AI agents call xbrl_calculation_tree to retrieve information from Arelle without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Despite the empty description, the naming pattern aligns with other Read tools on this server (xbrl_browse_taxonomy, xbrl_concept_details, xbrl_dimension_structure). A 'calculation tree' operation most likely retrieves and displays the hierarchical structure of calculations within an XBRL instance, which is a non-destructive query operation.
From the tool's definition Tool name 'xbrl_calculation_tree' and context within a filing analysis/validation server suggest querying or traversing calculation relationships in XBRL documents. No action verbs like 'create', 'delete', 'execute', or 'modify' appear in the name.
Attacks that exploit this kind of access
xbrl_calculation_tree. It is categorised as a Read tool in the Arelle MCP Server, which means it retrieves data without modifying state.
Register the Arelle MCP server in PolicyLayer and add a rule for xbrl_calculation_tree: 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 Arelle. Nothing to install.
xbrl_calculation_tree 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 xbrl_calculation_tree 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 xbrl_calculation_tree. 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.
xbrl_calculation_tree is provided by the Arelle MCP server (thekinghippopotamus/arelle-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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