Working with multiple n8n instances over MCP

When the n8n_instances tool is available, the user has multi-instance mode on: one MCP connection can reach several n8n instances (e.g. prod, staging, or one per client/team).

There are two ways to say which instance a call should hit:

• Name it on the call — every n8n tool (n8n_get_workflow, n8n_list_workflows, n8n_update_partial_workflow, n8n_manage_datatable, n8n_manage_credentials, n8n_executions, n8n_test_workflow, n8n_health_check, …) takes an optional instance: "<name>". It routes that one call and changes nothing else. Prefer this.
• Set the default with switch — n8n_instances({mode:"switch", name}) sets the instance used by calls that don't name one.

The default is shared more widely than it looks. On claude.ai (and other hosted connectors) one connection serves every chat and agent using it, so a switch in one chat moves all the others too — and their next unnamed call silently lands on your instance. A wrong target is usually silent: a read returns the wrong data and a write lands in the wrong place. So name the instance.