pack_weight_sum

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

With no annotations, the description must disclose behavior itself. It states the input format and that it returns total grams and pounds, which is useful. However, it omits details like how qty is handled (multiplied?), defaults, or empty-array behavior, leaving some behavioral ambiguity.

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 one focused sentence followed by a compact format spec and return statement. Every word contributes value; there is no redundancy or irrelevant content.

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 tool, the description covers key aspects: input structure and output units. It lacks a detailed return format (e.g., object keys) but given the simplicity and no output schema, it is adequately complete for an agent to use.

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 0%, but the description provides structure: 'items: [{name, grams, qty?}]', clarifying that items is an array of objects with those fields. It does not elaborate on the meaning of qty beyond optionality, so it only partially compensates for the schema's lack of 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 starts with a clear verb 'Sum' and specifies the resource 'gear pack items' and unit 'grams'. It accurately distinguishes this tool from siblings like unit_convert, as it sums weights rather than merely converting units.

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 implies when to use the tool (summing gear pack items in grams) but does not explicitly mention alternatives or exclusion cases. It provides a direct, straightforward use case without deeper guidance about when to choose this over other tools.

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