Tool poisoning, least privilege and approvals

Learn the MCP risks: a malicious server can hide instructions in a tool description (tool poisoning), tool results can contain prompt injections, and a server with too many permissions can do damage. Defences: only install servers you trust and pin versions, give each server the least access it needs (read-only database user), keep human approval for write actions, log every tool call. Try one poisoned tool description in a test setup and see what happens.