previewapk_screenshot

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

With no annotations, the description carries the full burden and does disclose non-obvious behavior: the download auto-resumes on a cut connection, and scale trades fidelity for transfer size. It still omits the return medium, whether the device parameter is required, and any latency/rate characteristics.

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?

Three sentences, front-loaded with the core purpose, and every sentence carries information. A minor redundancy exists in restating the scale tradeoff that the schema already implies.

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 2-parameter tool with no output schema, the description covers purpose, usage, and transfer behavior, and gestures at the return value ('an image you can see'). The unexplained 'device' parameter is the remaining gap.

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 coverage is 50%: 'scale' is defined in the schema, and the description adds a weak-network scenario ('pass scale=0.5 ... for a quarter-size transfer'), which is marginal new meaning. The 'device' parameter is undocumented in both the schema and the description, leaving the coverage gap uncompensated.

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+resource ('Capture the device's current screen as an image') and signals its relationship to the sibling previewapk_hierarchy ('the real screen — it agrees with the hierarchy'). The differentiation is present, though it stops short of explicit 'use X instead of Y' routing.

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?

'Use it to verify your changes look right' gives a clear use context matching the 4-level rubric. There is no guidance about when NOT to use it or which sibling to prefer when the agent just needs the textual tree (previewapk_hierarchy).

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