add_instrument · Redcap MCP: Risk & Policy

WHAT IT DOES

What add_instrument does on Redcap

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

WHY IT NEEDS A POLICY

Why add_instrument needs a policy

Adding an instrument in REDCap creates or modifies project configuration in a reversible way (instruments can be deleted or modified), making this a Write operation rather than Execute. However, severity is high rather than medium because instruments define data collection structures in a research context, and unintended instrument creation could affect study operations and data integrity.

From the tool's definition Tool name 'add_instrument' indicates creation of a new instrument (survey/form) within a REDCap project. The server context shows tools like 'delete_instrument', 'clone_instrument', 'assign_instrument_to_event' and explicit destructive operations…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_instrument Rate-limited

add_instrument 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": {
    "add_instrument": {
      "limits": [
        {
          "counter": "add_instrument_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 Redcap, so you can run agents against it safely.

FAQ

Questions about add_instrument

What does the add_instrument tool do? +

add_instrument. It is categorised as a Write tool in the Redcap MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_instrument? +

Register the Redcap MCP server in PolicyLayer and add a rule for add_instrument: 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 Redcap. Nothing to install.

What risk level is add_instrument? +

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

Can I rate-limit add_instrument? +

Yes. Add a rate_limit block to the add_instrument 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 add_instrument completely? +

Set action: deny in the PolicyLayer policy for add_instrument. 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 add_instrument? +

add_instrument is provided by the Redcap MCP server (msicilia/mcp-server-redcap). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.