AI agents call list_immunizations to retrieve information from Healow without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and lists immunization records for a specific patient. It performs no write, execute, destructive, or financial operations. The action is purely informational and has no side effects beyond returning data. Read operations on clinical data have low severity as they do not alter the patient record or trigger external actions, though they do involve sensitive PHI.
From the tool's definition Tool name 'list_immunizations' and description 'List Immunization resources for the launch patient' indicate a retrieval operation with no modification or deletion of data. The verb 'list' is a read-only operation.
Attacks that exploit this kind of access
List Immunization resources for the launch patient. It is categorised as a Read tool in the Healow MCP Server, which means it retrieves data without modifying state.
Register the Healow MCP server in PolicyLayer and add a rule for list_immunizations: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Healow. Nothing to install.
list_immunizations is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_immunizations rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for list_immunizations. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
list_immunizations is provided by the Healow MCP server (voysi-ia/healow-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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