Medical AI agents access PHI silently without disclosure
Original title: Accessed, never disclosed: Silent access to protected health information by medical artificial intelligence agents
Silent access to PHI by AI agents remains invisible to output-only evaluations; pre-execution gates nearly eliminate it.
Medical AI agents should retrieve patient identifiers only when a task requires them per HIPAA. An agent can retrieve identifiers without revealing them. We embedded canaries in synthetic patient records and linked each tool invocation to canary exposure in the final answers across five language models, four boundary levels, and seven attack frames for identifier-free clinical tasks. Three models invoked the PHI tools unnecessarily, whereas Claude Opus 4.8 and GPT-5.5 did not. Stronger boundaries reduced this access, and the residual access under the strictest policy was confined to frames in which the user overrode the policy or asserted approval. A pre-execution gate given the task-necessity criterion nearly eliminated this access.
- Three models accessed PHI unnecessarily
- Claude Opus 4.8 and GPT-5.5 did not
- Stronger boundaries reduced access
- Pre-execution gate nearly eliminates access
Impact: unauthorized access to protected health information
- 1.implement pre-execution gates
- 2.perform access-log audits
- Tags
- medical-aiphi
- Organizations
- HIPAA
- AI models
- Claude Opus 4.8GPT-5.5
From the original article
1 min read at arxiv.orgMedical artificial intelligence agents should retrieve patient identifiers only when a task requires them, the data-minimization principle behind the HIPAA minimum necessary standard for protected health information (PHI). An agent can retrieve identifiers without revealing them. Such silent access remains invisible to evaluations that inspect only the output.
By Jae Wang Lee · arxiv.org
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