Save Fitatu Body Measurement

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

The description adds meaningful PATCH semantics not present in the annotations: omitted values stay unchanged and existing values cannot be cleared. It also notes the authenticated-user requirement. The destructiveHint=true annotation is not contradicted because overwriting an existing measurement is still a mutation, even though values cannot be nulled.

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 dense sentences with no filler. The primary verb and scope are front-loaded, and the key exception ('cannot be cleared') is placed at the end without unnecessary detail.

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?

The description, full schema, and output schema together cover most of what an agent needs to call this correctly. The only notable gap is whether a measurement record must already exist for the date or whether the call can create one, since 'save' and 'partially updates' leave this slightly ambiguous.

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?

The schema already documents every parameter with 100% coverage, but the description adds global parameter behavior: omitted optional values remain unchanged and clearing is impossible. This is important semantic information that cannot be inferred from the schema alone.

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 uses a specific verb and resource: 'Partially updates the authenticated Fitatu user's body measurement for an explicit date.' This clearly distinguishes it from the sibling get_body_measurement and other update tools. It is not a tautology of the name or title.

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?

The description gives clear context for use: it is for partial updates to a body measurement on a specific date, and omitted values remain unchanged. It also implies a when-not case by stating existing values cannot be cleared, though it does not explicitly name alternatives like get_body_measurement for reading.

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