Perform generic groupby and aggregation operations on any data type. Supports sum, count, avg, mean, min, max, std aggregations.
AI agents call aggregate_parquet to retrieve information from Parquet MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Aggregation operations are inherently read-only transformations that summarize data without side effects. No data is created, modified, deleted, or irreversibly changed. The tool computes derived statistics from existing Parquet data, which is characteristic of Read category tools. Severity is low because misuse would only return incorrect statistics, not compromise data integrity or trigger external actions.
From the tool's definition Tool performs 'groupby and aggregation operations' with functions like 'sum, count, avg, mean, min, max, std' — these are read-only analytical queries that compute statistics over data without modifying or deleting underlying records.
Attacks that exploit this kind of access
Perform generic groupby and aggregation operations on any data type. Supports sum, count, avg, mean, min, max, std aggregations. It is categorised as a Read tool in the Parquet MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Parquet MCP Server MCP server in PolicyLayer and add a rule for aggregate_parquet: 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 Parquet MCP Server. Nothing to install.
aggregate_parquet 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 aggregate_parquet 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 aggregate_parquet. 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.
aggregate_parquet is provided by the Parquet MCP Server MCP server (markmhendrickson/mcp-server-parquet). 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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