Claude Code MCP connector lists no tools: Sume handshake versions

Claude Code 2.1.286 fixed MCP connectors that listed no tools for up to a day after their server dropped the older MCP handshake. Sume's hosted server has not dropped older versions in the code read here: it answers 2025-03-26, 2025-06-18 and 2025-11-25, so an empty tool list from Sume is more likely a scope or connection problem than a handshake one.

Vendor text is from the Claude Code changelog read 2026-10-01. Sume facts come from the MCP server source and the MCP quickstart. I did not test a live handshake.

Which versions does the Sume server negotiate?

The server defines 2025-11-25 as its default protocol version and a supported list of 2025-03-26, 2025-06-18 and 2025-11-25. If the client requests a version in the list, initialize echoes it; otherwise it answers with the default. The server reports itself as sume-remote-mcp with title Sume. The changelog also mentions a 2026-07-28 negotiation in other entries; that version is not in Sume's list, so a client asking for it will be answered with 2025-11-25. For the 400 case, see unsupported protocol version.

Why would the tool list still be empty or stale?

Because the server sets listChanged: false, it does not signal a changed list, so a client that cached tools has to re-fetch. Also check scope: default hosted OAuth is read-only, mutating and paid tools stay hidden until mcp:write or an API key, and write calls return insufficient_scope. A mcp:read session still lists read tools such as jobs_list and catalog_list. See list_changed and reconnect.

How do I check after a reconnect?

Reconnect from the /mcp view, then ask Claude to call tools_list or mcp_health, which the quickstart names as the first read-only checks. If the list is short, compare it with the credential you used. If it is empty, re-run claude mcp login sume and confirm the URL is exactly https://mcp.sume.com/mcp. Update Claude Code to 2.1.286 or later if you saw the stale-list symptom the changelog describes.