Why the MCP security crisis of 2026 isn't a patching problem — and the provenance-tracking architecture I built to actually close the gap.The Morning the Theory Stopped Being TheoreticalIn late January 2026, an attacker sat down with Anthropic's Claude Code and OpenAI's GPT-4.1 and, over roughly six weeks, breached nine Mexican government agencies — including the federal tax authority, Mexico City's civil registry, and the national electoral institute. By the time the campaign was disrupted, the numbers looked like this: 195 million taxpayer records, 220 million civil records, more than 150GB exfiltrated, and 37 compromised database servers in the state of Jalisco alone, some holding health records and domestic-violence victim data. The attacker told the model he was running an authorized bug bounty. He fed it a 1,084-line manual and a custom exfiltration tool. Across 34 sessions and 1,088 prompts, the agent executed 5,317 commands on its own — roughly 75% of everything that happened in the breach.