Parse a phone number with libphonenumber and run a live HLR (Home Location Register) lookup. Returns current carrier (post-porting), original carrier, ported flag, reachability, MCC/MNC. Pass numbers in E.164 (
AI agents call postio_phone_validate to retrieve information from Postio without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is purely informational data retrieval about phone number metadata and carrier status. While it accesses live carrier data via HLR lookup, it does not create, modify, delete, or execute operations—only reads and returns validation results. The blast radius if misused is low (information disclosure about which carriers serve numbers, reachability status) with no ability to affect systems or data.
From the tool's definition Tool performs live HLR lookup and validation, returning carrier and reachability status. No modification of data, no code execution, no deletions, no financial transactions. It queries an external carrier database and parses phone numbers.
Attacks that exploit this kind of access
Parse a phone number with libphonenumber and run a live HLR (Home Location Register) lookup. Returns current carrier (post-porting), original carrier, ported flag, reachability, MCC/MNC. Pass numbers in E.164 (. It is categorised as a Read tool in the Postio MCP Server, which means it retrieves data without modifying state.
Register the Postio MCP server in PolicyLayer and add a rule for postio_phone_validate: 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 Postio. Nothing to install.
postio_phone_validate 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 postio_phone_validate 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 postio_phone_validate. 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.
postio_phone_validate is provided by the Postio MCP server (postio-uk/postio-integrations). 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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