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

Annotations already declare readOnlyHint and idempotentHint, covering safety. The description adds valuable non-obvious behavior: the synonym/acceptedKey field relationship and the extinct field's absence semantics. These details are not derivable from schema or annotations and help an agent interpret results correctly. No contradictions.

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?

Two sentences, no extraneous fluff. The core action and return value are front-loaded, followed by usage context and edge-case clarifications. Every sentence earns its place; nothing repetitive or vague.

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 has a rich output schema, so the description need not explain return values. It covers purpose, usage trigger, and unusual field behavior. For a single-parameter read-only tool with this much context, nothing critical 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% — the only parameter (taxonKey) has a descriptive schema. The description does not add extra parameter-level meaning, but given the schema already documents the parameter clearly, the baseline of 3 is appropriate.

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?

Description states a specific verb ('Fetch'), resource ('single backbone taxon'), and the key identifier ('by its GBIF taxon key'). It also enumerates the returned content (classification, authorship, status, vernacular name, descendant count, publication reference), which distinguishes it clearly from sibling tools like gbif_match_species (which returns a match summary) and gbif_get_species_children (which returns children). No ambiguity.

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?

Explicitly says 'Use after gbif_match_species when you need the complete record rather than the match summary,' providing a clear trigger and pointing to the relevant sibling. It does not state when NOT to use it (e.g., 'do not use for bulk matching'), but the positive guidance is sufficient for typical agent routing.

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