press_button

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

With no annotations, the description carries the full burden of behavioral disclosure. It only states the action and the button list, but fails to mention potential side effects (e.g., pressing POWER might lock the screen, BACK might exit an app, VOLUME_UP changes system volume). There is no mention of whether the action is synchronous, requires permissions, or what the return value is. This is a significant gap for a hardware interaction tool.

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 a single concise sentence that front-loads the primary action. The button list is embedded inline, which is efficient though slightly cluttered. No wasted words; it earns its place.

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 button-press tool, the description covers the basic action and parameter list. However, given the lack of annotations, it omits critical behavioral context such as side effects, potential blocking behavior, and whether it works on all Android versions. The description is minimally adequate but leaves an agent uncertain about consequences.

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?

The input schema already defines the button enum and a description for serial, giving 50% schema description coverage. The tool description merely repeats the button list without adding any semantic guidance on when to use each button or how they behave. It does not explain the serial parameter's purpose beyond what the schema says. The description adds no value beyond 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?

The description clearly states the action ('Press a hardware/navigation button') and enumerates the specific buttons it supports (HOME, BACK, etc.). This makes the tool's purpose unambiguous and distinct from siblings like tap (screen touch) and key_event (keyboard input). The verb+resource structure is precise.

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 no guidance on when to use this tool versus alternatives like tap, key_event, or swipe. It does not mention that hardware buttons may behave differently across devices or that some buttons (e.g., POWER) could trigger system-level actions. No context on use cases or exclusions is provided.

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