jq
Processes and transforms JSON using jq expressions. Accepts JSON from a file path or inline string. Returns the transformed result.
This record as markdown: /tools/io-github-dave-london-docker/jq.md
What jq does on Docker
AI agents invoke jq to trigger actions in Docker. 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.
Why jq is rated High
jq executes arbitrary filter/transformation expressions against JSON data. While typically read-only in nature, jq expressions can be complex and the tool 'executes' an expression language. The blast radius is medium since it processes data but doesn't directly modify files or systems unless combined with shell redirection—though as a standalone MCP tool it appears to only return results.
From the tool's definition Processes and transforms JSON using jq expressions... Returns the transformed result.
Attacks that exploit this kind of access
The rule that runs jq safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Docker, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For jq, this is the rule to start with:
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.
The button opens the PolicyLayer dashboard: create your workspace, connect Docker, apply this rule, and every jq call is checked against it from then on.
Questions about jq
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 Docker MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Docker 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 Docker. 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 Docker MCP server (@paretools/docker). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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