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 meaningful behavior: borderless-frame renders the screenshot without a phone frame, MacBooks are HyperRealistic-3D-only and fill the display (16:10 loses a sliver), and the lid responds to foldAmount. It omits error/failure behavior and permission requirements, but the visual-consequence disclosure is genuinely useful.

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 purpose is front-loaded, but the body is a dense run-on that re-lists every enum value already present in the schema. The grouping-by-platform adds value, yet the flat single-paragraph enumeration of ~21 IDs is verbose where structure or reliance on the schema enum would be tighter.

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 two-param setter with no annotations and no output schema, the description covers the consequential choice (deviceId) and its visual/platform constraints well. The unexplained platformSetId and absence of any error or return behavior keep it from fully 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?

Schema coverage is 0%, so the description must compensate—and it does for deviceId by grouping valid values per platform type and explaining the visual effect of borderless-frame and MacBook devices. platformSetId is never explained, leaving that half of the parameters undocumented in both schema and 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?

States a specific verb and resource: 'Set the device of a platform set.' An agent can tell this apart from sibling setters like set_realistic_frame or set_squircle_frame, though the description never names those alternatives explicitly to sharpen the boundary.

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?

It provides conditional rules about which deviceIds a given platform set accepts (iOS/Android/Social), which implicitly guides correct use, but it never states when to call this tool versus a sibling like set_realistic_frame, nor any prerequisite that the platform set must already exist.

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