Get facet taxonomy

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description focuses on semantics. It adds a genuinely useful caveat that these are allowed label constants rather than counts of labels present in the library, which prevents a common misinterpretation; it does not describe the response envelope, but nothing here is destructive or costly.

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 tight sentences: what it returns is front-loaded, then usage routing, then the semantic caveat. No filler and no repetition of the title or 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?

For a zero-parameter, annotation-covered, no-output-schema tool, the description names the four label lists it returns and clarifies they are server constants. Only minor gap is that the exact response shape (e.g., key names / structure of each list) is left implicit.

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 no parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description correctly spends its space on return-contents semantics instead of inventing parameter guidance.

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 ('Return') plus the exact contents: format, performance-tier, length-bucket and hook label lists. It also explicitly distinguishes itself from get_taxonomy, so an agent can separate the two without opening either 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 precondition ('Use before classify_facets or query_by_facets') and names the alternative for a different need ('use get_taxonomy for saved per-item hook-classification rows'). When-to-use, when-to-use-something-else, and the discriminator are all present.

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