Take a screenshot of the simulator

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

No annotations are present, so the description carries the disclosure burden. It clearly states capture behavior, PNG output, saved file path, pixel dimensions, and logical dimensions/scale. It does not mention failure behavior when no simulator is booted, but overall it is transparent about what the tool does and returns.

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?

Two sentences with no filler: the first gives the action and output format, the second enumerates the returned data and explains why it is useful. The key information 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?

Given there is no output schema and no annotations, the description does well by enumerating the main return fields and connecting them to tap coordinates. Minor omissions are exact failure behavior and file lifecycle, but for a zero-parameter tool this is still largely complete.

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 has zero parameters, so a baseline of 4 applies. There is nothing additional the description needs to explain for invocation, and invoking without arguments is self-explanatory.

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?

States a specific verb ('Capture') and resource ('booted simulator screen') plus the output format ('as a PNG'). It is clearly distinct from sibling tools like tap, get_accessibility_tree, or list_devices.

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 booted precondition and the coordinate-derivation motivation imply when to call it, but it does not name any alternative or exclusion. It never tells an agent when to prefer get_accessibility_tree or another inspection tool.

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