Validate if a given string is a valid HPO ID format and check if the term exists
AI agents call validate_hpo_id to retrieve information from Unofficial HPO MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves validation status and checks existence of ontology terms without creating, modifying, deleting, or executing external operations. It is a pure read operation on the HPO database with no side effects. The blast radius if misused (e.g., rapid validation requests) is minimal—rate-limiting or API throttling would be the only practical concern.
From the tool's definition Tool validates HPO ID format and checks term existence. Description indicates 'check if the term exists' — a lookup/query operation with no modification of data.
Attacks that exploit this kind of access
Validate if a given string is a valid HPO ID format and check if the term exists. It is categorised as a Read tool in the Unofficial HPO MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Unofficial HPO MCP Server MCP server in PolicyLayer and add a rule for validate_hpo_id: 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 Unofficial HPO MCP Server. Nothing to install.
validate_hpo_id 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 validate_hpo_id 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 validate_hpo_id. 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.
validate_hpo_id is provided by the Unofficial HPO MCP Server MCP server (openpharma-org/hpo-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.
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