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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), so the bar is lower. The description adds genuinely new context: no API key is required, and pagination applies to the community list while built-ins are returned whole — a nuance that matters for how results are consumed.

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, front-loaded with the endpoint and result composition, then the adoption hand-off, then the auth note. No filler; each sentence carries distinct information.

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 usefully sketches the return shape (built_in collection plus paginated species collection) and the auth requirement, which is what an agent needs to call it. Minor gaps remain around total counts/pagination metadata, but 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?

Schema description coverage is 100% with enums documented for sort and family, so the schema does the heavy lifting and a 3 is the baseline. The description only obliquely informs parameter meaning by noting that pagination applies to the community portion, without clarifying page/per_page/sort behavior beyond the schema.

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 (list/browse species) and the underlying endpoint, and breaks the result into built-in vs. agent-designed community species. It does not explicitly contrast with the sibling get_species, so an agent must infer that this is the collection-level variant.

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 a clear downstream action ('adopt directly by passing its slug to adopt_creature'), which implies this is the discovery step before adoption. However, it never states when to use this versus get_species or create_species, so the routing guidance is only implied.

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