Look up denial codes (CARC/RARC) with resolution steps
AI agents call lookup_denial to retrieve information from Medical Billing 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 medical billing denial information (CARC/RARC codes and resolution steps) without modifying data or triggering side effects. It is a straightforward read operation similar to other lookup tools on the same server (lookup_bundling, lookup_cpt, lookup_icd10, lookup_modifier, lookup_payer).
From the tool's definition Tool name is 'lookup_denial' and description states 'Look up denial codes (CARC/RARC) with resolution steps'. The verb 'look up' indicates a retrieval operation. No creation, modification, deletion, execution, or financial transaction is mentioned.
Attacks that exploit this kind of access
Look up denial codes (CARC/RARC) with resolution steps. It is categorised as a Read tool in the Medical Billing MCP MCP Server, which means it retrieves data without modifying state.
Register the Medical Billing MCP server in PolicyLayer and add a rule for lookup_denial: 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 Medical Billing MCP. Nothing to install.
lookup_denial 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 lookup_denial 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 lookup_denial. 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.
lookup_denial is provided by the Medical Billing MCP server (kustode-ce/medical-billing-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.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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