motion_measure

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds that it returns computed metrics (path length and max sample-to-sample distance), which is useful since no output schema exists, but it does not say whether values come from evaluated or baked/native curves, what units are used, or whether anything is cached or mutated.

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 front-loaded sentence with no filler or redundancy. Brevity is the right instinct here, though the sentence is terse to the point of being cryptic.

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?

Four parameters at 0% schema coverage, three of them required, plus no output schema, demand more than one sentence. The description never covers the required frame range, the object identifier format, the step default, or the shape of the returned measurements — an agent cannot call this correctly without guessing.

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% for four parameters, so the description carries the full burden and largely fails: it never explains that 'objects' is a list of object identifiers, that 'first'/'last' bound the frame range, or that 'step' controls the sampling interval (only obliquely implied by 'sample-to-sample'). Almost no meaning is added beyond the bare schema types.

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 verb 'Sample' plus the metrics named ('path length', 'largest sample-to-sample distance') indicate a motion-measurement tool, but the phrase 'actual native trajectories' is vague and the description never distinguishes it from the sibling 'motion_sample' or 'character_motion_inspect'. An agent knows roughly what it computes but not exactly what it measures over.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives such as motion_sample or character_motion_inspect. The agent must infer from the name alone that this is the diagnostic/measurement path rather than the sampling path.

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