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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld=false), but the description adds real value beyond them: no upstream dependency, safe to call once per conversation, a public endpoint, and that output is English natural-language text that preserves sources, conditions and pagination. Return-format disclosure is genuinely useful given there is no output 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?

Purpose is front-loaded in the opening clause and the remaining sentences cover usage and output without repetition. It is somewhat list-dense in the first sentence, but every item (category names, call cadence, output nature) earns its place.

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 parameters and no output schema, the description carries the return-value burden and does so reasonably, sketching the output as natural-language English text with preserved sources/conditions/pagination. The exact shape of the returned vocabulary is only loosely described, but for a static reference tool this is nearly complete.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline for a 0-param tool is 4. The description correctly adds no parameter detail, which is appropriate here.

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 role: a vocabulary/lookup that supplies valid filter values for search_courses, then enumerates the exact categories (states, cities, qualification groups, AQF level names, FOE codes, provider/education types, sort values, studentLocation). An agent can immediately tell this is a reference tool rather than a search tool, and it names the sibling it feeds.

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?

"No upstream call; safe to call once per conversation" gives clear usage cadence and dependency guidance, and the phrase "Vocabulary for search_courses" implies calling it before search_courses. It stops short of an explicit when-to-use/when-not statement or naming an alternative, so it does not reach 5.

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