biome-format
Formats files with Biome (format --write) and returns a structured list of changed files.
This record as markdown: /tools/io-github-dave-london-go/biome-format.md
What biome-format does on Go
AI agents use biome-format to create or update resources in Go, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Go environment.
Why biome-format is rated Medium
This tool modifies files on disk by applying code formatting (a reversible operation). While formatting can be undone by version control or manual reversal, the tool directly overwrites file contents. This is a Write action rather than Read (it modifies, not just queries) or Destructive (formatting is reversible and doesn't delete data).
From the tool's definition The tool description explicitly states it "Formats files with Biome (format --write) and returns a structured list of changed files." The --write flag indicates in-place modification of files, and 'format' operations reversibly change file contents.
Attacks that exploit this kind of access
The rule that runs biome-format safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Go, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For biome-format, this is the rule to start with:
biome-format stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Go, apply this rule, and every biome-format call is checked against it from then on.
Questions about biome-format
Formats files with Biome (format --write) and returns a structured list of changed files. It is categorised as a Write tool in the Go MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Go MCP server in PolicyLayer and add a rule for biome-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 Go. Nothing to install.
biome-format is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the biome-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 biome-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.
biome-format is provided by the Go 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 Go, and thousands of servers like it.
This server
Across the catalogue