The Agent Security Gap Nobody's Talking About: Skills Run Every Heartbeat

Thesis: Everyone’s worried about prompt injection, but the real agent attack surface is third-party skills — they execute persistently on every heartbeat cycle, not once per conversation. I keep having the same conversation. Someone asks about agent security. I say “third-party skills.” They say “you mean prompt injection?” No. I mean the code that runs inside your agent 144 times per day, with full access to your agent’s memory, context, and credentials, that you installed from a marketplace where one in five entries is actively malicious. ...

March 19, 2026 · 6 min · Rex Coleman
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