The Solr MCP server is single-tenant. It does not support multi-tenancy.
The intended deployment is one instance per user, configured with that user's own Solr credentials. Every action the configured Solr identity is allowed to perform — including admin, schema, and collection operations — is by design reachable through the MCP tools. The server performs no per-user authorization or tenant isolation of its own; to limit what the tools can do, scope the Solr identity in Solr (Basic Auth, roles, mTLS, network policy).
In HTTP mode, OAuth2 authenticates that a caller is allowed in, but every authenticated caller shares the same single Solr identity — it is an access gate, not a tenant boundary.
Sharing one instance across multiple users, or otherwise treating it as multi-tenant, is unsupported: you are on your own for isolation and any resulting exposure. Multi-tenancy may be considered in a future release.