Query a JSON file using JSONPath. Use to get values precisely from large JSON files.
AI agents call json_query_jsonpath to retrieve information from JSON Query MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and extracts data from JSON files without modifying, deleting, or executing code. JSONPath is a standardized query language for read-only data access. The blast radius of misuse is minimal—an agent could only access whatever data is already present in the JSON file, posing no destructive, financial, or code execution risk.
From the tool's definition Tool description states it is used to "get values precisely from large JSON files" and "query a JSON file using JSONPath." The JSONPath mechanism is inherently a query/retrieval operation with no write, delete, or execution capability.
Documented attack patterns abuse exactly the kind of access json_query_jsonpath gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and JSON Query MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for json_query_jsonpath:
{
"version": "1",
"default": "deny",
"tools": {
"json_query_jsonpath": {}
}
}json_query_jsonpath is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Query a JSON file using JSONPath. Use to get values precisely from large JSON files. It is categorised as a Read tool in the JSON Query MCP MCP Server, which means it retrieves data without modifying state.
Register the JSON Query MCP server in PolicyLayer and add a rule for json_query_jsonpath: 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 JSON Query MCP. Nothing to install.
json_query_jsonpath 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 json_query_jsonpath 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 json_query_jsonpath. 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.
json_query_jsonpath is provided by the JSON Query MCP server (mgraczyk/json-query-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from JSON Query MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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3 JSON Query MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.