resolve_user · ZulipChat MCP Server MCP: Risk & Policy

WHAT IT DOES

What resolve_user does on ZulipChat MCP Server

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

WHY IT NEEDS A POLICY

Why resolve_user needs a policy

An AI agent can call resolve_user faster than any human can review — one bad instruction and it creates or modifies resources in ZulipChat MCP Server by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

resolve_user Rate-limited

resolve_user 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": {
    "resolve_user": {
      "limits": [
        {
          "counter": "resolve_user_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 ZulipChat MCP Server, so you can run agents against it safely.

FAQ

Questions about resolve_user

What does the resolve_user tool do? +

Resolve display name to email with fuzzy matching. It is categorised as a Write tool in the ZulipChat 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 resolve_user? +

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

What risk level is resolve_user? +

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

Can I rate-limit resolve_user? +

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

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

resolve_user is provided by the ZulipChat MCP Server MCP server (pypi:zulipchat-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.