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

Annotations confirm it is read-only and non-destructive. The description builds on this by detailing the specific operational logic of derived formats ('marked derived:true without persisting it'), adding behavior beyond the simple safety hints provided in the annotations.

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 definition is concise and effectively front-loads the primary function into the first sentence. It is appropriately detailed without being verbose.

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 richness of the input schema and the existence of an output schema, the description fully answers the agent's need to know what data to expect and how the tool behaves with derived assets.

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 60% schema coverage, the description provides necessary semantic context by detailing exactly what is returned (layout, dimensions, read receipt) and listing specialized formats like 'App Store headers/search creatives,' linking the purpose back to specific input types.

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 explicitly states its function: 'Returns one social or store-creative format layout, canvas dimensions and a same-target editing read receipt.' It clearly identifies the resources (layout, dimensions) and scope (social/store-creative formats).

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?

While it doesn't explicitly state 'when' to use it over siblings, it provides important functional guidance by explaining how it handles 'unsaved formats,' marking them as derived without persisting them, which is vital for agents distinguishing its behavior from saving/creation tools.

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