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

With no annotations, the description carries the full behavioral burden. It usefully discloses fallback behavior when the store does not provide the requested guide, but it does not state that the operation is read-only, whether it has side effects, or any permission requirements.

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 three sentences, front-loaded with the core action and followed by usage triggers and fallback behavior. Every sentence adds useful information without redundancy.

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 simple render tool with an output schema, the description covers purpose, usage triggers, and the no-guide fallback. The main gap is the undocumented query parameter, but otherwise it is complete enough for an agent to select and invoke the tool.

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?

There is one optional query parameter with 0% schema description coverage, so the description should compensate. It never explains what the query should contain, its format, or how the default "size guide" is used, leaving parameter meaning largely undocumented.

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 uses a specific verb, "Render," and a specific resource, "size guide or size chart," making the tool's purpose immediately clear. It distinguishes the tool from cart and product siblings through the sizing domain, though it does not explicitly name an alternative sibling.

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 explicitly lists when to use the tool: requests about sizing, measurements, clothing sizes, children's sizes, or footwear sizing. It does not provide when-not-to-use guidance or name alternative tools, but the usage context is clear.

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