Press

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

With no annotations, the description carries the full burden. It states the action (press) and the targets (home/back/enter) but does not disclose any side effects, permissions, or behavior for invalid inputs. For a simple action this is adequate but minimal; no contradiction with annotations (none provided).

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 sentence with two clauses: the action and the usage note. It is front-loaded with the core function and wastes no words. Perfectly concise.

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 legacy action, the description covers the core purpose, the button values, and usage preference. The 'device' parameter is not explained, but it is optional and likely obvious from context. With an output schema present, return values are not needed. Overall adequate, with a minor gap.

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 description adds meaning for the 'button' parameter by specifying the allowed values (home, back, enter), which the schema does not enumerate. However, it does not explain the 'device' parameter, leaving it to inference. Since schema coverage is 0%, the description partially compensates but not fully.

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?

Description clearly states the tool presses home, back, or enter – a specific verb and resource. It also names the preferred alternatives (press_home/back/enter), distinguishing it from siblings. This is explicit and unambiguous.

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 explicitly says 'kept for old clients; prefer press_home/back/enter', giving clear when-to-use and when-not-to-use guidance. It tells the agent to use this only for legacy compatibility and prefer the dedicated tools otherwise.

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