construct_narrow · ZulipChat MCP Server MCP: Risk & Policy

WHAT IT DOES

What construct_narrow does on ZulipChat MCP Server

AI agents invoke construct_narrow to trigger actions in ZulipChat MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why construct_narrow needs a policy

construct_narrow triggers real processes with real consequences. An agent gone sideways doesn't fire it once — it starts dozens of builds, sends mass notifications, or burns through compute before anyone looks up.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

construct_narrow Rate-limited

construct_narrow stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "construct_narrow": {
      "limits": [
        {
          "counter": "construct_narrow_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-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 construct_narrow

What does the construct_narrow tool do? +

Build a narrow filter for Zulip API. It is categorised as a Execute tool in the ZulipChat MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on construct_narrow? +

Register the ZulipChat MCP Server MCP server in PolicyLayer and add a rule for construct_narrow: 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 construct_narrow? +

construct_narrow is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit construct_narrow? +

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

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

construct_narrow 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.