open_url
Open a URL or file association through Windows Shell, optionally focusing a matching window.
This record as markdown: /tools/mcp-control-plane/open-url.md
What open_url does on Mcp Control Plane
AI agents invoke open_url to trigger actions in Mcp Control Plane. 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 open_url is rated High
This tool executes an action via Windows Shell to open arbitrary URLs or file associations. An AI agent could misuse it to open malicious URLs, trigger file handler exploits, or launch unintended applications. The effects depend on the arguments provided (the URL/file), making it Execute category with high severity due to the broad attack surface of Windows Shell execution.
From the tool's definition Open a URL or file association through Windows Shell, optionally focusing a matching window.
Attacks that exploit this kind of access
The rule that runs open_url safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Mcp Control Plane, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For open_url, this is the rule to start with:
open_url 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 Mcp Control Plane, apply this rule, and every open_url call is checked against it from then on.
Questions about open_url
Open a URL or file association through Windows Shell, optionally focusing a matching window. It is categorised as a Execute tool in the Mcp Control Plane MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Mcp Control Plane MCP server in PolicyLayer and add a rule for open_url: 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 Mcp Control Plane. Nothing to install.
open_url 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 open_url 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 open_url. 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.
open_url is provided by the Mcp Control Plane MCP server (albertik322-sudo/mcp-control-plane). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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