AI agents call is_holiday_today to retrieve information from Mcp Swiss without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries static holiday calendar data and returns information (holiday name or absence thereof). It performs no data creation, modification, deletion, or external action execution. No financial impact or destructive capability. This is a straightforward read/lookup operation with minimal blast radius if misused by an AI agent.
From the tool's definition Tool name 'is_holiday_today' and description 'Check whether today is a Swiss public holiday' indicate a query operation that retrieves holiday status information with no side effects or modifications.
Attacks that exploit this kind of access
Check whether today is a Swiss public holiday, optionally for a specific canton. Returns the holiday name if it is one. It is categorised as a Read tool in the Mcp Swiss MCP Server, which means it retrieves data without modifying state.
Register the Mcp Swiss MCP server in PolicyLayer and add a rule for is_holiday_today: 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 Mcp Swiss. Nothing to install.
is_holiday_today 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 is_holiday_today 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 is_holiday_today. 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.
is_holiday_today is provided by the Mcp Swiss MCP server (mcp-swiss). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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