Claude Code MCP server fails to start/connect: causes and fixes

Is there an outage right now?

Claude Code official status is operational. If this error persists, it is likely an implementation or environment issue on your side.

View Claude Code status →

What this error means

A configured MCP (Model Context Protocol) server failed to start or connect (e.g. "MCP server '…' failed to connect"). This is usually a config issue on the MCP server side—command, args, runtime, or env—not Claude Code itself.

Common causes

•Wrong command path or args in .mcp.json / config
•Required runtime (node / python / uvx) not installed or off PATH
•Missing required env vars (API keys, etc.)
•MCP server process fails to start or crashes
•Wrong stdio / SSE type or URL
•Insufficient execute permissions

How to fix

1.Check `claude mcp list` and connection state with `/mcp`
2.Review the command, args, and env in your config
3.Install the required runtime and add it to PATH
4.Run the command standalone to see if it starts
5.Set the required env vars (API keys, etc.)
6.Inspect logs to identify the server-side error
7.Fix the config and restart Claude Code

When waiting helps (and when it won't)

MCP issues are mostly config/environment—waiting will not help. Check config and runtime. It is independent of Anthropic outages, so MCP can fail even when the core service is fine.

Alternatives when Claude Code is down

Codex Cursor GitHub CopilotClineWindsurfContinue

FAQ

What is MCP server failed?

How do I fix MCP server failed?

Check `claude mcp list` and connection state with `/mcp` / Review the command, args, and env in your config / Install the required runtime and add it to PATH / Run the command standalone to see if it starts / Set the required env vars (API keys, etc.) / Inspect logs to identify the server-side error / Fix the config and restart Claude Code

Compare Claude Code with others

← Claude Code Open official status ↗