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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description's job is to add context beyond that. It adds licensing info ('CC BY 4.0, no auth required'), source attribution, and describes the response as a ranked list with counts and flags. It does not contradict annotations and provides useful behavioral details beyond the safety profile.

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 well-structured, front-loading the core purpose, then listing output fields, filters, use cases, and source. Each sentence adds value, and it is appropriately sized for a complex tool with five parameters. Slightly longer than minimal but justified by the need to explain the aggregation behavior.

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?

Given the tool has an output schema (not shown) and 100% parameter coverage, the description covers the essential operational aspects: what it generates, what filters exist, who it's for, and licensing. It mentions the return is 'ranked' and includes habitat flags, which clarifies behavior. No critical gaps noted for an agent to correctly invoke it.

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 each parameter already has a clear description. The tool description repeats some filter options (parent taxon, AphiaID, area ID, marine_only) but does not add new semantic meaning beyond what the schema provides. It gives a couple of examples (e.g., 'Mollusca') but the schema itself already includes that example. Baseline 3 is appropriate when the schema carries the explanatory weight.

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 clearly states the tool's purpose: generate a species checklist from OBIS occurrence data, with specific output details (ranked list, counts, taxonomy, AphiaID, habitat flags). It uses a specific verb ('generate') and resource ('checklist'), and distinguishes itself from sibling tools like occurrence_search and taxon_search by emphasizing its checklist aggregation role.

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 mentions use cases ('biodiversity assessments, EIA surveys, species inventories') and explains filtering options, but does not explicitly contrast with sibling tools (e.g., when to use this over obis.marine.occurrence_search). It provides context on applicability but lacks explicit exclusions or alternative tool references.

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