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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety and idempotency profile is well-covered. The description adds no extra behavioral context, such as not-found behavior, response format, or rate limits, but with such strong annotations, the description need not repeat them; it simply lacks additional transparency beyond what annotations provide.

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?

The description is a single four-word sentence with no fluff, making it very concise and easy to parse. It is arguably under-specified for a complete tool description, but for such a simple tool with strong annotations and an output schema, this brevity is acceptable and no words are wasted.

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?

The tool is very simple with one parameter and an output schema, so the description need not explain return values. However, it lacks any usage guidance or behavioral nuances, and given the low schema coverage, the overall description is minimally adequate but not thorough for an agent that has no other context.

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 schema has 0% description coverage, and the only param 'id' is a bare string with an example UUID. The description 'by id' merely restates the parameter name and does not explain the expected format, whether it is a UUID, or any constraints. Since schema coverage is low, the description should compensate but does not.

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?

The description 'Single species by id.' clearly identifies the resource and retrieval scope, distinguishing it from the plural sibling tool 'species' for listing all species. While it lacks an explicit verb like 'retrieve' or 'get', the phrase 'by id' strongly implies a fetch operation for a single entity, making the purpose clear enough.

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?

The description provides no guidance on when to use this tool versus alternatives such as the sibling 'species' tool for listing. There is no mention of prerequisites, exclusions, or scenarios where this tool is preferred, leaving the agent to infer usage solely from the name and context.

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