json_query
Runs a JSONPath query and returns the matching values with their concrete paths. Supports property access, array indexing (including negative indices), slices, wildcards, recursive descent (..) and filters ([?(@.price > 10)]). Pull three fields out of a large API response without carrying the who...
This record as markdown: /tools/com-fluentedi-tools/json-query.md
What json_query does on Tools
AI agents call json_query to retrieve information from Tools without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
json | object | Yes | The JSON document, as an object or a JSON string. |
path | string | Yes | JSONPath expression, e.g. "$.items[*].id" or "$..author". |
first_only | boolean | — | Return only the first match. |
Parameters from the server's own tool schema.
Why json_query is rated Low
Even though json_query only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Risk signalsAccepts file system path (path)
Attacks that exploit this kind of access
The rule that runs json_query safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Tools, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For json_query, this is the rule to start with:
json_query is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Tools, apply this rule, and every json_query call is checked against it from then on.
Questions about json_query
Runs a JSONPath query and returns the matching values with their concrete paths. Supports property access, array indexing (including negative indices), slices, wildcards, recursive descent (..) and filters ([?(@.price > 10)]). Pull three fields out of a large API response without carrying the whole document through context. It is categorised as a Read tool in the Tools MCP Server, which means it retrieves data without modifying state.
json_query accepts 3 parameters: json, path, first_only. Required: json, path. The full parameter table on this page comes from the server's own tool schema.
Register the Tools MCP server in PolicyLayer and add a rule for json_query: 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 Tools. Nothing to install.
json_query 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 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. 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 is provided by the Tools MCP server (https://fluentedi.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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