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

Annotations already declare read-only, idempotent, closed-world and non-destructive, so safety is covered. The description adds genuinely non-obvious behavior: missing specs appear as null rather than being omitted, each model carries an assessment, and mismatched types produce a refusal with an explanation instead of an error or partial result.

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?

Two tight sentences plus one example; the output shape, the null convention and the refusal rule are all front-loaded with no filler. Nothing repeats the annotations verbatim.

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 tool with an output schema and full annotation coverage, the description supplies everything left uncovered: null semantics, same-type constraint, refusal behavior, and a usage example. An agent could call this correctly without opening anything else.

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 0%, so the description has to carry the semantics and it largely does: it explains that ids identify models of the same type, that 2-4 are required, and gives a concrete example payload. It does not specify accepted id format (slug vs numeric) beyond the example.

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 specific verb+resource (side-by-side spec comparison) and pins the scope: 2-4 models of the same robot type. The row-per-spec / value-per-model output shape and the concrete example make it immediately distinguishable from single-entity siblings like get_robot_model or get_stat.

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?

Gives clear usage boundaries: 2-4 models, must be the same robot type, mixed types are refused with an explanation. It does not explicitly route the agent to a sibling (e.g. get_robot_model for a single model), so it falls short of an explicit alternatives statement.

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