add_weigh_in

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states the mutation intent ('Add') and explains arguments, but says nothing about what timestamp is assigned, whether an existing weigh-in for the same date is overwritten or duplicated, whether a valid weight range applies, or what happens on success. This is a thin behavioral profile for a write operation.

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 short and front-loaded with the core action in the first sentence. The Args block is cleanly structured and every line earns its place. It is efficient without 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?

For a simple flat 2-parameter tool with an output schema, the description covers the basics. The main completeness gap is the ambiguity relative to add_weigh_in_with_timestamps — an agent cannot determine which sibling fits its goal. Also missing is any note on timestamp/duplicate semantics, which matters for a health-data write.

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 must compensate, and it partially does: unit_key is usefully explained as 'kg' or 'lb', which the bare schema (no enum) does not provide. However, 'weight: Weight value' is nearly tautological and adds little beyond the property name and type. The description is adequate but not a strong compensation for the missing schema descriptions.

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 states a specific verb and resource: 'Add a new weight measurement.' This is clear and unambiguous. However, it does not differentiate itself from the closely related sibling add_weigh_in_with_timestamps, which presumably does the same thing plus timestamp handling, so an agent cannot tell them apart from this text alone.

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 guidance on when to use this tool versus alternatives. With add_weigh_in_with_timestamps, delete_weigh_ins, get_weigh_ins, and get_daily_weigh_ins in the sibling list, the description gives no hint about the distinguishing condition (e.g., when to add with a default/current timestamp vs. specifying timestamps).

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