screenshot_app

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

There are no annotations, so the description carries the full burden. It discloses valuable behavioral traits: partial and case-insensitive title matching, capturing only the target window, PNG output, and not stealing focus or disrupting the desktop. It does not mention behavior when no window matches or how the PNG is delivered (file path vs. inline image), which is a minor gap.

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 compact, front-loaded with the core purpose, and organized with an Args section. Every sentence adds value, including the case-insensitive matching detail and the concrete example. There is no wasted or redundant content.

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?

For a single-parameter, low-complexity tool, the description covers the purpose, parameter semantics, and a useful prerequisite. Without an output schema, it stops just short of specifying the exact return format or where the PNG is written, and it does not cover error behavior. Still, an agent can invoke the tool correctly based on this description alone.

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 only defines window_title as a type string with no description, so the description fully compensates. It explains that the title can be full or partial, is matched case-insensitively, and provides a concrete example. This gives an agent everything needed to populate the parameter correctly.

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 a specific action and resource: taking a screenshot of a running application window by matching its title. It adds useful detail about capturing only that window as PNG, but it does not explicitly differentiate this from sibling screenshot tools like adb_screenshot or sim_screenshot. The purpose is clear, but sibling differentiation is only implicit.

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 includes an explicit usage hint: use list_app_windows first to find the exact window title. This gives clear context for an important prerequisitecars. Missing are explicit exclusions such as 'for device screenshots use adb_screenshot' or 'for simulator screenshots use sim_screenshot', so the guidance is good but not fully exhaustive.

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