update-body-measurement

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

No annotations are provided, so the description carries the full burden. It discloses critical behavioral traits: all fields are overwritten, omitted fields are set to null, and returns 404 for missing dates. This goes beyond simple 'update' semantics and helps the agent understand the destructive nature of omitting parameters. However, it does not mention permissions, rate limits, or the success response shape, so slightly less than perfect.

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?

The description is two concise sentences that front-load the purpose ('Update an existing body measurement entry for a given date') followed by the two essential behavioral caveats. Every word earns its place, with no redundancy or fluff.

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 tool with 18 parameters, no annotations, and no output schema, the description covers the most critical operational details: overwrite semantics, null-filling, and 404 behavior. It does not describe the success return value or any prerequisites, but the schema handles parameter meanings and the description clarifies the update semantics, making it largely complete.

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 provides full coverage with descriptions for all 18 parameters (units in cm, kg, etc.), so the baseline is 3. The description adds important parameter behavior: omitted fields are set to null, which is not visible in the schema. This clarifies that updating with a subset of fields will erase unmentioned ones, adding value beyond the schema.

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 clearly states 'Update an existing body measurement entry for a given date', specifying the action (update), the resource (body measurement entry), and the key parameter (date). It also distinguishes itself from sibling tools like create-body-measurement and get-body-measurement by emphasizing 'existing' and the 404 behavior for missing entries.

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: this tool updates an existing entry, and if no entry exists for the date, it returns 404. This implies it is not for creating new entries, but it does not explicitly name alternatives like creating a new measurement. The conditionality is clear enough for an agent to decide when to use it.

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