Processes and transforms JSON using jq expressions. Accepts JSON from a file path or inline string. Returns the transformed result.
AI agents invoke jq to trigger actions in Lint. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The tool executes arbitrary jq expressions against JSON data. While jq is primarily a query/transform language, it can execute complex logic and transformations. The ability to run arbitrary expressions elevates this beyond a simple read operation into Execute territory, though the blast radius is moderate since jq itself cannot perform destructive file operations or system calls.
From the tool's definition "Processes and transforms JSON using jq expressions" and "Returns the transformed result"
Documented attack patterns abuse exactly the kind of access jq gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Lint, and nothing reaches the server without passing your rules. This is the rule we recommend for jq:
{
"version": "1",
"default": "deny",
"tools": {
"jq": {
"limits": [
{
"counter": "jq_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}jq stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Processes and transforms JSON using jq expressions. Accepts JSON from a file path or inline string. Returns the transformed result. It is categorised as a Execute tool in the Lint MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Lint MCP server in PolicyLayer and add a rule for jq: 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 Lint. Nothing to install.
jq is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the jq 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 jq. 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.
jq is provided by the Lint MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Lint, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
202 Lint tools catalogued and risk-classified — across an index of 43,000+ MCP servers.