AI agents call get_acl_rule to retrieve information from Gcalendar without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves access control list rule information from Google Calendar. It performs a read-only query operation with no side effects, no data modification, and no capability to delete or execute actions. The minimal blast radius of misuse would be unauthorized visibility into calendar sharing rules, but not the ability to change them.
From the tool's definition Tool name 'get_acl_rule' and description 'Get an ACL rule' indicate data retrieval without modification. The verb 'Get' is explicitly a Read operation that queries existing ACL rule information.
Attacks that exploit this kind of access
Get an ACL rule. It is categorised as a Read tool in the Gcalendar MCP Server, which means it retrieves data without modifying state.
Register the Gcalendar MCP server in PolicyLayer and add a rule for get_acl_rule: 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 Gcalendar. Nothing to install.
get_acl_rule 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_acl_rule 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_acl_rule. 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_acl_rule is provided by the Gcalendar MCP server (sandeepmallareddy/gcalendar-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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