AI agents use browser_print_pdf to create or update resources in Byob — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Byob environment.
Although the description notes it is 'read'-focused in returning a path rather than data, the core action is file creation/writing to disk. This is a Write operation because it creates a persistent artifact (a PDF file) on the filesystem.
From the tool's definition The tool 'browser_print_pdf' performs a file write operation—it 'Save[s] the current page as a PDF file' and 'Returns the file PATH'. This creates a new file on the user's filesystem.
Attacks that exploit this kind of access
Save the current page as a PDF file. Returns the file PATH (not data) — read. It is categorised as a Write tool in the Byob MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Byob MCP server in PolicyLayer and add a rule for browser_print_pdf: 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 Byob. Nothing to install.
browser_print_pdf 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 browser_print_pdf 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 browser_print_pdf. 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.
browser_print_pdf is provided by the Byob MCP server (wxtsky/byob). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.