addressbook_update · HashPilot MCP: Risk & Policy

WHAT IT DOES

What addressbook_update does on HashPilot

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

WHY IT NEEDS A POLICY

Why addressbook_update needs a policy

This tool creates or modifies data reversibly by updating a nickname field in a local address book. It does not execute transactions, delete data irreversibly, move funds, or have financial implications. The blast radius is minimal—a mistake would only affect a locally stored nickname, which can be easily corrected.

From the tool's definition Tool description states 'Update the nickname of an account in the address book.' The verb 'update' indicates modification of existing data. The scope is limited to nickname metadata, not account balances, contract code, or blockchain state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

addressbook_update Rate-limited

addressbook_update 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": {
    "addressbook_update": {
      "limits": [
        {
          "counter": "addressbook_update_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 HashPilot, so you can run agents against it safely.

FAQ

Questions about addressbook_update

What does the addressbook_update tool do? +

Update the nickname of an account in the address book. It is categorised as a Write tool in the HashPilot MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on addressbook_update? +

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

What risk level is addressbook_update? +

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

Can I rate-limit addressbook_update? +

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

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

addressbook_update is provided by the HashPilot MCP server (justmert/hashpilot). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.