[FacturaHub] Get the currently open cash register. Returns null if no register is open. Use this to check POS status before adding sales.
AI agents call get_open_register to retrieve information from FacturaHub MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
get_open_register queries the current state of a cash register system and returns data (register details or null). It performs no modifications, deletions, or external operations. While it relates to financial systems, it is purely informational retrieval with no financial transactions or money movement.
From the tool's definition Tool description states 'Get the currently open cash register. Returns null if no register is open.' This is a retrieval operation with no side effects. The description explicitly indicates it checks status without modifying state.
Attacks that exploit this kind of access
[FacturaHub] Get the currently open cash register. Returns null if no register is open. Use this to check POS status before adding sales. It is categorised as a Read tool in the FacturaHub MCP Server MCP Server, which means it retrieves data without modifying state.
Register the FacturaHub MCP Server MCP server in PolicyLayer and add a rule for get_open_register: 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 FacturaHub MCP Server. Nothing to install.
get_open_register 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_open_register 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_open_register. 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_open_register is provided by the FacturaHub MCP Server MCP server (santy1422/facturahub-mcp). 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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