ruff-format
Runs ruff format and returns structured results (files changed, file list).
This record as markdown: /tools/io-github-dave-london-pare-python/ruff-format.md
What ruff-format does on Python
AI agents call ruff-format to retrieve information from Python without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
diff | boolean | — | Show diff of formatting changes without applying (--diff) |
path | string | — | Project root path |
check | boolean | — | Check mode (report without modifying files) |
range | string | — | Line range for formatting (e.g. '10-20') |
config | string | — | Path to custom ruff config file |
compact | boolean | — | Prefer compact output |
exclude | array | — | File patterns to exclude from formatting |
noCache | boolean | — | Disable cache (--no-cache) |
preview | boolean | — | Enable preview formatting rules (--preview) |
isolated | boolean | — | Ignore all configuration files (--isolated) |
patterns | array | — | Files or directories to format (default: ["."]) |
lineLength | integer | — | Override the configured line length (--line-length) |
Parameters from the server's own tool schema.
Why ruff-format is rated Low
Even though ruff-format only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Risk signalsAccepts file system path (path) · High parameter count (16 properties)
Attacks that exploit this kind of access
The rule that runs ruff-format safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Python, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For ruff-format, this is the rule to start with:
ruff-format is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Python, apply this rule, and every ruff-format call is checked against it from then on.
Questions about ruff-format
Runs ruff format and returns structured results (files changed, file list). It is categorised as a Read tool in the Python MCP Server, which means it retrieves data without modifying state.
ruff-format accepts 12 parameters: diff, path, check, range, config, compact, exclude, noCache, preview, isolated, patterns, lineLength. The full parameter table on this page comes from the server's own tool schema.
Register the Python MCP server in PolicyLayer and add a rule for ruff-format: 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 Python. Nothing to install.
ruff-format is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the ruff-format 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-format. 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-format is provided by the Python MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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