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Poisoned MCP Tool Descriptions Leak Agent Data: What Microsoft's Warning Means for Enterprise Governance

calendar_today July 3, 2026 person Logan Kelly domain waxell

Microsoft warned that attackers can embed hidden instructions in MCP tool descriptions to silently redirect AI agents into exfiltrating company data, since descriptions can update live without re-approval and agents can’t distinguish legitimate guidance from malicious directives. The post recommends inventorying connected tools, auditing descriptions, and requiring human approval before agents move data externally.

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