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

Annotations already mark readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds that it returns seasonalCalendar and regions, which is useful context beyond the annotations, but doesn't detail any other behavioral quirks (e.g., whether it returns null if the slug is unknown). No contradiction 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?

The description is short and front-loaded: it opens with an explicit noun-phrase definition of what the tool returns, then lists the content categories, then gives precise usage guidance. Every sentence earns its place and there is no repetition of schema details.

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 no output schema, the description covers what the tool does, when to use it, and what data it returns (habitat, diet, techniques, baits, seasonal calendar, regions). It's slightly lacking an explicit statement of what happens if the slug doesn't match, but that's minor; the tool is otherwise fully usable from the description alone.

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 coverage is 100%, so the parameter 'slug' is already fully documented in the schema. The description reinforces that the slug comes from search_species and gives an example ('tucunare'), which adds a small practical hint beyond the schema, but the schema covers the essential meaning. Baseline 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?

The description clearly states a specific verb ('Detalhes de uma espécie') and enumerates the exact content covered: habitat, dieta, técnicas, iscas, seasonalCalendar, and fishing regions. It distinguishes itself from sibling tools by focusing on species-level biological/fishing context rather than equipment, locations, or techniques.

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 states when to use: before recommending equipment or location for a specific fish, and for questions about best season / when to fish X. This gives an agent clear routing criteria and implies when not to use it, since equipment/location-specific tools exist as siblings.

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