AI agents call get_weather_by_zip to retrieve information from OpenWeatherMap MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves weather data for a given ZIP code without modifying, deleting, or executing external operations. It is a pure data read operation with no side effects, minimal blast radius if misused (worst case: excessive API calls), and no financial or destructive implications. Low severity because weather data access poses minimal security risk.
From the tool's definition Tool name 'get_weather_by_zip' and sibling tools (get_air_quality, get_current_weather, get_forecast, search_location) are all retrieval operations.
Documented attack patterns abuse exactly the kind of access get_weather_by_zip gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OpenWeatherMap MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for get_weather_by_zip:
{
"version": "1",
"default": "deny",
"tools": {
"get_weather_by_zip": {}
}
}get_weather_by_zip is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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get_weather_by_zip. It is categorised as a Read tool in the OpenWeatherMap MCP Server MCP Server, which means it retrieves data without modifying state.
Register the OpenWeatherMap MCP Server MCP server in PolicyLayer and add a rule for get_weather_by_zip: 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 OpenWeatherMap MCP Server. Nothing to install.
get_weather_by_zip is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_weather_by_zip 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.
Set action: deny in the PolicyLayer policy for get_weather_by_zip. 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.
get_weather_by_zip is provided by the OpenWeatherMap MCP Server MCP server (jezweb/weather-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from OpenWeatherMap MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
5 OpenWeatherMap MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.