phone_openLaunch an installed Android app by package name, open a URL or deep link, or go to Settings, targeting a specific device when multiple are connected.
Open an installed app by package name (e.g. com.android.chrome), a URL or deep link (myapp://route), or "settings".
| Name | Required | Description | Default |
|---|---|---|---|
| serial | No | Which device to use. Only needed when several are connected. | |
| target | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full disclosure burden. It does not say what happens when the package is not installed, whether the call blocks until the app is in the foreground, whether it returns a success/failure signal, or how unresolvable deep links are handled.
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 sentence with no wasted words, with the primary parameter's accepted formats front-loaded and illustrated by examples.
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 two-parameter, no-annotation, no-output-schema tool, the description explains the input well but leaves out failure behavior, return semantics, and device targeting implications when `serial` is supplied. Adequate to invoke, but incomplete for handling outcomes.
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 only 50%: the `target` parameter has no schema description, and the description compensates well by enumerating its accepted forms (package name with example, URL, deep-link scheme, literal "settings"). The `serial` parameter's meaning is already covered in the schema.
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 specific verb and resource (open an installed app / URL / deep link) and gives concrete examples. It does not name any sibling tool, but the scope is narrow enough to distinguish it from phone_install or phone_shell by intent.
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?
Usage is only implied: 'Open an installed app' suggests it is for launching, not installing or shelling. There is no explicit when-to-use vs. phone_shell or phone_start, and no stated preconditions such as the app already being installed.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.