add_to_collection · Krill To MCP Server MCP: Risk & Policy

WHAT IT DOES

What add_to_collection does on Krill To MCP Server

AI agents use add_to_collection 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 add_to_collection needs a policy

This tool modifies user data (bookmark collections) by adding items to them. While reversible (the operation could be undone by removing the bookmark), it changes the state of user bookmarks and collections. It does not execute arbitrary code, delete data irreversibly, or involve financial transactions.

From the tool's definition The tool name 'add_to_collection' and description 'Add a bookmark to a collection' indicate it creates or modifies data by adding a bookmark to an existing collection. This is a reversible write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_to_collection Rate-limited

add_to_collection 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_to_collection": {
      "limits": [
        {
          "counter": "add_to_collection_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 add_to_collection

What does the add_to_collection tool do? +

Add a bookmark to a collection. 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 add_to_collection? +

Register the Krill To MCP Server MCP server in PolicyLayer and add a rule for add_to_collection: 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 add_to_collection? +

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

Can I rate-limit add_to_collection? +

Yes. Add a rate_limit block to the add_to_collection 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_to_collection completely? +

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

add_to_collection 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.