press

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

With no annotations, the description carries the burden and does disclose the return contract ('Pressed' or 'Could not press'), which usefully signals that failure is possible and confirmation is weak. It does not state prerequisites (accessibility service, screen state) or whether back can discard unsaved state, leaving some behavioral gaps.

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?

One dense sentence of value definitions, one routing hint, one return-value note. Every clause earns its place and the core action is front-loaded.

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?

A single-parameter tool with no output schema; the description supplies value semantics, an alternative route, and the return strings an agent needs to interpret results. Nothing material is missing.

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 0% and the schema only lists bare enum strings, so the description must compensate — and it does, defining the real-world effect of every one of the five values rather than repeating the enum tokens.

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?

Specific verb (press) plus resource (Android system buttons) with all five button values enumerated and explained in plain language. An agent can distinguish it from long_press, tap, and scroll from the text alone.

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?

Each button value carries its own when-to-use gloss (back closes dialogs/keyboard, home goes to home screen, etc.), and it explicitly names an alternative and the condition that selects it: 'To switch apps, open_app is faster than home and recents.'

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