screen_info

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

No annotations are provided, so the description carries the burden, but it is inherently a non-mutating info query and the text discloses the returned dimensions including the real-vs-screenshot-space distinction, which is genuinely useful. It stops short of stating that it takes no arguments or is side-effect free.

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 tight sentence with no filler, and the most important item (screen size in both spaces) is front-loaded. It could be marginally clearer about what 'scale' means, but it wastes nothing.

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?

With an output schema present, the description need not enumerate return fields, and it sensibly summarizes them. For a zero-argument info tool this is close to complete; only the relationship to cursor_position is left unaddressed.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a parameterless tool applies. The description correctly focuses on the return payload instead.

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 names the exact data the tool returns — screen size in both real and screenshot coordinate spaces, scale, and pointer position — so the agent knows this is a read-only environment-info query. It is clear but does not distinguish itself from the sibling cursor_position, which overlaps with the 'pointer position' element.

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?

There is no when-to-use guidance and no mention of the cursor_position sibling, which appears to expose overlapping information. The agent must infer that this is the tool to call before converting between screenshot and real coordinates.

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