In-process SDK MCP servers can no longer wait forever while connecting. These are add-on tool servers that a program built on the Claude Code SDK runs inside its own process. The connection attempt is now limited by MCP_TIMEOUT, which defaults to 30000 milliseconds (30 seconds).
If the time runs out:
The connection is closed and the server is reported as failed.
An error says SDK MCP server "<name>" connection timed out after <n>ms.
The failure is logged under its own reason, mcp_sdk_connect_timeout.
Why
An SDK MCP server that never finishes connecting now shows up as a clear failure with a named server. Before, it could leave things waiting with no explanation. If a server of yours is slow to start, raising MCP_TIMEOUT gives it more time.
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeImproved screen-reader output in /mcp: a disabled server is read as "off" instead of "pending"
