[BUG] Claude.ai MCP servers not loading in v2.1.72 despite valid gate, scope, and token

[BUG] Claude.ai MCP servers not loading in v2.1.72 despite valid gate, scope, and token

Environment

• Claude Code version: 2.1.72
• Platform: macOS (Darwin 25.3.0, arm64)
• Auth method: claude.ai OAuth (Max subscription)
• Terminal: Tabby (also reproduced in other terminals)

Summary

Claude.ai MCP servers configured at claude.ai/settings/connectors are not appearing in Claude Code. The feature previously worked. After systematic diagnosis, every prerequisite passes — the fetch itself is silently failing at startup.

What I expected

6 servers configured on claude.ai (DeepWiki, Context7, Excalidraw, Gmail, Google Calendar, Granola) should appear in /mcp alongside local servers.

What actually happens

Only local servers (from ~/.claude.json) appear. Zero claude.ai servers load. No error messages shown.

Diagnostic evidence

1. GrowthBook gate: PASS

"tengu_claudeai_mcp_connectors": true

Confirmed in ~/.claude.json → cachedGrowthBookFeatures.

2. OAuth token scopes: PASS

scopes: ["user:inference", "user:mcp_servers", "user:profile", "user:sessions:claude_code"]

Token freshly re-authenticated. user:mcp_servers scope is present.

3. API endpoint: PASS

Direct curl to the same endpoint Claude Code would use returns all servers successfully:

curl -s \
  -H "Authorization: Bearer $TOKEN" \
  -H "anthropic-beta: mcp-servers-2025-12-04" \
  -H "anthropic-version: 2023-06-01" \
  "https://api.anthropic.com/v1/mcp_servers?limit=1000"

Returns:

{
  "data": [
    {"display_name": "DeepWiki", "url": "https://mcp.deepwiki.com/mcp"},
    {"display_name": "Context7", "url": "https://mcp.context7.com/mcp"},
    {"display_name": "Excalidraw", "url": "https://mcp.excalidraw.com/mcp"},
    {"display_name": "Gmail", "url": "https://gmail.mcp.claude.com/mcp"},
    {"display_name": "Google Calendar", "url": "https://gcal.mcp.claude.com/mcp"},
    {"display_name": "Granola", "url": "https://mcp.granola.ai/mcp"}
  ]
}

4. Environment variables: PASS

• ENABLE_CLAUDEAI_MCP_SERVERS=true (also tested with it unset — no difference)
• No CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC
• No ANTHROPIC_BASE_URL
• No conflicting MCP env vars

5. ENABLE_CLAUDEAI_MCP_SERVERS env var: NO EFFECT

Setting it explicitly to true or unsetting it entirely makes no difference. The binary strings indicate the feature is "enabled by default (GrowthBook-gated)" so the env var should only matter for opt-out.

Likely failure point

The binary contains these log messages (extracted via strings):

[claudeai-mcp] Checking gate (cached)...
[claudeai-mcp] Disabled via env var
[claudeai-mcp] Disabled via gate
[claudeai-mcp] No access token
[claudeai-mcp] Missing user:mcp_servers scope (scopes=
[claudeai-mcp] Fetching from
[claudeai-mcp] Fetch failed
[claudeai-mcp] Fetched
[claudeai-mcp] Gate returned:

Since gate, token, and scopes all pass, the failure is at the fetch stage — [claudeai-mcp] Fetch failed. The fetch succeeds when done manually with the same token, so the issue may be:

• Missing or incorrect headers in the internal fetch (the API requires anthropic-beta: mcp-servers-2025-12-04 and anthropic-version)
• A timeout during startup
• An error in parsing the response
• A race condition where the fetch runs before the token is available from the keychain

Related issues

• #21874 — Similar symptoms but caused by GrowthBook gate evaluating to false. Different root cause here (gate is true).
• #22432 — Remote MCP servers not syncing in v2.1.29 (closed)
• #24825 — Feature flag disabled after update (open)

Steps to reproduce

1. Have MCP servers configured at claude.ai/settings/connectors
2. Be authenticated via OAuth with Max subscription
3. Confirm tengu_claudeai_mcp_connectors: true in ~/.claude.json
4. Start Claude Code v2.1.72
5. Run /mcp — no claude.ai servers appear