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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds the useful behavioral fact that unspecified measurements may be omitted rather than defaulted, but says nothing about what happens on duplicate dates, whether this appends to an existing assessment, or what the response contains.

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 compact sentence plus a short imperative, with the resource and field list front-loaded and no filler. The efficiency is good, but the skinfold reference points at fields that don't exist in the schema, which slightly undermines the density.

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 20-parameter mutation tool with no output schema, the description covers only a subset of the accepted fields and never states what happens on success or failure. Combined with thin annotations, an agent still lacks enough information to call this confidently across all parameters.

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 only 10%, so the description must compensate and it partially does: it supplies units (cm for circumferences, mm for skinfolds) that the schema lacks entirely. But it omits half the parameters (height_cm, muscle_mass_kg, resting_heart_rate, notes, systolic/diastolic pairing) and even references skinfolds that have no corresponding schema property, leaving many fields undocumented anywhere.

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 and resource ('Saves a new physical assessment for a student') and enumerates the measurement categories it accepts, so the agent knows exactly what this creates. It does not explicitly contrast with update_assessment or attach_assessment_to_student, though the create/update distinction is inferable from the name.

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?

'Send only what was measured' gives real guidance on partial payloads, which is the main usage ambiguity for a 20-parameter tool with 2 required fields. However, there is no guidance on when to use this versus update_assessment for an existing record, nor on prerequisites such as the student already existing.

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