update_bookmark · Krill To MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_bookmark does on Krill To MCP Server

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

WHY IT NEEDS A POLICY

Why update_bookmark needs a policy

The tool creates or modifies data in a reversible manner (updating bookmark metadata, collections, or notes), which is characteristic of Write operations. The blast radius is moderate — misuse could alter user's saved bookmarks and collections, but changes are reversible through further updates.

From the tool's definition Tool name is 'update_bookmark' and description states 'Update a bookmark' — this modifies existing bookmark data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_bookmark Rate-limited

update_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": {
    "update_bookmark": {
      "limits": [
        {
          "counter": "update_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 Krill To MCP Server, so you can run agents against it safely.

FAQ

Questions about update_bookmark

What does the update_bookmark tool do? +

Update a bookmark. It is categorised as a Write tool in the Krill To 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 update_bookmark? +

Register the Krill To MCP Server MCP server in PolicyLayer and add a rule for update_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 Krill To MCP Server. Nothing to install.

What risk level is update_bookmark? +

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

Can I rate-limit update_bookmark? +

Yes. Add a rate_limit block to the update_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 update_bookmark completely? +

Set action: deny in the PolicyLayer policy for update_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 update_bookmark? +

update_bookmark is provided by the Krill To MCP Server MCP server (krillto/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.