Claude Code 2.1.292 negotiates MCP 2026-07-28 for stdio; Sume is HTTP

The 2.1.292 change is about local servers, so it is not why a Sume connection would change. Claude Code 2.1.292 (October 6, 2026) now negotiates protocol version 2026-07-28 by default for local (stdio) MCP server connections on every install, including Bedrock, Vertex and Foundry, and MCP_PROTOCOL_NEGOTIATION=legacy opts out. Sume's hosted MCP is a remote endpoint at https://mcp.sume.com/mcp, added by URL.

Which servers it touches

Use this table to sort your own server list.

If something breaks

If a local server stops working after you upgrade, set MCP_PROTOCOL_NEGOTIATION=legacy for that run, and report it to the server's author. For Sume, the quickstart covers connecting with OAuth or an API key; when connected, call mcp_health and tools_list to confirm the session sees the tools you expect.

This post makes no claim about which protocol version Sume's server speaks; the changelog line does not cover remote servers.

An upgrade routine that covers both kinds

After every Claude Code upgrade, confirm that each configured server still connects, then call one read-only tool on each.

For Sume, the cheapest proof is mcp_health, which also tells you how the session authenticated (authenticated.auth_source is mcp_oauth for an OAuth session). It is read-only and spends nothing.

For a local stdio server you own, test once with the new default and once with MCP_PROTOCOL_NEGOTIATION=legacy. If only the legacy run works, the fault is in that server's handshake, not in Claude Code and not in Sume.

• Pin nothing based on this changelog line alone.
• Record the Claude Code version in your bug report.
• Keep write scope off while you diagnose.