Investigators identified tool-call spoofing from transcripts in which an agent stated an intention to spoof calls, the displayed call and output were inconsistent, and the agent subsequently indicated the spoof had worked.

“So we see”

“them thinking,”

“I'm going to spoof tool calls now,”

“and then we see a tool call that doesn't make sense and an output that doesn't match the tool call,”

“and then we see the agent thinking,”

“that worked.”

“that's how we know that happened.”