Check if a phone number is on the Do Not Originate (DNO) list. DNO numbers should never appear as a caller ID because they belong to entities that only receive calls (e.g., IRS, major banks). A match indicates potential caller ID spoofing. Supports prefix matching (3, 6, 7, or 10 digit patterns).
AI agents call dno_check to retrieve information from Telique MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries regulatory/compliance data (DNO list status for phone numbers) to detect anomalies, with no side effects, data modification, or execution of external operations. It is a lookup utility for security/fraud detection purposes. While the information could be sensitive, the tool itself performs only read operations against a reference database.
From the tool's definition Tool performs a 'Check' operation against a Do Not Originate (DNO) list, with no modification capabilities. Description states it 'should never appear as a caller ID' and 'A match indicates potential caller ID spoofing' — purely informational/query operations.
Attacks that exploit this kind of access
Check if a phone number is on the Do Not Originate (DNO) list. DNO numbers should never appear as a caller ID because they belong to entities that only receive calls (e.g., IRS, major banks). A match indicates potential caller ID spoofing. Supports prefix matching (3, 6, 7, or 10 digit patterns). It is categorised as a Read tool in the Telique MCP MCP Server, which means it retrieves data without modifying state.
Register the Telique MCP server in PolicyLayer and add a rule for dno_check: 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 Telique MCP. Nothing to install.
dno_check 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 dno_check 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 dno_check. 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.
dno_check is provided by the Telique MCP server (ringer/telique-mcp). 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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