fhir.create · Fhir MCP: Risk & Policy

WHAT IT DOES

What fhir.create does on FhirMCP

AI agents use fhir.create to create or update resources in FhirMCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your FhirMCP environment.

WHY IT NEEDS A POLICY

Why fhir.create needs a policy

This tool creates new healthcare data records reversibly. It is Write rather than Destructive because creation is reversible (records can be deleted/updated). It is not Financial, Execute, or Read.

From the tool's definition Tool name 'fhir.create' and description 'Create a new FHIR resource' directly indicate creation of new data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

fhir.create Rate-limited

fhir.create stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "fhir.create": {
      "limits": [
        {
          "counter": "fhir.create_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches FhirMCP, so you can run agents against it safely.

FAQ

Questions about fhir.create

What does the fhir.create tool do? +

Create a new FHIR resource (requires write permissions). It is categorised as a Write tool in the FhirMCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on fhir.create? +

Register the Fhir MCP server in PolicyLayer and add a rule for fhir.create: 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 FhirMCP. Nothing to install.

What risk level is fhir.create? +

fhir.create is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit fhir.create? +

Yes. Add a rate_limit block to the fhir.create 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.

How do I block fhir.create completely? +

Set action: deny in the PolicyLayer policy for fhir.create. 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.

What MCP server provides fhir.create? +

fhir.create is provided by the Fhir MCP server (xsovx/fhir-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.