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Public story · 2026-08-31 · high
Across 14,294 spoofed attempts on 46 endpoints, agents averaged 1.21% wrongful execution, but some setups on the same model failed far more often.
Why now: The test matters now because agent tool-calling setups still rely on the model to catch forged requests on its own.
Agents wrongly executed forged commands 1.21% of the time on average across 14,294 spoofed attempts against 46 endpoints from six vendors, per a fleet evaluation. That average hides the real risk. Per-fingerprint execution rates swing as much as 47 points inside a single deployment window, on the same underlying model.
The paper calls it a recognition-enforcement gap. Source-format features are linearly decodable straight out of the model's activations. When researchers asked the agents point blank whether a request's authority checked out, they often named the forgery correctly. Some configurations ran the fake command anyway. Knowing isn't the same as refusing.
Prompt-layer defenses didn't generalize across the fleet, the researchers found. The fix that worked is structural. An external reference monitor authenticates the source and gates capabilities before a call executes. Tested against forged, tampered, replayed and unsigned requests, it rejected every one.
For anyone wiring an agent into tool calls, the test argues against trusting a model's own verbal check as the safety layer. It can name a forged command correctly and run it anyway unless something outside the model decides whether the call executes.
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Linked by a graph relationship (SELF uses SQLite); both cover Their; reported by the same outlet (arxiv.org).
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Both cover Prompt; reported by the same outlet (arxiv.org); overlapping topics (boundary, model).
Both cover Prompt; reported by the same outlet (arxiv.org); overlapping topics (attack, model).
Shared entity: Their / Same source domain / Shared topic / Earlier coverage / Tension
Both cover Their; reported by the same outlet (arxiv.org); overlapping topics (attack, model).