ruff-check
Runs ruff check and returns structured lint diagnostics (file, line, code, message).
This record as markdown: /tools/io-github-dave-london-cargo/ruff-check.md
What ruff-check does on Cargo
AI agents invoke ruff-check to trigger actions in Cargo. 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 ruff-check is rated High
The tool executes the ruff linter as an external process against code files. While it only reads/analyzes code and returns diagnostics without modifying files, it triggers an external operation (running a subprocess). This fits Execute rather than Read since it runs an external tool/command. Severity is medium as misuse could analyze arbitrary files on the filesystem.
From the tool's definition Runs ruff check and returns structured lint diagnostics
Attacks that exploit this kind of access
The rule that runs ruff-check safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Cargo, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For ruff-check, this is the rule to start with:
ruff-check 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 Cargo, apply this rule, and every ruff-check call is checked against it from then on.
Questions about ruff-check
Runs ruff check and returns structured lint diagnostics (file, line, code, message). It is categorised as a Execute tool in the Cargo MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Cargo MCP server in PolicyLayer and add a rule for ruff-check: 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 Cargo. Nothing to install.
ruff-check 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 ruff-check 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 ruff-check. 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.
ruff-check is provided by the Cargo MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
More on Cargo, and thousands of servers like it.
Across the catalogue