mobile_open_urlOpens a specified URL in the browser on a chosen iOS or Android device, enabling agents to launch web pages during mobile automation.
Open a URL in browser on device
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | The URL to open | |
| device | Yes | The device identifier to use. Use mobile_list_available_devices to find which devices are available to you. |
Changes observed during successful MCP inspections.
v1.0.6Input schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"v1.0.0Input schema / additionalPropertiesRemoved value: -falseInput schema / properties / deviceAdded value: +{
+ "description": "The device identifier to use. Use mobile_list_available_devices to find which devices are available to you.",
+ "type": "string"
+}Input schema / requiredPrevious value: -[
- "url"
-]New value: +[
+ "device",
+ "url"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, openWorldHint=true, and destructiveHint=false, so the safety profile is covered by structured data. The description adds nothing beyond that — no mention that this launches an external browser, makes network requests, or affects foreground state (which mobile_get_foreground_app would observe).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single short sentence with the action front-loaded and no filler. Efficient, though it leans on terseness rather than structured completeness.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple two-parameter, well-documented tool with no output schema, the minimal description is survivable, but it omits the openWorld/network side effects and any interaction with sibling navigation tools, leaving the agent to infer behavior from annotations alone.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% and both parameters are documented in-schema, including the device-discovery tip. The description adds no format, constraint, or example detail beyond what the schema provides, so the baseline 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a clear verb (open), resource (URL), and context (in browser on device), which distinguishes it from the other mobile_* action tools. It does not explicitly contrast with siblings like mobile_launch_app, but the purpose is unambiguous.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance on when to use this versus alternatives such as mobile_launch_app or the clicking/typing tools. The only procedural hint (use mobile_list_available_devices) lives in the schema parameter description, not the tool description.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.