add_user_book_read · Hardcover MCP: Risk & Policy

WHAT IT DOES

What add_user_book_read does on Hardcover

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

WHY IT NEEDS A POLICY

Why add_user_book_read needs a policy

This tool creates or modifies reading progress records in the user's library. While reversible (entries can be deleted via delete_user_book_read), it changes the state of user data. It does not delete data (Destructive), execute arbitrary code (Execute), move money (Financial), or merely retrieve information (Read). Write is the appropriate category.

From the tool's definition Tool performs 'Add a reading date or progress entry' and 'Updates active read' — these are create/modify operations on user library data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_user_book_read Rate-limited

add_user_book_read 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_user_book_read": {
      "limits": [
        {
          "counter": "add_user_book_read_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 Hardcover, so you can run agents against it safely.

FAQ

Questions about add_user_book_read

What does the add_user_book_read tool do? +

Add a reading date or progress entry. Updates active read if one exists. It is categorised as a Write tool in the Hardcover 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_user_book_read? +

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

What risk level is add_user_book_read? +

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

Can I rate-limit add_user_book_read? +

Yes. Add a rate_limit block to the add_user_book_read 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_user_book_read completely? +

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

add_user_book_read is provided by the Hardcover MCP server (kristianedlund/hardcover-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.