screenshot

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 only states the action and format, but omits key behaviors: whether the simulator must be booted, what state is captured, where the file is saved when outputPath is not set (auto-generated path location is not explained), and whether there are any side effects. This is insufficient for the agent to predict tool behavior.

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 of 9 words, which is very concise. It efficiently states the main action. However, while concise, it sacrifices valuable context that could be added without becoming verbose. A score of 4 reflects good conciseness with room to include brief but important behavioral notes.

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 the tool's simplicity (2 params, no output schema), the description is still incomplete. It lacks necessary context such as simulator state requirements, where the output file is stored when not specified, and whether the tool is destructive or read-only. The presence of siblings like 'screen_record', 'simulator_shutdown', etc., makes it unclear when this tool is the right choice. The description does not provide a complete picture for tool selection and invocation.

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% (both 'deviceId' and 'outputPath' have descriptions in the schema). The tool description adds no additional information about the parameters beyond what the schema already provides. Per guidelines, baseline 3 is appropriate when schema does the heavy lifting, and there is no extra value from the description.

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 'Capture a screenshot from a simulator as PNG' uses a specific verb ('capture') and clearly identifies the resource ('screenshot from a simulator') and output format ('as PNG'). This distinguishes it from siblings like 'screen_record' (video) and other simulator actions, making the purpose immediately clear.

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 provides no guidance on when to use this tool versus alternatives, particularly 'screen_record' or other capture-related tools. There is no mention of prerequisites (e.g., simulator must be booted) or conditions that would make this tool preferable. The agent is left to infer usage context from the name alone.

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