screen_state

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It clearly discloses that the tool is purely informational, only shows the current state, and does not attempt to circumvent locks, which addresses the main risk for a screen-state query. It does not discuss permissions or side effects, but for a read-only state query this is reasonably transparent.

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 two short sentences with no filler. It front-loads the core state information and then adds a concise, important caveat about not being a lock-bypass tool.

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?

An output schema exists, so return values do not need to be described. The main gap is that the optional serial parameter is undocumented in both the schema and the description, and there is no guidance on when to pass it; otherwise the tool is a simple read-only query.

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 schema has 0% description coverage and the only parameter, serial, is never mentioned in the description. The agent is left to infer what serial means or whether omitting it targets a default/current device, so the description adds no value for parameter understanding.

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 that the tool reports the current screen state: on/off and whether it is locked. It identifies the resource ('screen') and frames the operation as an informative query, which distinguishes it from capture tools like screenshot and screen_record, though it does not name those siblings.

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 this is an informative query and is NOT suitable for bypassing a lock, which provides a useful exclusion. However, it does not name any alternative tools or state when screen_state should be preferred over related tools such as ui_dump or screenshot, so the guidance is partial.

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