Process JSON data using jq filter syntax without requiring approval.
AI agents invoke jq_query to trigger actions in MCP DevTools Server. 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.
jq is a JSON processor that executes filter programs/expressions against data. While typically used for read-like querying, jq supports complex operations including data transformation and can execute arbitrary filter logic. The 'without requiring approval' note suggests automated execution of arbitrary jq expressions, which elevates risk beyond a simple read operation.
From the tool's definition "Process JSON data using jq filter syntax" — jq supports arbitrary filter expressions including operations that can transform, extract, or manipulate data; "without requiring approval" indicates it runs without human confirmation
Documented attack patterns abuse exactly the kind of access jq_query gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP DevTools Server, and nothing reaches the server without passing your rules. This is the rule we recommend for jq_query:
{
"version": "1",
"default": "deny",
"tools": {
"jq_query": {
"limits": [
{
"counter": "jq_query_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}jq_query 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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Process JSON data using jq filter syntax without requiring approval. It is categorised as a Execute tool in the MCP DevTools Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the MCP DevTools Server MCP server in PolicyLayer and add a rule for jq_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 MCP DevTools Server. Nothing to install.
jq_query 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_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 jq_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.
jq_query is provided by the MCP DevTools Server MCP server (rshade/mcp-devtools-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP DevTools Server, 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.
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