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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is fully covered without the description. The description earns credit beyond that by disclosing the shape of the returned record — roles and birth/death years for people, kind and scored film for music — which matters because there is no output schema. The word "compact" also usefully signals an abbreviated view rather than a full record.

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?

One tight sentence with the core action front-loaded and the entity enumeration folded into the same clause. Nothing is redundant and nothing could be cut without losing the return-shape information.

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 one-parameter read tool with full annotation coverage, the description supplies the piece annotations cannot: what the returned record contains for each entity kind. It is nearly complete, though it omits the not-found behavior an agent would want before relying on the result.

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?

There is a single parameter with 100% schema description coverage, including a pattern and concrete examples ("person-tarkovsky", "film-stalker"), so the schema carries the semantics. The description only restates "by id" and adds the categories of id without extra format rules or edge-case behavior, which is the baseline for a fully documented parameter.

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 gives a specific verb and resource ("compact record of any entity by id") and enumerates the entity kinds it covers — film, person, music work — so an agent knows exactly what lookup this performs. It stops short of naming a sibling like renoir_get_film to explain why it would choose this general lookup over the film-specific one, so differentiation is implicit rather than explicit.

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: the phrase "by id" signals this is a direct key lookup, which suggests renoir_search is the path when you only have a name. There is no explicit statement of when to prefer renoir_get_film or renoir_get_connections, and no note about what happens when the id is unknown.

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