X_MCP_CONFIRMATION_QUORUM_INVALID
Means
mcpConfirmations approvers resolved a quorum no approver set can meet
Typical cause
approvers({ args }) answered a quorum that is not a whole number of at least 1, an empty or malformed from list, or more named approvers than exist once the asking actor is excluded
Fix
mcpConfirmations({ approvers: ({ args }) => ({ quorum: 1, from: ['role:<name>'] }) }) — a whole quorum of at least 1, over selectors 'role:<name>' or 'actor:<id>' that can reach it without the asking actor