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

Annotations already declare readOnly, idempotent, and closed-world, so the safety profile is covered. The description earns credit by disclosing the return shape (studies as short cards, pathway relations as one-line claims) and the truncation behavior tied to studies_limit, which no annotation or schema conveys. It does not say what happens when the entity is not found.

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?

A single dense sentence that front-loads the payload (entity plus studies plus pathway relations) before the input note. Nothing is wasted, though the parenthetical type list makes it slightly packed.

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?

With no output schema, the description carries the return-value burden and does so adequately, and annotations handle the safety profile. Remaining gaps (not-found behavior, whether pathway relations carry direction) are minor for a single-record lookup tool.

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?

At 50% schema coverage, the description compensates: it explains that the entity argument accepts an id, a name, or a synonym (beyond the schema's bare examples), and that studies_limit caps the number of study cards returned as 'first studies_limit'. The schema's default/min/max for studies_limit are not restated, but the semantic intent is clear.

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?

States a concrete resource (one entity) and enumerates exactly what comes back: linked studies as short cards and every pathway relation as a one-line claim. The singular framing implicitly contrasts with the search_entities sibling, but no sibling is named, so differentiation is left to inference.

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?

Usage is only implied by the singular/plural contrast with search_entities; there is no explicit statement of when to pick this over search_entities, find_relations, or evidence_between. The closing sentence about accepted identifier forms is input guidance, not usage guidance.

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