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

Annotations include readOnlyHint=true, and the description adds context: it's FREE, returns Aseprite JSON with specific fields, and is for sheets you own. This complements the read-only nature without contradiction, but doesn't detail any potential limitations or side effects (which are minimal for a getter).

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?

Two sentences with no redundant words. The purpose is front-loaded ('FREE' and the data returned), and the 'instead of' clause adds value without bloat.

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?

With no output schema, the description adequately covers the return format (Aseprite JSON) and its contents. It doesn't mention error scenarios or pagination, but for a single-parameter getter this is 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?

Schema description coverage is 0%, so the description's clarification that generation_id is 'for a sheet you own' is essential. It gives meaning to the only parameter, though it doesn't elaborate on format or validation rules.

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 the tool returns specific data (frame rects, registration, fps, pivot, animation tag) in a specific format (Aseprite JSON) for a sheet the user owns. It distinguishes itself from sibling tools like plan_sheet or get_asset by its specialized purpose.

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 a clear condition ('For a sheet you own (its generation id)') and a hint to use it instead of measuring gutters. However, it doesn't explicitly name alternative tools or state when not to use it, leaving some inference to the agent.

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