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

Annotations already declare the operation read-only and idempotent, and the description adds beyond that by disclosing an access requirement ('Requires the Scale plan or higher') and clarifying the scope of returned data. This satisfies the bar of adding behavioral/operational context beyond the structured 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?

Three short sentences each earn their place: the first defines the resource, the second eliminates the most likely confusion with a sibling tool, and the third states a binding prerequisite. It is front-loaded and free of filler.

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 no-parameter, read-only, idempotent list tool with an output schema available, the description covers everything an agent needs: what is returned, how it differs from the closest sibling, and the required plan level. Nothing essential is missing.

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 are zero parameters, so the description has no parameter semantics to add. The schema coverage is 100% because the schema is empty, meaning there is nothing undocumented. The baseline of 4 for a zero-parameter tool applies; the description correctly focuses on the meaning of the returned resource instead.

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 states a specific verb and resource: 'Lists certificate templates' and immediately clarifies what a certificate template is (the design of the PDF a learner gets on passing). It explicitly distinguishes this from issued certificates and names the sibling tool list_issued_certificates, so an agent can reliably select the correct tool.

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 gives explicit when-to-use guidance: use this tool to list templates, not learner-issued certificates, pointing directly to list_issued_certificates as the alternative. It also provides a prerequisite: 'Requires the Scale plan or higher,' which is necessary context for selecting or attempting the call.

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