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

Annotations already provide readOnlyHint and idempotentHint, but the description adds valuable context: it never raises a protocol error, returns an error object on invalid input with an example, and clarifies that the skill is automatically chosen. This goes beyond the annotations by detailing the error behavior and output format.

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 well-structured: starts with a clear summary, followed by an example, usage guidelines, and error handling. While it is not extremely terse, every sentence adds necessary information. It is front-loaded with the core purpose and example, making it easy to scan.

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 tool's simplicity (one parameter, straightforward output), the description covers all essential aspects: input, output shape, usage context, differentiation from sibling, error handling, and safety guarantees (read-only, idempotent). The presence of an output schema further supports completeness.

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?

The input schema already covers the slug parameter with 100% description coverage, but the description adds a concrete example of typical input and output, explains the error behavior for invalid slugs, and reinforces the source of the slug (list_products). This provides extra semantic value beyond the schema alone.

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 loads a product's free gateway skill with complete instructions, using the verb 'load' and specifying the resource. It distinguishes itself from the sibling 'get_full_skill' by noting that this tool is for the free gateway skill only, while other skills require a paid plan and a skill_name parameter.

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 explicitly says 'Use when the caller wants usable instructions immediately' and contrasts with 'Not for the product's other skills: those are named and need get_full_skill with a skill_name, which requires a paid plan.' It also provides error handling guidance, stating that on invalid input it returns an error object with a fix suggestion and that it's safe to retry.

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