compose_screenshot

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

No annotations are provided, so the description carries full burden. It discloses the rendering process (auto-uppercasing for language, device frame inclusion, exact store dimensions), but does not clarify side effects, permissions, or output format beyond stating 'output has exact store dimensions.'

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 two sentences long, front-loaded with the main purpose, and every clause adds necessary detail without redundancy. It is optimally concise.

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 8 parameters, full schema coverage, no output schema, and sibling tools, the description provides a solid mental model of the tool's function and output characteristics. Missing are error handling hints or return value details, but for a single-purpose generation tool it is largely sufficient.

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?

With 100% schema description coverage, the baseline is 3. The description adds value by explaining that `verb` and `descriptor` form a headline, that it is auto-uppercased, and that the app screenshot is placed inside a device frame with output dimensions matching the preset. This goes beyond the schema descriptions.

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 that the tool renders a single store-ready marketing screenshot with specific components (brand background, headline, app screenshot inside device frame). It distinguishes itself from siblings like `generate_set` (which likely handles multiple) by specifying 'one' screenshot.

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 does not provide any guidance on when to use this tool versus alternatives like `generate_set` or `create_showcase`. There is no mention of exclusions or context for sibling tools, leaving the agent to infer usage from the purpose alone.

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