create_shelf · Shelv MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_shelf does on Shelv MCP Server

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

WHY IT NEEDS A POLICY

Why create_shelf needs a policy

This tool creates a new shelf resource by uploading a PDF file. This is a Write operation as it creates data persistently but reversibly. Severity is medium because creating shelves has limited blast radius—it consumes storage and could clutter the system, but doesn't corrupt existing data, execute arbitrary commands, or move funds. Confidence is high because the description is clear about the intent.

From the tool's definition Tool description states 'create a shelf' which creates new data/resources. The operation is reversible (shelves can be deleted) and does not irreversibly destroy data or execute arbitrary code.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_shelf Rate-limited

create_shelf 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": {
    "create_shelf": {
      "limits": [
        {
          "counter": "create_shelf_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 Shelv MCP Server, so you can run agents against it safely.

FAQ

Questions about create_shelf

What does the create_shelf tool do? +

Upload a local PDF and create a shelf. It is categorised as a Write tool in the Shelv MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_shelf? +

Register the Shelv MCP Server MCP server in PolicyLayer and add a rule for create_shelf: 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 Shelv MCP Server. Nothing to install.

What risk level is create_shelf? +

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

Can I rate-limit create_shelf? +

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

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

create_shelf is provided by the Shelv MCP Server MCP server (shelv-dev/shelv-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.