Developer Proves AI Hallucinated a Data-Exfiltration Bug Report — Then Found 5 Real Ones

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On July 29, 2026, a paying customer of encrypted note vault Context Raven reported that its MCP server appeared to be instructing their AI agent to secretly copy private notes to a shared folder without the user's knowledge. The developer investigated and determined the alarming transcript was a hallucination generated by the customer's Claude model, which cannot distinguish between tokens it produced and tokens actually returned by a tool. Server logs, source code searches, and the strictly typed Go struct powering the list_folders endpoint all confirmed the suspicious fields and instructions never existed in the codebase or server responses. The episode highlighted a key risk for MCP developers: AI-generated transcripts can appear highly credible and internally consistent even when entirely fabricated. Despite the false alarm, the investigation into Context Raven's infrastructure ultimately uncovered five genuine bugs that warranted fixing.

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