add_bookmark · Readbook MCP Server MCP: Risk & Policy

WHAT IT DOES

What add_bookmark does on Readbook MCP Server

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

WHY IT NEEDS A POLICY

Why add_bookmark needs a policy

This tool creates or adds a new bookmark, which is a reversible write operation. It does not read data (Read), execute arbitrary code (Execute), irreversibly delete data (Destructive), or involve financial transactions (Financial). The action is non-destructive and can be undone by removing the bookmark. Severity is low because misuse would only add unwanted bookmarks, causing minimal harm to the reading experience.

From the tool's definition Tool name 'add_bookmark' and description '在指定位置添加书签' (add bookmark at specified location) indicate creation of a new bookmark entry.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_bookmark Rate-limited

add_bookmark 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_bookmark": {
      "limits": [
        {
          "counter": "add_bookmark_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 Readbook MCP Server, so you can run agents against it safely.

FAQ

Questions about add_bookmark

What does the add_bookmark tool do? +

在指定位置添加书签. It is categorised as a Write tool in the Readbook 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 add_bookmark? +

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

What risk level is add_bookmark? +

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

Can I rate-limit add_bookmark? +

Yes. Add a rate_limit block to the add_bookmark 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_bookmark completely? +

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

add_bookmark is provided by the Readbook MCP Server MCP server (mkafw/readbook-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.