watch_update · Stock MCP Server MCP: Risk & Policy

WHAT IT DOES

What watch_update does on Stock MCP Server

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

WHY IT NEEDS A POLICY

Why watch_update needs a policy

This tool modifies an existing watchlist entry by updating its name or observation rationale. It is a reversible write operation with no financial transactions, code execution, or irreversible deletions involved. The blast radius is low since it only affects a personal watchlist label/note.

From the tool's definition 更新观察股票（名称或观察理由）— 'update' of a watchlist entry (name or watch rationale)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

watch_update Rate-limited

watch_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": {
    "watch_update": {
      "limits": [
        {
          "counter": "watch_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 Stock MCP Server, so you can run agents against it safely.

FAQ

Questions about watch_update

What does the watch_update tool do? +

更新观察股票（名称或观察理由）. It is categorised as a Write tool in the Stock 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 watch_update? +

Register the Stock MCP Server MCP server in PolicyLayer and add a rule for watch_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 Stock MCP Server. Nothing to install.

What risk level is watch_update? +

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

Can I rate-limit watch_update? +

Yes. Add a rate_limit block to the watch_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 watch_update completely? +

Set action: deny in the PolicyLayer policy for watch_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 watch_update? +

watch_update is provided by the Stock MCP Server MCP server (kinmeic/stock-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.