I'll get flamed and downvoted if I name the open source project I've been grinding on for over a year to address sensitive data access by autonomous agents in a way that is similar... but I've been thinking of similar things - data sovereignty.
I think the solution is is for people to own their data, with cryptographic protections and audit trails. We should have the ability to grant JiT privileges to extremely narrowly scoped pieces, as needed, scrubbed of PII prior to egress. Patients should have to cryptographically sign temporary access, which is revoked immediately after the task... the ux should be as simple as a docusign... I could go on and on...
MCP is just one of many -insecure- protocols that will be swallowed by a runtime governance protocol (like g8e) that is purpose-built for security, not to 'move fast and break stuff'.