Bastion is a macOS menu-bar app that centralizes MCP server management by running one instance per profile instead of spawning separate processes for each client. It stores credentials in Keychain, reduces resource overhead, and provides a single HTTP interface for all clients to access MCP tools while maintaining isolation between different credential profiles.
As of macOS Tahoe, manually copying login keychain files between Macs no longer works on Secure Enclave-equipped machines. The metadata and secret keys used to decrypt keychain contents are tied to the source Mac's Secure Enclave, making them inaccessible on the destination Mac even with the correct password.