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

Annotations already cover the safety profile (readOnlyHint=true), so the bar is lower. The description still adds real behavioral context: newest-first ordering, 20-per-page pagination, and the mandatory-filter constraint, none of which appear in the schema.

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?

One sentence carries purpose, ordering, page size, and the required-filter rule, followed by the endpoint. The most decision-relevant constraint is placed before the API reference; nothing is padding.

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 correctly covers the essentials of the return set (certificates, newest first, paginated at 20). It leaves the exact certificate fields and pagination-termination behavior unspecified, but the tool is simple enough that this is a minor gap.

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 100%, so the baseline is 3. The description earns above that by supplying a cross-parameter rule the schema cannot express — that course_id and user_id are individually optional but at least one must be supplied.

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?

States a specific verb+resource ('Certificates awarded') with scope ('for a course and/or a user') and ordering ('newest first'). The resource is clearly distinct from sibling list tools (courses, users, payments, event logs), so an agent can route to it without opening the schema.

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?

Gives a concrete usage prerequisite: 'at least one of course_id or user_id is required,' which is exactly the filtering condition an agent needs. It does not name an alternative sibling for related data (e.g., progress or grades), so it stops short of full when/when-not guidance.

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