Open a URL on the device: custom schemes (myapp://...), universal links, or exp:// links. The primary way to drive app navigation from outside the app.
AI agents invoke open_url to trigger actions in React Native Dev. 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.
This tool triggers an external operation on a device by opening a URL, which can invoke custom app schemes, universal links, or Expo links. It causes real side effects (app navigation, deep linking) that depend on the URL argument provided.
From the tool's definition 'Open a URL on the device: custom schemes (myapp://...), universal links, or exp:// links. The primary way to drive app navigation from outside the app.'
Attacks that exploit this kind of access
Open a URL on the device: custom schemes (myapp://...), universal links, or exp:// links. The primary way to drive app navigation from outside the app. It is categorised as a Execute tool in the React Native Dev MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the React Native Dev 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 React Native Dev. 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 React Native Dev MCP server (luizhbesper/react-native-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
open_url is one line of React Native Dev's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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