open

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full behavioral burden but only says what is opened. It does not disclose whether the call blocks until load completes, what happens if an app is already running, or whether a leased session is required — all material for an automation action.

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 front-loaded sentence with no waste. Its terseness is a virtue structurally, even though the content gaps are handled in other dimensions.

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?

An output schema exists so return values need not be described, but for a 2-required-parameter tool with 0% schema coverage and zero annotations, the definition leaves the 'phone' parameter, the lease prerequisite, and blocking behavior unexplained.

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 description coverage is 0% for both parameters, so the description must compensate. It partially explains 'target' (URL or package name) but never mentions 'phone' at all, leaving a required parameter completely undocumented.

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 ('open') and two distinct resources (http(s) URL, app package name), which is enough to separate it from sibling input actions like tap/type/swipe. It does not, however, name any sibling or explain how it relates to the lease/release session tools.

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?

The description offers no when-to-use guidance, no prerequisites, and no alternatives. Given siblings include lease/release, an agent cannot tell whether the device must be leased before calling open, which is exactly the routing question this description should answer.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.