add_biometric

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

Annotations already cover readOnly, destructive, and idempotent hints. The description adds useful context beyond those: date defaults to today, unit_id must come from that metric's valid units, and the tool is for recording new readings rather than editing or removing. This enriches the annotation profile without contradicting it.

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 compact, well-structured, and front-loaded. The purpose appears in the first sentence, usage guidance follows immediately, and each parameter gets a single clear line. No filler or redundant schema repetition.

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?

With an output schema present and four parameters, the description covers everything needed to invoke the tool correctly: purpose, ID discovery, alternative actions, parameter sources, and date formatting. There are no significant gaps in context.

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 carries the full burden for parameter meaning. It compensates completely: metric_id is sourced from list_biometrics, unit_id is scoped to that metric's units, amount is the measured value, and date includes format plus default behavior. This is exactly what an agent needs.

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 opens with a specific verb and resource: 'Record a biometric measurement, such as weight or body fat.' It clearly distinguishes this creation action from the related siblings by explicitly naming list_biometrics, edit_biometric, and remove_biometric for their respective roles.

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 explicitly tells the agent when to use list_biometrics to find IDs, edit_biometric to correct a wrong value, and remove_biometric when a measurement never happened. This gives direct routing guidance and prevents misuse of add_biometric for corrections or deletions.

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