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

Annotations already declare readOnly, idempotent, and closed-world, so the safety profile is covered. The description adds genuinely non-obvious behavior: the result set is limited to one certification, defaults to the learner's latest when the account is linked, and never surfaces exam questions or answer keys.

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?

Four short sentences with zero filler; the trigger condition leads, followed by return shape, then the negative boundaries. Nothing repeats the title or the annotations.

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 carries the burden of describing return values and does so ('published guide titles and links'). Combined with the scope and exclusion rules, an agent has everything needed to call it correctly.

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 coverage is 100%, so baseline is 3, but the description adds real meaning by explaining that only one certification's guides are returned and that the learner's latest program is used when the account is linked — context the enum alone does not convey. It does not describe the query matching semantics, which the schema already covers.

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 and resource ('search... study guides', 'returns published guide titles and links') plus the scope: one certification, defaulting to the learner's latest. This clearly separates it from practice_question and get_result_review siblings that deal with questions/results.

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?

'Use this when someone asks for CertArc study guides on a topic' gives a clear trigger, and 'Not a general web search' plus 'Never returns exam questions or answer keys' carve out the when-not case. It stops short of naming the specific sibling tool an agent should use instead for exam questions, so the routing is implied rather than explicit.

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