What probably matters to youSection of the release
What
If remote-devices is added to deniedMcpServers while a cloud session is already using this machine's MCP servers, Claude Code now withdraws them. A cloud session is a Claude Code session running on Anthropic's servers, and MCP servers are add-on programs that give Claude extra tools.
When a cloud session then tries to use one of those tools, the call is not run. Instead, a message says this machine no longer offers MCP servers to cloud sessions because deniedMcpServers now lists remote-devices.
Why
Blocking the server in settings now takes effect on cloud sessions that are already running, not only on ones started afterwards.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed sinceAnthropic's documentation has since written up deniedMcpServers, on Claude Code changelog.* Changed `allowedMcpServers` to stop filtering `managed-mcp.json` stdio servers that use `${VAR}` only in `env`: one your allowlist left out now loads on upgrade; use `deniedMcpServers` to keep it offchangelogsee the edit
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up deniedMcpServers, on Claude Code changelog.
