Latest observed AQI for a US ZIP code. Returns one record per pollutant reported at the nearest site (typically O3 + PM2.5). Includes AQI value, category (Good / Moderate / etc.), reporting area, and timestamp.
Part of the Airnow server.
Free to start. No card required.
AI agents call current_by_zip to retrieve information from Airnow without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though current_by_zip only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"current_by_zip": {}
}
}See the full Airnow policy for all 24 tools.
These attack patterns abuse exactly the kind of access current_by_zip gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Latest observed AQI for a US ZIP code. Returns one record per pollutant reported at the nearest site (typically O3 + PM2.5). Includes AQI value, category (Good / Moderate / etc.), reporting area, and timestamp.. It is categorised as a Read tool in the Airnow MCP Server, which means it retrieves data without modifying state.
Register the Airnow MCP server in PolicyLayer and add a rule for current_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 Airnow. Nothing to install.
current_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 current_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 current_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.
current_by_zip is provided by the Airnow MCP server (https://gateway.pipeworx.io/airnow/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 24 Airnow tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.