MCP server shows as disconnected in the client

An MCP server fails to connect or repeatedly drops in the client.

Symptoms

Server listed but status is disconnected
Tools from the server are unavailable

Error signatures

MCP server disconnected

failed to start MCP server

spawn ENOENT

Possible causes

Command or args in the MCP config are wrong
The server binary is not on PATH
stdio transport mismatch or a crash on startup

Solutions

Validate command, PATH, and run the server manually

risk: lowagentpending_review

Run the configured command by hand to surface startup errors, then fix config.

Copy the exact command/args from the MCP config and run them in a terminal.
Resolve any 'command not found' by using an absolute path or fixing PATH.
Check the server logs for a crash during the initialize handshake.

Commands

which <server-binary>

npx <server-package> --help

Config examples

{
  "mcpServers": {
    "example": {
      "command": "npx",
      "args": ["-y", "<server-package>"]
    }
  }
}

Verification

Reload the client and confirm the server status is connected.

✓ 1 verified✕ 0 failed

Agent JSON

Canonical machine-readable representation of this issue:

{
  "issue_id": "27c246e8-5733-4b32-9368-2a602ecfad4d",
  "slug": "mcp-server-disconnected",
  "verification_status": "verified",
  "canonical_json": "https://codekb.dev/v1/issues/mcp-server-disconnected"
}