hadolint
Runs Hadolint (Dockerfile linter) and returns structured diagnostics (file, line, rule, severity, message).
This record as markdown: /tools/io-github-dave-london-docker/hadolint.md
What hadolint does on Docker
AI agents invoke hadolint 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 hadolint is rated High
The tool runs an external program (Hadolint) which constitutes executing a process. While it only performs read/analysis of a Dockerfile and returns diagnostics without modifying data, the act of running an external executable places it in the Execute category rather than Read. Misuse risk is medium since it could be pointed at arbitrary files on the filesystem.
From the tool's definition 'Runs Hadolint (Dockerfile linter)' — the tool executes an external linter process against a file
Attacks that exploit this kind of access
The rule that runs hadolint 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 hadolint, this is the rule to start with:
hadolint 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 hadolint call is checked against it from then on.
Questions about hadolint
Runs Hadolint (Dockerfile linter) and returns structured diagnostics (file, line, rule, severity, message). 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 hadolint: 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.
hadolint 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 hadolint 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 hadolint. 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.
hadolint 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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