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 profile is known. The description adds valuable context beyond annotations by stating the source (OBIS + WoRMS), licensing (CC BY 4.0), that no authentication is required, and enumerating the fields returned (taxonomic hierarchy, AphiaID, status, accepted name, habitat flags, vernacular names). No contradictions with annotations.

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 sentences with zero waste: purpose, search semantics, return fields, and source/license/auth are all covered compactly. The core purpose is front-loaded, and every clause 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?

For a single-parameter read-only lookup with an output schema, the description is complete. It covers the input type, expected output fields, data source, licensing, and authentication requirements. The output schema handles return structure, and annotations handle safety. No meaningful gaps remain.

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%, so baseline is 3. The description adds meaning by explicitly stating the acceptable taxonomic ranks (genus, species, or higher taxon), complementing the schema's examples (Tursiops truncatus, Gadus, Cetacea). This clarifies the parameter scope beyond the schema alone.

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 opens with a specific verb and resource: 'Look up marine species taxonomy in the World Register of Marine Species (WoRMS) via OBIS.' It clearly differentiates this from sibling OBIS tools (occurrence_search, checklist, dataset_search) and other taxonomy tools by specifying the WoRMS-backed taxonomic lookup scope. The title 'Marine Taxon Lookup' reinforces the purpose.

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 gives clear context for when to use this tool: 'Search by scientific name (genus, species, or higher taxon)' and describes the expected output. However, it does not explicitly name alternative tools or state when not to use them, despite several closely related sibling tools (worms.species.search, science.itistaxonomy.search_scientific, gbif.biodiversity.species_search). This is a clear-context-but-no-exclusions case.

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