button

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

With no annotations provided, the description fully carries the behavioral burden. It discloses platform-specific event injection behavior (iOS Down/Up vs Android adb keyevent), unsupported-button rejection, the return value shape, and failure conditions when the backend is unreachable. This is exceptionally transparent for a tool with no annotations.

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?

The description is detailed but every sentence earns its place: platform behavior, supported buttons, usage intent, return value, and failure modes. It is front-loaded with the core action and structured logically, making it easy for an agent to parse quickly.

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?

Despite having no output schema and no annotations, the description covers return format, failure conditions, platform specifics, and supported values. Given the moderate complexity of this tool, nothing essential is missing for an agent to select and invoke it correctly.

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 the schema already describes both parameters with useful descriptions. The description goes beyond the schema by explaining platform-specific meaning of the button enum, which buttons are rejected on which platforms, and how the press is actually injected. This adds genuine value beyond the structured field descriptions.

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?

The description states a specific verb ('Press') and resource ('device hardware button'), with platform scope explicitly covered. It clearly distinguishes itself from sibling gesture and keyboard tools by focusing on hardware buttons and even gives platform-specific examples.

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 provides an explicit usage sentence: 'Use when you need to trigger hardware button events.' It also clarifies platform-dependent behavior and which buttons are rejected, giving practical guidance. It does not explicitly mention alternatives like gesture-tap or keyboard, but the hardware-button focus makes the intended use clear.

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