from the same Claude Code session.

This points to an issue specific to how Claude Code (or the claude.ai↔Claude Code connector bridge) negotiates the authenticated session with this particular connector — possibly on the Anthropic backend side rather than in the local client.