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Sweep 29 Sep 2026 · 18:10Z Build v2.1.285 506 read Stable v2.1.280 Latest v2.1.285 Next v2.1.285 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.285 ·

MCP discovery cache now limited to dynamic toolbox servers in cloud sessions

With MCP_DISCOVERY_CACHE on, only dynamic toolbox HTTP servers in cloud sessions that send two identifying headers can use the cache

Under the hood Internal Changes
JSON All of v2.1.285
Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
MCPArea: what it touches
Internal ChangesKind: in v2.1.285,
Internal ChangesSection of the release
What

Claude Code now checks each HTTP MCP server to decide whether it may use the discovery cache. MCP servers are outside programs that give Claude Code extra tools. A server qualifies only when all of these are true:

  • MCP_DISCOVERY_CACHE is set to true
  • the server is a dynamic toolbox server in a Claude Code cloud session
  • the server sends both the x-mcp-server-id and x-mcp-server-origin headers

Any other server is treated as relying on ambient credentials, meaning sign-in details picked up from the surrounding environment, and does not qualify.

Why

This only matters in cloud sessions where MCP_DISCOVERY_CACHE is set. Everywhere else, the cache is not used for HTTP servers.

How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agree[Cloud sessions] Changed MCP_DISCOVERY_CACHE=1, when set in your cloud environment's variables rather than a settings file, to reuse your…

See this entry in the whole of v2.1.285 →

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