Pattern: Every Serious MCP Defense Now Reduces to One Rule — Server Output Is Data, Never Instructions
The Hacker News·high signal
GhostSplice's mitigation list and the earlier tool-poisoning research converge on client-side controls rather than server vetting: treat tool results strictly as data, block unchecked flow from one tool's output into the next tool's arguments, and keep a human in the deny path. This matters because GhostSplice defeats per-fragment inspection by design — no single tool description or result is malicious, so scanning individual servers cannot catch it. The practical builder move is a taint rule at the harness level, not an allowlist of trusted servers.