Get the fields returned for annotators including data type, name, human readable title, and description (if available)
AI agents call get_fields to retrieve information from OpenCRAVAT without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves field metadata and schema information about available annotators. It performs no data modification, deletion, or execution of external operations. The operation is informational and returns descriptive data only, making it a standard Read category tool with low severity and low blast radius if misused.
From the tool's definition Tool name 'get_fields' combined with description 'Get the fields returned for annotators including data type, name, human readable title, and description (if available)' indicates a read-only query operation that retrieves schema or metadata information…
Documented attack patterns abuse exactly the kind of access get_fields gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OpenCRAVAT, and nothing reaches the server without passing your rules. This is the rule we recommend for get_fields:
{
"version": "1",
"default": "deny",
"tools": {
"get_fields": {}
}
}get_fields is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get the fields returned for annotators including data type, name, human readable title, and description (if available). It is categorised as a Read tool in the OpenCRAVAT MCP Server, which means it retrieves data without modifying state.
Register the OpenCRAVAT MCP server in PolicyLayer and add a rule for get_fields: 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 OpenCRAVAT. Nothing to install.
get_fields 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 get_fields 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 get_fields. 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.
get_fields is provided by the OpenCRAVAT MCP server (karchinlab/oc-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from OpenCRAVAT, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
7 OpenCRAVAT tools catalogued and risk-classified — across an index of 43,000+ MCP servers.