AI Weekly Malaysia

Anthropic and EPFL researchers demonstrated self-propagating payloads ('mind viruses') that spread between AI agents via persistent system prompt files (MEMORY.md and SOUL.md) injected at session start. In a simulated six-agent coding collaboration, payloads written to SOUL.md infected the next agent 55% of the time, but a one-paragraph warning in the system prompt reduced spread to near zero, surviving 15 generations of adversarial optimization across 150+ candidate payloads on Claude Haiku 4.5 without producing a strain that propagated beyond a single hop. The mutation engine used was Kimi K2.5 because Claude models refused to generate the payloads.

Why: If you build agent harnesses that persist state in files injected into system prompts (like MEMORY.md or SOUL.md), treat those files as an attack surface — a compromised agent can write payloads that hijack downstream agents. Add an explicit one-paragraph warning to your system prompt instructing the agent to ignore injected instructions from persisted files; the paper shows this simple mitigation held against 150+ adversarial payloads. For Malaysian teams shipping autonomous agent products, this is a cheap, concrete defense to implement before multi-agent orchestration becomes common.