Error / Message
MCP server connection failed
A configured MCP (Model Context Protocol) server couldn't start or connect, so its tools aren't available this session.
MCP servers are external processes Claude Code connects to for extra tools — and like any external process, they can fail to start (a missing dependency, a bad command in the config) or fail to connect (a port conflict, a crashed process).
Start by checking the server's own config entry for typos in the command or arguments, then check whether the underlying process runs correctly outside of Claude Code at all — if it doesn't start standalone, it won't start here either.
Claude Code continues working without that server's tools while it's disconnected; it's a missing capability for that session, not a blocker for everything else.
Run the MCP server's own start command directly to see its actual errorFrequently asked questions
What does "MCP server connection failed" mean in Claude Code?
A configured MCP (Model Context Protocol) server couldn't start or connect, so its tools aren't available this session.
How do I fix it?
Try: Run the MCP server's own start command directly to see its actual error
Is this something to worry about?
Claude Code continues working without that server's tools while it's disconnected; it's a missing capability for that session, not a blocker for everything else.
Is this covered in OG Flow Code Premium Toolkit?
Yes — MCP server connection failed and patterns like it are covered by the commands, and in higher tiers the specialist agents and guided skills, in OG Flow Code Premium Toolkit. Tiers start at $19.90.
Want the full command, hook, and template pack?
This is one pattern from the OG Flow Code toolkit. Choose the tier that fits your workflow, including Multi-Stack for six additional language stacks.
See pricing — from $19.90 once