screen_off

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

No annotations contradict the description, and annotations already declare readOnlyHint=false and destructiveHint=false, so the agent knows this is a mutating but non-destructive action. However, the description adds no behavioral detail beyond what annotations provide—no mention of effects on running apps, whether the screen can be turned back on, or device state implications.

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 sentence, zero waste, appropriately sized for a simple tool action. Nothing extraneous.

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?

This is a very simple tool with one optional parameter, an output schema, and annotations covering the safety profile. For such a low-complexity tool, the description is minimally adequate. However, it doesn't mention what the output/return indicates (success/failure) or any failure conditions, though the output schema may cover this.

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 100%, with the single 'serial' parameter documented as 'Device serial number'. The description adds no further meaning beyond the schema. Baseline 3 is appropriate when the schema fully documents parameters and there's only one simple parameter.

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 'Turn the device screen off' has a clear verb+resource and states the action. However, it doesn't distinguish from the sibling tool screen_on beyond the obvious inverse relationship, and there's no detail about what state transitions occur.

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?

No guidance on when to use this tool vs alternatives. It doesn't say whether screen_on should be used for the reverse, whether there are prerequisites (e.g., screen must be on), or any conditions where this would fail. The sibling screen_on exists but no cross-reference is made.

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