AI agents call getNow to retrieve information from Cal Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns system time information with no side effects, no code execution, and no data modification. It is a straightforward read operation that poses minimal security risk. The severity is low because misuse (e.g., an agent repeatedly calling it) would only result in benign timestamp queries with no harmful consequences.
From the tool's definition Tool name 'getNow' and description 'Get the current timestamp' indicate a read-only operation that retrieves the current system time without modifying or executing any operations.
Documented attack patterns abuse exactly the kind of access getNow gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Cal Server, and nothing reaches the server without passing your rules. This is the rule we recommend for getNow:
{
"version": "1",
"default": "deny",
"tools": {
"getNow": {}
}
}getNow is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get the current timestamp. It is categorised as a Read tool in the Cal Server MCP Server, which means it retrieves data without modifying state.
Register the Cal Server MCP server in PolicyLayer and add a rule for getNow: 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 Cal Server. Nothing to install.
getNow 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 getNow 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 getNow. 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.
getNow is provided by the Cal Server MCP server (pwh-pwh/cal-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Cal Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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4 Cal Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.